Blood Biology I | Biology | Visionlearning

<!DOCTYPE html> <html lang="en" dir="ltr"> <head>  <meta http-equiv="X-UA-Compatible" content="ie=edge"> <meta charset="utf-8"> <base href="https://www.visionlearning.com"> <title>Blood Biology I | Biology | Visionlearning</title> <link rel="canonical" href="https://www.visionlearning.com/en/library/biology/2/blood-biology-i/242"> <meta name="description" content="Knowledge of blood components brought about a revolution in surgery through safe transfusion. The module traces the development of our understanding of blood over centuries, beginning in 1628 with English physician William Harvey's breakthrough research on circulation. With a focus on early 20th-century experiments by Austrian researcher Karl Landsteiner, the module shows how the identification of clotting factors, blood types, and antigens was critical to medical science. Whole blood, plasma, serum, and different types of blood cells are defined."> <meta name="keywords" content="blood, blood types, Landsteiner, blood plasma, platelet, serum"> <meta name="viewport" content="width=device-width, initial-scale=1.0, shrink-to-fit=no"> <meta name="msvalidate.01" content="D8E20F39AD48052260032E56DE409970"> <script type="application/ld+json"> { "@context": "http://schema.org/", "@type": "Article", "mainEntityOfPage": { "@type": "WebPage", "@id": "https://visionlearning.com/en/library/biology/2/blood-biology-i/242" }, "name": "Blood Biology I", "headline": "Blood Biology I: Components of blood", "author": [ { "@type": "Person", "name": "David Warmflash, MD" } , { "@type": "Person", "name": "Nathan H Lents, Ph.D." }], "datePublished": "2016-09-03 15:22:53", "dateModified": "2017-02-12T08:30:00+05:00", "image": { "@type": "ImageObject", "url": "/img/library/moduleImages/featured_image_242-23061209062353.jpeg", "width": 696, "height": 464 }, "publisher": { "@type": "Organization", "name": "Visionlearning, Inc.", "logo": { "@type": "ImageObject", "url": "http://visionlearning.com/images/logo.png", "width": 278, "height": 60 } }, "description": "Knowledge of blood components brought about a revolution in surgery through safe transfusion. The module traces the development of our understanding of blood over centuries, beginning in 1628 with English physician William Harvey's breakthrough research on circulation. With a focus on early 20th-century experiments by Austrian researcher Karl Landsteiner, the module shows how the identification of clotting factors, blood types, and antigens was critical to medical science. Whole blood, plasma, serum, and different types of blood cells are defined.", "keywords": "blood, blood types, Landsteiner, blood plasma, platelet, serum", "inLanguage": { "@type": "Language", "name": "English", "alternateName": "en" }, "copyrightHolder": { "@type": "Organization", "name": "Visionlearning, Inc." }, "copyrightYear": "2016"} </script> <meta property="og:url" content="https://visionlearning.com/en/library/biology/2/blood-biology-i/242"> <meta property="og:title" content="Blood Biology I | Biology | Visionlearning" /> <meta property="og:type" content="website"> <meta property="og:site_name" content="Visionlearning"> <meta property="og:description" content="Knowledge of blood components brought about a revolution in surgery through safe transfusion. The module traces the development of our understanding of blood over centuries, beginning in 1628 with English physician William Harvey's breakthrough research on circulation. With a focus on early 20th-century experiments by Austrian researcher Karl Landsteiner, the module shows how the identification of clotting factors, blood types, and antigens was critical to medical science. 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href="/en/library/earth-science/6/ocean-currents/282">Ocean Currents</a></li> <li><a href="/en/library/earth-science/6/water-in-the-atmosphere/289">Water in the Atmosphere</a></li> <li><a href="/en/library/earth-science/6/history-of-earths-atmosphere-i/202">History of Earth's Atmosphere I</a></li> <li><a href="/en/library/earth-science/6/history-of-earths-atmosphere-ii/203">History of Earth's Atmosphere II</a></li> <li><a href="/en/library/earth-science/6/earths-atmosphere/107">Earth's Atmosphere</a></li> <li><a href="/en/library/earth-science/6/factors-that-control-earths-temperature/234">Factors that Control Earth's Temperature</a></li> <li><a href="/en/library/earth-science/6/circulation-in-the-atmosphere/255">Circulation in the Atmosphere</a></li> </ul> </div> <button class="accordion__button" id="acc-button-hazards" data-accordion="button" aria-controls="acc-panel-hazards" aria-expanded="false"> <span class="accordion__button__label"> Hazards </span> </button> <div 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aria-controls="acc-panel-environmental-science" aria-expanded="false"> <span class="accordion__button__label"> Environmental Science </span> </button> <div class="accordion__panel" id="acc-panel-environmental-science" data-accordion="panel" aria-labelledby="acc-button-environmental-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-ecology" data-accordion="button" aria-controls="acc-panel-ecology" aria-expanded="false"> <span class="accordion__button__label"> Ecology </span> </button> <div class="accordion__panel" id="acc-panel-ecology" data-accordion="panel" aria-labelledby="acc-button-ecology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/biodiversity-i/276">Biodiversity I</a></li> <li><a href="/en/library/environmental-science/61/biodiversity-ii/281">Biodiversity II</a></li> <li><a href="/en/library/environmental-science/61/ecosystem-services/279">Ecosystem Services</a></li> <li><a href="/en/library/environmental-science/61/population-biology/287">Population Biology</a></li> </ul> </div> <button class="accordion__button" id="acc-button-earth-cycles" data-accordion="button" aria-controls="acc-panel-earth-cycles" aria-expanded="false"> <span class="accordion__button__label"> Earth Cycles </span> </button> <div class="accordion__panel" id="acc-panel-earth-cycles" data-accordion="panel" aria-labelledby="acc-button-earth-cycles" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/the-nitrogen-cycle/98">The Nitrogen Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-carbon-cycle/95">The Carbon Cycle</a></li> <li><a href="/en/library/environmental-science/61/the-phosphorus-cycle/197">The Phosphorus Cycle</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/environmental-science/61/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/environmental-science/61/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-general-science" data-accordion="button" aria-controls="acc-panel-general-science" aria-expanded="false"> <span class="accordion__button__label"> General Science </span> </button> <div class="accordion__panel" id="acc-panel-general-science" data-accordion="panel" aria-labelledby="acc-button-general-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-methods" data-accordion="button" aria-controls="acc-panel-methods" aria-expanded="false"> <span class="accordion__button__label"> Methods </span> </button> <div class="accordion__panel" id="acc-panel-methods" data-accordion="panel" aria-labelledby="acc-button-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-scientific-method/45">The Scientific Method</a></li> </ul> </div> <button class="accordion__button" id="acc-button-measurement" data-accordion="button" aria-controls="acc-panel-measurement" aria-expanded="false"> <span class="accordion__button__label"> Measurement </span> </button> <div class="accordion__panel" id="acc-panel-measurement" data-accordion="panel" aria-labelledby="acc-button-measurement" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/the-metric-system/47">The Metric System</a></li> </ul> </div> <button class="accordion__button" id="acc-button-physical-properties" data-accordion="button" aria-controls="acc-panel-physical-properties" aria-expanded="false"> <span class="accordion__button__label"> Physical Properties </span> </button> <div class="accordion__panel" id="acc-panel-physical-properties" data-accordion="panel" aria-labelledby="acc-button-physical-properties" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/general-science/3/temperature/48">Temperature</a></li> <li><a href="/en/library/general-science/3/density-and-buoyancy/37">Density and Buoyancy</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-math-in-science" data-accordion="button" aria-controls="acc-panel-math-in-science" aria-expanded="false"> <span class="accordion__button__label"> Math in Science </span> </button> <div class="accordion__panel" id="acc-panel-math-in-science" data-accordion="panel" aria-labelledby="acc-button-math-in-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-equations" data-accordion="button" aria-controls="acc-panel-equations" aria-expanded="false"> <span class="accordion__button__label"> Equations </span> </button> <div class="accordion__panel" id="acc-panel-equations" data-accordion="panel" aria-labelledby="acc-button-equations" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/unit-conversion/144">Unit Conversion</a></li> <li><a href="/en/library/math-in-science/62/linear-equations/194">Linear Equations</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-i/206">Exponential Equations I</a></li> <li><a href="/en/library/math-in-science/62/exponential-equations-ii/210">Exponential Equations II</a></li> <li><a href="/en/library/math-in-science/62/scientific-notation/250">Scientific Notation</a></li> <li><a href="/en/library/math-in-science/62/measurement/257">Measurement</a></li> </ul> </div> <button class="accordion__button" id="acc-button-statistics" data-accordion="button" aria-controls="acc-panel-statistics" aria-expanded="false"> <span class="accordion__button__label"> Statistics </span> </button> <div class="accordion__panel" id="acc-panel-statistics" data-accordion="panel" aria-labelledby="acc-button-statistics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/introduction-to-descriptive-statistics/218">Introduction to Descriptive Statistics</a></li> <li><a href="/en/library/math-in-science/62/introduction-to-inferential-statistics/224">Introduction to Inferential Statistics</a></li> <li><a href="/en/library/math-in-science/62/statistical-techniques/239">Statistical Techniques</a></li> </ul> </div> <button class="accordion__button" id="acc-button-trigonometric-functions" data-accordion="button" aria-controls="acc-panel-trigonometric-functions" aria-expanded="false"> <span class="accordion__button__label"> Trigonometric Functions </span> </button> <div class="accordion__panel" id="acc-panel-trigonometric-functions" data-accordion="panel" aria-labelledby="acc-button-trigonometric-functions" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/math-in-science/62/wave-mathematics/131">Wave Mathematics</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-physics" data-accordion="button" aria-controls="acc-panel-physics" aria-expanded="false"> <span class="accordion__button__label"> Physics </span> </button> <div class="accordion__panel" id="acc-panel-physics" data-accordion="panel" aria-labelledby="acc-button-physics" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-light-and-optics" data-accordion="button" aria-controls="acc-panel-light-and-optics" aria-expanded="false"> <span class="accordion__button__label"> Light and Optics </span> </button> <div class="accordion__panel" id="acc-panel-light-and-optics" data-accordion="panel" aria-labelledby="acc-button-light-and-optics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/the-nature-of-light/132">The Nature of Light</a></li> <li><a href="/en/library/physics/24/electromagnetism-and-light/138">Electromagnetism and Light</a></li> </ul> </div> <button class="accordion__button" id="acc-button-mechanics" data-accordion="button" aria-controls="acc-panel-mechanics" aria-expanded="false"> <span class="accordion__button__label"> Mechanics </span> </button> <div class="accordion__panel" id="acc-panel-mechanics" data-accordion="panel" aria-labelledby="acc-button-mechanics" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/physics/24/defining-energy/199">Defining Energy</a></li> <li><a href="/en/library/physics/24/waves-and-wave-motion/102">Waves and Wave Motion</a></li> <li><a href="/en/library/physics/24/gravity/118">Gravity</a></li> <li><a href="/en/library/physics/24/thermodynamics-i/200">Thermodynamics I</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-process-of-science" data-accordion="button" aria-controls="acc-panel-process-of-science" aria-expanded="false"> <span class="accordion__button__label"> Process of Science </span> </button> <div class="accordion__panel" id="acc-panel-process-of-science" data-accordion="panel" aria-labelledby="acc-button-process-of-science" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-introduction" data-accordion="button" aria-controls="acc-panel-introduction" aria-expanded="false"> <span class="accordion__button__label"> Introduction </span> </button> <div class="accordion__panel" id="acc-panel-introduction" data-accordion="panel" aria-labelledby="acc-button-introduction" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-process-of-science/176">The Process of Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-the-culture-of-science" data-accordion="button" aria-controls="acc-panel-the-culture-of-science" aria-expanded="false"> <span class="accordion__button__label"> The Culture of Science </span> </button> <div class="accordion__panel" id="acc-panel-the-culture-of-science" data-accordion="panel" aria-labelledby="acc-button-the-culture-of-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-nature-of-scientific-knowledge/185">The Nature of Scientific Knowledge</a></li> <li><a href="/en/library/process-of-science/49/scientists-and-the-scientific-community/172">Scientists and the Scientific Community</a></li> <li><a href="/en/library/process-of-science/49/scientific-ethics/161">Scientific Ethics</a></li> <li><a href="/en/library/process-of-science/49/scientific-institutions-and-societies/162">Scientific Institutions and Societies</a></li> </ul> </div> <button class="accordion__button" id="acc-button-ideas-in-science" data-accordion="button" aria-controls="acc-panel-ideas-in-science" aria-expanded="false"> <span class="accordion__button__label"> Ideas in Science </span> </button> <div class="accordion__panel" id="acc-panel-ideas-in-science" data-accordion="panel" aria-labelledby="acc-button-ideas-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/theories-hypotheses-and-laws/177">Theories, Hypotheses, and Laws</a></li> <li><a href="/en/library/process-of-science/49/scientific-controversy/181">Scientific Controversy</a></li> <li><a href="/en/library/process-of-science/49/creativity-in-science/182">Creativity in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-research-methods" data-accordion="button" aria-controls="acc-panel-research-methods" aria-expanded="false"> <span class="accordion__button__label"> Research Methods </span> </button> <div class="accordion__panel" id="acc-panel-research-methods" data-accordion="panel" aria-labelledby="acc-button-research-methods" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/the-practice-of-science/148">The Practice of Science</a></li> <li><a href="/en/library/process-of-science/49/experimentation-in-scientific-research/150">Experimentation in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/description-in-scientific-research/151">Description in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/comparison-in-scientific-research/152">Comparison in Scientific Research</a></li> <li><a href="/en/library/process-of-science/49/modeling-in-scientific-research/153">Modeling in Scientific Research</a></li> </ul> </div> <button class="accordion__button" id="acc-button-data" data-accordion="button" aria-controls="acc-panel-data" aria-expanded="false"> <span class="accordion__button__label"> Data </span> </button> <div class="accordion__panel" id="acc-panel-data" data-accordion="panel" aria-labelledby="acc-button-data" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/data-analysis-and-interpretation/154">Data Analysis and Interpretation</a></li> <li><a href="/en/library/process-of-science/49/uncertainty-error-and-confidence/157">Uncertainty, Error, and Confidence</a></li> <li><a href="/en/library/process-of-science/49/statistics-in-science/155">Statistics in Science</a></li> <li><a href="/en/library/process-of-science/49/using-graphs-and-visual-data-in-science/156">Using Graphs and Visual Data in Science</a></li> </ul> </div> <button class="accordion__button" id="acc-button-scientific-communication" data-accordion="button" aria-controls="acc-panel-scientific-communication" aria-expanded="false"> <span class="accordion__button__label"> Scientific Communication </span> </button> <div class="accordion__panel" id="acc-panel-scientific-communication" data-accordion="panel" aria-labelledby="acc-button-scientific-communication" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/process-of-science/49/understanding-scientific-journals-and-articles/158">Understanding Scientific Journals and Articles</a></li> <li><a href="/en/library/process-of-science/49/utilizing-the-scientific-literature/173">Utilizing the Scientific Literature</a></li> <li><a href="/en/library/process-of-science/49/peer-review-in-scientific-publishing/159">Peer Review in Scientific Publishing</a></li> <li><a href="/en/library/process-of-science/49/the-how-and-why-of-scientific-meetings/186">The How and Why of Scientific Meetings</a></li> </ul> </div> </div> </div> <button class="accordion__button" id="acc-button-scientists-and-research" data-accordion="button" aria-controls="acc-panel-scientists-and-research" aria-expanded="false"> <span class="accordion__button__label"> Scientists and Research </span> </button> <div class="accordion__panel" id="acc-panel-scientists-and-research" data-accordion="panel" aria-labelledby="acc-button-scientists-and-research" role="region"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-button-scientific-research" data-accordion="button" aria-controls="acc-panel-scientific-research" aria-expanded="false"> <span class="accordion__button__label"> Scientific Research </span> </button> <div class="accordion__panel" id="acc-panel-scientific-research" data-accordion="panel" aria-labelledby="acc-button-scientific-research" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/collaborative-research-in-the-arctic-towards-understanding-climate-change/183">Collaborative Research in the Arctic Towards Understanding Climate Change</a></li> <li><a href="/en/library/scientists-and-research/58/from-stable-chromosomes-to-jumping-genes/184">From Stable Chromosomes to Jumping Genes</a></li> <li><a href="/en/library/scientists-and-research/58/an-elegant-experiment-to-test-the-process-of-dna-replication/187">An Elegant Experiment to Test the Process of DNA Replication</a></li> <li><a href="/en/library/scientists-and-research/58/the-founding-of-neuroscience/233">The Founding of Neuroscience</a></li> <li><a href="/en/library/scientists-and-research/58/tracking-endangered-jaguars-across-the-border/189">Tracking Endangered Jaguars across the Border</a></li> <li><a href="/en/library/scientists-and-research/58/atmospheric-chemistry-research-that-changed-global-policy/211">Atmospheric Chemistry Research that Changed Global Policy</a></li> <li><a href="/en/library/scientists-and-research/58/revolutionizing-medicine-with-monoclonal-antibodies/220">Revolutionizing Medicine with Monoclonal Antibodies</a></li> <li><a href="/en/library/scientists-and-research/58/uncovering-the-mysteries-of-chronic-mountain-sickness/238">Uncovering the Mysteries of Chronic Mountain Sickness</a></li> </ul> </div> <button class="accordion__button" id="acc-button-profiles-in-science" data-accordion="button" aria-controls="acc-panel-profiles-in-science" aria-expanded="false"> <span class="accordion__button__label"> Profiles in Science </span> </button> <div class="accordion__panel" id="acc-panel-profiles-in-science" data-accordion="panel" aria-labelledby="acc-button-profiles-in-science" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/scientists-and-research/58/luis-e.-miramontes/232">Luis E. Miramontes</a></li> <li><a href="/en/library/scientists-and-research/58/bernardo-houssay/237">Bernardo Houssay</a></li> <li><a href="/en/library/scientists-and-research/58/craig-lee/256">Craig Lee</a></li> <li><a href="/en/library/scientists-and-research/58/david-ho/241">David Ho</a></li> <li><a href="/en/library/scientists-and-research/58/louis-tompkins-wright/244">Louis Tompkins Wright</a></li> <li><a href="/en/library/scientists-and-research/58/carlos-j.-finlay/217">Carlos J. Finlay</a></li> <li><a href="/en/library/scientists-and-research/58/cecilia-payne/290">Cecilia Payne</a></li> <li><a href="/en/library/scientists-and-research/58/jazmin-scarlett/291">Jazmin Scarlett</a></li> <li><a href="/en/library/scientists-and-research/58/ramari-stewart/292">Ramari Stewart</a></li> <li><a href="/en/library/scientists-and-research/58/johnson-cerda/300">Johnson Cerda</a></li> <li><a href="/en/library/scientists-and-research/58/ellen-ochoa/201">Ellen Ochoa</a></li> <li><a href="/en/library/scientists-and-research/58/ruth-benerito/205">Ruth Benerito</a></li> <li><a href="/en/library/scientists-and-research/58/franklin-chang-díaz/219">Franklin Chang Díaz</a></li> <li><a href="/en/library/scientists-and-research/58/percy-lavon-julian/221">Percy Lavon Julian</a></li> <li><a href="/en/library/scientists-and-research/58/luis-walter-alvarez/229">Luis Walter Alvarez</a></li> <li><a href="/en/library/scientists-and-research/58/france-anne-dominic-córdova/230">France Anne-Dominic Córdova</a></li> </ul> </div> </div> </div> </div> </div> </li> <li>  <button class="button" data-toggle="dropdown">Biology </button> <div class="nav__dropdown box-shadow-1 padding-1"> <div class="accordion accordion--secondary font-size-sm"> <div class="accordion accordion--secondary"> <button class="accordion__button" id="acc-sub-button-biological-molecules" data-accordion="button" aria-controls="acc-sub-panel-biological-molecules" aria-expanded="false"> <span class="accordion__button__label"> Biological Molecules </span> </button> <div class="accordion__panel" id="acc-sub-panel-biological-molecules" data-accordion="panel" aria-labelledby="acc-sub-button-biological-molecules" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/carbohydrates/61">Carbohydrates</a></li> <li><a href="/en/library/biology/2/fats-and-proteins/62">Fats and Proteins</a></li> <li><a href="/en/library/biology/2/biological-proteins/243">Biological Proteins</a></li> <li class="current">Blood Biology I</li> <li><a href="/en/library/biology/2/lipids/207">Lipids</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-cell-biology" data-accordion="button" aria-controls="acc-sub-panel-cell-biology" aria-expanded="false"> <span class="accordion__button__label"> Cell Biology </span> </button> <div class="accordion__panel" id="acc-sub-panel-cell-biology" data-accordion="panel" aria-labelledby="acc-sub-button-cell-biology" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/discovery-and-structure-of-cells/64">Discovery and Structure of Cells</a></li> <li><a href="/en/library/biology/2/respiration/285">Respiration</a></li> <li><a href="/en/library/biology/2/membranes-i/198">Membranes I</a></li> <li><a href="/en/library/biology/2/membranes-ii/204">Membranes II</a></li> <li><a href="/en/library/biology/2/cellular-organelles-i/195">Cellular Organelles I</a></li> <li><a href="/en/library/biology/2/cell-division-i/196">Cell Division I</a></li> <li><a href="/en/library/biology/2/cell-division-ii/212">Cell Division II</a></li> <li><a href="/en/library/biology/2/membranes-and-chemical-transport/106">Membranes and Chemical Transport</a></li> </ul> </div> <button class="accordion__button" id="acc-sub-button-energy-in-living-systems" data-accordion="button" aria-controls="acc-sub-panel-energy-in-living-systems" aria-expanded="false"> <span class="accordion__button__label"> Energy in Living Systems </span> </button> <div class="accordion__panel" id="acc-sub-panel-energy-in-living-systems" data-accordion="panel" aria-labelledby="acc-sub-button-energy-in-living-systems" role="region"> <ul class="nav text-color-link"> <li><a href="/en/library/biology/2/energy-metabolism-i/215">Energy Metabolism I</a></li> <li><a href="/en/library/biology/2/energy-metabolism-ii/225">Energy Metabolism II</a></li> <li><a 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<strong><em>Biological Molecules</em></strong> </span> <h1>Blood Biology I: <sub><em>Components of blood</em></sub></h1> <p class="byline">by David Warmflash, MD, Nathan H Lents, Ph.D.</p> <nav class="module__header__tabs"> <ul class="tabs-nav tabs-nav--horizontal library"> <li> <a href="/en/library/biology/2/blood-biology-i/242/reading" aria-current="page" >Reading</a> </li> <li> <a href="/en/library/biology/2/blood-biology-i/242/quiz">Quiz</a> </li> <li> <a href="/en/library/biology/2/blood-biology-i/242/resources">Teach with this</a> </li> </ul> </nav> </div> </header> <hr class="divider"/>   <div class="grid grid--sidebar-right grid--divider"> <div class="order-2 order-1--lg module__main"> <div class="narrow margin-x-auto margin-y-5"> <div class="accordion margin-bottom-5">  <button class="accordion__button" id="acc-button-key-concepts" data-accordion="button" aria-controls="acc-panel-key-concepts" aria-expanded="true" tabindex="0"> Did you know? </button> <div class="accordion__panel shown show" id="acc-panel-key-concepts" data-accordion="panel" aria-labelledby="acc-button-key-concepts" role="region"> <div class="accordion__panel__content"> <p>Did you know that in the early days of blood transfusions, more people died than survived them? All blood looks pretty much the same to the naked eye, but blood that is lifesaving for one person may be deadly to another. Transfusions became a safe medical procedure only when scientists came to understand the complexity of blood components and different blood types.</p> </div> </div>  <button class="accordion__button" id="acc-button-table-of-contents" data-accordion="button" aria-controls="acc-panel-table-of-contents" aria-expanded="false" tabindex="0"> Key concepts </button> <div class="accordion__panel" id="acc-panel-table-of-contents" data-accordion="panel" aria-labelledby="acc-button-table-of-contents" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <ul class="bulleted"> <li><p>Blood is a complex fluid with many different components, but can be divided into solids (red blood cells, white blood cells, and platelets) and liquid (plasma).</p></li> <li><p>Blood plasma includes clotting factors (agents that help to form blood clots) and when these are removed, the remaining liquid is known as serum.</p></li> <li><p>The main cellular components of blood are: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).</p></li> <li><p>The Austrian researcher Karl Landsteiner studied agglutination, or clumping together of blood cells with certain antigens. Based on his findings, he proposed that there were three types of blood (A, B, O) and later added a fourth type (AB).</p></li> <li><p>Antibodies are proteins produced by plasma cells, a type of B-cell lymphocyte, and are present in the blood serum. These antibodies are important for blood transfusion, since the blood type of a patient and the type of antibodies present in the donor’s blood will determine whether or not it agglutinates or clumps.</p></li> </ul> </div> </div>  <button class="accordion__button" id="acc-button-terms-you-should-know" data-accordion="button" aria-controls="acc-panel-terms-you-should-know" aria-expanded="false" tabindex="0"> Terms you should know </button> <div class="accordion__panel" id="acc-panel-terms-you-should-know" data-accordion="panel" aria-labelledby="acc-button-terms-you-should-know" role="region" aria-hidden="true"> <div class="accordion__panel__content"> <dl> <dt>clotting </dt> <dd> when blood changes from a liquid to a gel, preventing too much bleeding; coagulation </dd> <dt>plasma </dt> <dd> the liquid portion of blood that contains clotting factors but no cells </dd> <dt>platelet </dt> <dd> a cell fragment enclosed in a membrane that helps in blood clotting; thrombocytes </dd> <dt><a href="/en/glossary/view/serum">serum </a></dt> <dd> the liquid portion of blood that lacks clotting factors</dd> </dl> </div> </div> </div> <hr class="border-color-dark" /> <section> <div class="container narrow"> <p>If you’ve ever had blood drawn as part of a routine checkup, or for donation, you probably recall the procedure being very quick and simple. Today, it is routine to collect blood from people, to separate the blood into its various components, to store those components, and then to infuse them into other people. "Packed red blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>," "platelets," and "fresh frozen plasma" are terms that you’d hear all day long if you were to volunteer on a medical ward. Along with saline, blood products are among the most common agents infused into patients. Each day, transfusion saves many lives, and one can hardly imagine modern medicine without it.</p> <p>But it’s one of the most dangerous things that you can do to someone, if you don’t know what you’re doing.</p> <p><section id="toc_1" class=""> <h2>Early blood transfusions</h2></p> <p>In 1628, William Harvey, an English physician, discovered how blood moves through vessels in the body, that it circulates through arteries and <mark class="term" data-term="vein" data-term-def="One of the systems of branching vessels conveying deoxygenated blood from various parts of the body to the heart." data-term-url="/en/glossary/view/vein/5276">veins</mark>, and within just a few years scientists were attempting transfusions. Their rationale was simple and still makes sense today. If somebody is ill, his or her blood could be deficient in something. By giving patients blood from someone else, the deficient component will be replaced and they can get better. By extension, if the patient has a hemorrhage, the deficiency is the quantity of blood itself, so transfusion should also be helpful in this type of patient. It made perfect sense in the 17th century, given the assumption by anatomists of the time that all blood was the same.</p><p>All blood certainly looked the same and in 1665, another English physician, Richard Lower, was able to keep dogs alive with blood transfused from other dogs. In the years that followed, Lower and other researchers even succeeded in transfusing small amounts of blood between different animals, including from lambs to humans. But most transfusion attempts had fatal consequences. Sometimes the dogs, lambs, or humans died of a high fever. Other times, death followed other reactions that the researchers could not understand.</p><p>For two and a half centuries, doctors experimented occasionally with transfusion and continued finding that small amounts of transfused blood sometimes did not harm the recipient and other times was fatal. In rare cases humans could receive blood even from a non-human animal and live, while others would die after receiving blood from another human. Transfusion was like playing Russian roulette, so it was attempted only in desperation.</p><p>In 1881, for instance, the sister of William Stewart Halsted, a 29 year-old New York City surgeon, developed a severe hemorrhage after giving birth. She would have died except that Halstead drew his own blood and injected it immediately into his sister’s <mark class="term" data-term="vein" data-term-def="One of the systems of branching vessels conveying deoxygenated blood from various parts of the body to the heart." data-term-url="/en/glossary/view/vein/5276">vein</mark>. The transfusion saved her life because she and her brother had compatible blood types, although he did not know about blood compatibility at the time. Halsted got lucky with his sister, but science was only years away from unraveling a mystery that would make transfusion safe.</p><p>That research happened at the turn of the 20th century, in connection with work on a phenomenon called <mark class="term" data-term="hemagglutination" data-term-def="The clumping together of red blood cells as a result of antibodies that bind to specific blood group antigens. Hemagglutination is&hellip;" data-term-url="/en/glossary/view/hemagglutination/10445">hemagglutination</mark>. This is a clumping of blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> that researchers were observing in the blood of victims of mismatched experimental transfusions, and it happens because all blood is not the same. Blood has thousands of different components and slight differences in some of them can spell failure if blood or a blood product is given that is inappropriate for the recipient. On the other hand, all blood is similar in its basic components.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc10446"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Early blood transfusions were safe provided that only a small amount of blood was transfused into the person.</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-10446-0-option-a" name="quiz-option-10446" type="radio" value="True" > <span class="option__label"> <span class="screen-reader-only">a.</span> True </span> </label> <span class="quiz__response" id="response-10446-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-10446-1-option-b" name="quiz-option-10446" type="radio" value="False" > <span class="option__label"> <span class="screen-reader-only">b.</span> False </span> </label> <span class="quiz__response" id="response-10446-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_2"> <h2>Whole blood, plasma, and serum</h2><p>If you know anyone who is diabetic, you may have heard something about that person’s blood <mark class="term" data-term="sugar" data-term-def="A water-soluble crystalline carbohydrate. There are many types of sugar of varying degrees of sweetness, including fructose, which occurs naturally in&hellip;" data-term-url="/en/glossary/view/sugar/5309">sugar</mark>, or blood <mark class="term" data-term="glucose" data-term-def="The primary form of sugar stored in the human body for energy: C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>." data-term-url="/en/glossary/view/glucose/8735">glucose</mark>. Glucose is a type of sugar (see our module <a href="/library/module_viewer.php?mid=215">Energy Metabolism I: An introduction</a>). It’s the main source of <mark class="term" data-term="energy" data-term-def="An abstract property defined as the capacity to do work. The basic forms of energy include chemical, electrical, mechanical, nuclear, and&hellip;" data-term-url="/en/glossary/view/energy/1497">energy</mark> in <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>, and since its <mark class="term" data-term="concentration" data-term-def="The amount of one substance in relation to other components within a given area." data-term-url="/en/glossary/view/concentration/8733">concentration</mark> in the blood should not be too high, nor too low, diabetics check their glucose levels frequently. Usually, they do this with a device that requires only a drop of blood. It’s called “whole blood,” because an individual needs only to prick his or her finger to release a drop. Nothing is separated out of the blood sample, so the machine reads the concentration of glucose in blood the way it exists within the body. For other blood tests, though, you may have heard your doctor or nurse mention plasma or <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> levels. On routine exams, they tell you about your serum cholesterol or your serum triglycerides. On other occasions they may mention tests for plasma levels of certain chemicals, or you may have heard of somebody either donating plasma or receiving it.</p><p>In addition to water with numerous dissolved <mark class="term" data-term="compound" data-term-def="A material formed by the chemical combination of elements in defined proportions. Compounds can be chemically decomposed into simpler substances." data-term-url="/en/glossary/view/compound/1517">compounds</mark> such as <mark class="term" data-term="glucose" data-term-def="The primary form of sugar stored in the human body for energy: C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>." data-term-url="/en/glossary/view/glucose/8735">glucose</mark>, blood contains <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. Physicians commonly talk about the blood cells collectively as a <mark class="term" data-term="solid" data-term-def="A collection of atoms or molecules that are held together so that, under constant conditions, they maintain a defined shape and&hellip;" data-term-url="/en/glossary/view/solid/7571">solid</mark> or cellular component of blood, because they can be easily separated from the <mark class="term" data-term="liquid" data-term-def="The state of matter characterized by its condensed nature and ability to flow. Unlike gases, molecules within a liquid often experience&hellip;" data-term-url="/en/glossary/view/liquid/8727">liquid</mark> component. The liquid component is mostly water, but two different “versions” of this liquid can be prepared, depending on how the separation is performed.</p><p>The term plasma refers to everything in the blood without the <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. It is obtained by drawing a blood sample into a tube that has an agent that slows clotting, then spinning the tube in a centrifuge. During spinning, everything in the tube becomes many times heavier than its normal <mark class="term" data-term="weight" data-term-def="A measure of the force exerted on an object by a gravitational field. The weight of an object equals its mass&hellip;" data-term-url="/en/glossary/view/weight/3418">weight</mark> under Earth's <mark class="term" data-term="gravity" data-term-def="The natural force that attracts a body toward the center of the Earth, or toward another physical body having mass." data-term-url="/en/glossary/view/gravity/11223">gravity</mark>. Since blood cells, cell fragments, and very large <mark class="term" data-term="molecule" data-term-def="A particle formed by the chemical bonding of two or more atoms. The molecule is the smallest particle of a&hellip;" data-term-url="/en/glossary/view/molecule/1518">molecules</mark> are denser than water, as they get heavier they move toward the bottom of the tube much faster than they would without spinning. What’s left on top is the plasma. (See Figure 1 for a diagram.) The percentage of whole blood <mark class="term" data-term="volume" data-term-def="The amount of space taken up by matter, commonly expressed in cubic centimeters (cm<sup>3</sup>) or milliliters (ml)." data-term-url="/en/glossary/view/volume/8515">volume</mark> that is packed cells is called the <mark class="term" data-term="hematocrit" data-term-def="The portion of blood made up of red blood cells, measured as the volume percentage of the whole blood." data-term-url="/en/glossary/view/hematocrit/10452">hematocrit</mark> and its value usually correlates with how well a person is making and maintaining hemoglobin and red blood cells (more on that below).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10430.png"> <img src="/img/library/modules/mid242/Image/VLObject-10430-160903010911.png" alt="Figure 1: The average composition of blood. In this example, the blood is shown after spinning in a centrifuge so the different elements are separated: the heavier red blood cells at the bottom, then the white blood cells and platelets in the center, and the plasma at the top. The percentage of red blood cells is also known as hematocrit." /> </button> <figcaption> <p><strong>Figure 1</strong>: The average composition of blood. In this example, the blood is shown after spinning in a centrifuge so the different elements are separated: the heavier red blood cells at the bottom, then the white blood cells and platelets in the center, and the plasma at the top. The percentage of red blood cells is also known as hematocrit.</p> <span class="credit">image ©Pirumbaut</span> </figcaption> </figure> </div> <p>Plasma includes not just water, but also numerous agents called clotting factors that are involved in forming blood clots. In contrast to plasma, <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> lacks many of the clotting factors. Serum is obtained by drawing a blood sample into a tube that is not treated to prevent clotting, but rather designed to encourage clotting. The sample is allowed to sit while it clots over time, thereby consuming most of the clotting factors. Then, the sample is centrifuged and <mark class="term" data-term="liquid" data-term-def="The state of matter characterized by its condensed nature and ability to flow. Unlike gases, molecules within a liquid often experience&hellip;" data-term-url="/en/glossary/view/liquid/8727">liquid</mark> that ends up on the top of the tube, called serum, is free of most clotting factors. Thus, plasma minus clotting factors equals serum (Figure 2).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10453.jpg"> <img src="/img/library/modules/mid242/Image/VLObject-10453-160903120935.jpg" alt="Figure 2: A researcher piping blood serum into a test tube." /> </button> <figcaption> <p><strong>Figure 2</strong>: A researcher piping blood serum into a test tube.</p> <span class="credit">image ©U.S. Air Force/Keenan Berry</span> </figcaption> </figure> </div> <p>In laboratory medicine, the decision on whether to use whole blood, plasma, or <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> for a certain test often involves a tradeoff of various advantages and drawbacks of each. Serum takes longer than plasma to prepare, for instance, and this can be a problem during emergencies or when measuring the <mark class="term" data-term="concentration" data-term-def="The amount of one substance in relation to other components within a given area." data-term-url="/en/glossary/view/concentration/8733">concentration</mark> of a blood chemical that changes rapidly over time. If clotting factors are what you’re trying to measure (in a patient with hemophilia, a disorder where the blood doesn't clot normally, for instance) then you must use plasma, not serum, because the latter lacks clotting factors.</p><p>There are several settings when <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> is preferable, for example the need to measure antibodies in a patient’s blood. The term <mark class="term" data-term="serology" data-term-def="The identification and study of bodily fluids, specifically the serum in blood. Often, researchers use the term serology to refer to&hellip;" data-term-url="/en/glossary/view/serology/10458">serology</mark>, though its literal meaning is the study of serum, often refers to the diagnostic assessment of serum for antibodies.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc10456"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">_____ contains clotting factors.</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-10456-0-option-a" name="quiz-option-10456" type="radio" value="Plasma" > <span class="option__label"> <span class="screen-reader-only">a.</span> Plasma </span> </label> <span class="quiz__response" id="response-10456-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-10456-1-option-b" name="quiz-option-10456" type="radio" value="Serum" > <span class="option__label"> <span class="screen-reader-only">b.</span> Serum </span> </label> <span class="quiz__response" id="response-10456-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_3"> <h2>The discovery of blood types</h2><p>The age of <mark class="term" data-term="serology" data-term-def="The identification and study of bodily fluids, specifically the serum in blood. Often, researchers use the term serology to refer to&hellip;" data-term-url="/en/glossary/view/serology/10458">serology</mark> began in Austria, at the University of Vienna, where physician-researcher, <mark class="term" data-term="Karl Landsteiner" data-term-def="(1868-1943) Austrian forensic researcher and physician who discovered ABO blood types in 1900, thereby enabling safe blood transfusion. Also, together with&hellip;" data-term-url="/en/glossary/view/Landsteiner%2C+Karl/10185">Karl Landsteiner</mark> worked in forensic anatomy (Figure 3). In 1900, Landsteiner noticed that blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cell</mark> clumping, or <mark class="term" data-term="agglutination" data-term-def="The clumping together cells bearing antigens, microorganisms, or particles when in the presence of an antibody. When the clumping involves red&hellip;" data-term-url="/en/glossary/view/agglutination/10461">agglutination</mark>, following mixing of blood samples from different patients released toxins into the blood sample. He started mixing blood from patients, not just with whole blood samples, but also with <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> from other individuals. He observed that when mixed with serum from a different person, blood cells would either clump or not clump, and that the clumps could be either small or large. Because the clumping had to be the result of the cells reacting with something in the serum, Landsteiner wondered if perhaps blood might indeed differ between individuals, an idea that went against the common thinking of his era.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10431.jpg"> <img src="/img/library/modules/mid242/Image/VLObject-10431-160903010919.jpg" alt="Figure 3: Karl Landsteiner (1868-1943), Austrian biologist at the University of Vienna. Landsteiner pioneered research on blood types." /> </button> <figcaption> <p><strong>Figure 3</strong>: Karl Landsteiner (1868-1943), Austrian biologist at the University of Vienna. Landsteiner pioneered research on blood types.</p> <span class="credit">image ©National Academy of Sciences</span> </figcaption> </figure> </div> <p>Landsteiner set up a series of <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> using blood from just six volunteers (himself included), but mixing different blood components in various combinations and careful repetition of each mixing experiment turned those six volunteers into one of the greatest medical discoveries of the early 20th century. Based on his findings, Landsteiner proposed that there were three types or groups of blood that differed by the presence of factors in the <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> that today we call <mark class="term" data-term="antigen" data-term-def="A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and&hellip;" data-term-url="/en/glossary/view/antigen/5280">antigens</mark>. Blood could be mixed between two people, without <mark class="term" data-term="agglutination" data-term-def="The clumping together cells bearing antigens, microorganisms, or particles when in the presence of an antibody. When the clumping involves red&hellip;" data-term-url="/en/glossary/view/agglutination/10461">agglutination</mark>, he said, so long as the people were of the same type. He named the three types "A," "B," and "C" (the latter was eventually changed to "O").</p><p>It was a watershed study that ushered in an era of experimental blood transfusions in hospital settings, leading to the first ABO-matched transfusion, carried out at New York’s Mount Sinai Hospital in 1907. Transfusion could become routine only after physicians gained some understanding of the complexity of <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> and blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. Such an understanding began when Landsteiner defined his blood groups and began systematic <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> aimed at honing in on the causes of <mark class="term" data-term="hemagglutination" data-term-def="The clumping together of red blood cells as a result of antibodies that bind to specific blood group antigens. Hemagglutination is&hellip;" data-term-url="/en/glossary/view/hemagglutination/10445">hemagglutination</mark>. That <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark> would quickly enable a revolution in medicine and especially in surgery.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc10464"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">Blood mixed between two people formed clumps when the people had</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-10464-0-option-a" name="quiz-option-10464" type="radio" value="different blood types." > <span class="option__label"> <span class="screen-reader-only">a.</span> different blood types. </span> </label> <span class="quiz__response" id="response-10464-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-10464-1-option-b" name="quiz-option-10464" type="radio" value="the same blood type." > <span class="option__label"> <span class="screen-reader-only">b.</span> the same blood type. </span> </label> <span class="quiz__response" id="response-10464-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_4"> <h2>Blood cells</h2><p>The cellular components that are separated from plasma or <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> include various types of <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> and cell fragments. The main types are red blood cells (also called erythrocytes), white blood cells (also called leukocytes), and platelets (also called thrombocytes).</p></section> <section id="toc2_1"><h3>Platelets</h3><p>Platelets are actually <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cell</mark> fragments because they are pieces of precursor cells called megakaryocytes that break up during maturation. What is left are tiny pieces, generally 2 microns across, called platelets. Essentially, a platelet is a package enclosed by a <mark class="term" data-term="membrane" data-term-def="A thin layer of tissue that forms a boundary of a cell or cell part." data-term-url="/en/glossary/view/membrane/8282">membrane</mark>. Inside and on the <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark> of the platelet are various clotting factors and other <mark class="term" data-term="protein" data-term-def="Macromolecules that are polymers of individual amino acids arranged in a chain and joined together by peptide bonds (and so also&hellip;" data-term-url="/en/glossary/view/protein/1594">proteins</mark> important to the stopping and prevention of bleeding. Clotting factors are also present in the cells that line blood vessels and, as noted earlier, clotting factors are also dissolved in the blood itself, outside of cells. The clotting factors from all three of these sources come together to stop the bleeding whenever a blood vessel breaks.</p><p>When a blood vessel wall is damaged, a certain <mark class="term" data-term="protein" data-term-def="Macromolecules that are polymers of individual amino acids arranged in a chain and joined together by peptide bonds (and so also&hellip;" data-term-url="/en/glossary/view/protein/1594">protein</mark> called fibrin is exposed that sticks to platelets. This attracts platelets to the injured vessel wall. Not only do platelets stick to the damaged area, but they also become sticky to other platelets. The result is called a platelet plug, which results in hemostasis, or the stopping of bleeding (Figure 4). The most obvious example of this is the scab that forms on your skin when you skin an elbow or knee.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10432.jpg"> <img src="/img/library/modules/mid242/Image/VLObject-10432-160903010928.jpg" alt="Figure 4: The process of hemostasis, or the stopping of blood flow in the body. When a blood vessel wall is injured, platelets stick to the damaged area and they become sticky with other platelets. The result is called a platelet plug, which stops the bleeding." /> </button> <figcaption> <p><strong>Figure 4</strong>: The process of hemostasis, or the stopping of blood flow in the body. When a blood vessel wall is injured, platelets stick to the damaged area and they become sticky with other platelets. The result is called a platelet plug, which stops the bleeding.</p> <span class="credit">image ©ttsz/istockphoto</span> </figcaption> </figure> </div> </section> <section id="toc2_2"><h3>Red blood cells</h3><p>As <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> go, red blood cells (RBCs) are very small - 6-8 microns in diameter. Mature RBCs are filled entirely with the <mark class="term" data-term="protein" data-term-def="Macromolecules that are polymers of individual amino acids arranged in a chain and joined together by peptide bonds (and so also&hellip;" data-term-url="/en/glossary/view/protein/1594">protein</mark> hemoglobin and their job is to transport oxygen in the blood. A person with an abnormally low number of RBCs, or a low <mark class="term" data-term="concentration" data-term-def="The amount of one substance in relation to other components within a given area." data-term-url="/en/glossary/view/concentration/8733">concentration</mark> of hemoglobin in the blood or in RBCs, is said to have anemia. There are many different kinds of anemia, which can result either from reduced production of RBCs or accelerated destruction of RBCs.</p><p>Regardless of the condition that causes it, anemia can vary in its effects from very mild to very severe. When the number of RBCs or the amount of hemoglobin is just slightly below normal a person may feel totally normal, or may feel fatigue only with strenuous activity. But as the anemia worsens, a person will feel very sick and appear pale. With fewer RBCs and/or less hemoglobin, their <mark class="term" data-term="hematocrit" data-term-def="The portion of blood made up of red blood cells, measured as the volume percentage of the whole blood." data-term-url="/en/glossary/view/hematocrit/10452">hematocrit</mark> will be below normal and their muscles fatigue easily, because less oxygen is delivered to the muscle <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. To compensate for the decreased oxygen-carrying ability of the blood, the heart beats faster in order to move more blood, but the decreased ability to carry oxygen also can affect the heart itself.</p><p>RBCs are particularly relevant to Landsteiner’s work on transfusion <mark class="term" data-term="research" data-term-def="A study or an investigation." data-term-url="/en/glossary/view/research/8257">research</mark>, since they comprise most of the cellular component of blood and account for much of what early transfusions provided to recipients. Transfusions in those early years consisted of whole blood, though today RBCs are stored and infused as packed red blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> (PRBCs) in most transfusions. </p></section> <section id="toc2_3"><h3>White blood cells</h3><p>White blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> (WBCs) have their name because they are more of a clear color and are not red since they do not contain hemoglobin. They are bigger than RBCs and are part of the immune <mark class="term" data-term="system" data-term-def="A group of interacting, interrelated or interdependent components that form a complex whole. The size of the system is defined for&hellip;" data-term-url="/en/glossary/view/system/3904">system</mark>. WBCs are classified into two groups: granulocytes and agranulocytes. Each group consists of different subtypes (see Figure 5) and their numbers and proportions are what physicians want to see when they order a complete blood cell count with differential, (often abbreviated as “CBC w/diff”).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10433.png"> <img src="/img/library/modules/mid242/Image/VLObject-10433-160903010937.png" alt="Figure 5: Leukocytes, or white blood cells, are classified into two groups: granular and agranular. Each of these groups are further broken down into different subtypes. (Leukocyte images via "Blausen gallery 2014" in the Wikiversity Journal of Medicine, DOI:10.15347/wjm/2014.010.)" /> </button> <figcaption> <p><strong>Figure 5</strong>: Leukocytes, or white blood cells, are classified into two groups: granular and agranular. Each of these groups are further broken down into different subtypes. (Leukocyte images via "Blausen gallery 2014" in the Wikiversity Journal of Medicine, DOI:10.15347/wjm/2014.010.)</p> <span class="credit">image ©BruceBlaus</span> </figcaption> </figure> </div> <p>Granulocytes are WBCs that show granules, little dots in their <mark class="term" data-term="cytoplasm" data-term-def="A clear, water-based gel that contains enzymes, salts, and organic molecules. In eukaryotic cells, cytoplasm surrounds the nucleus and organelles. The&hellip;" data-term-url="/en/glossary/view/cytoplasm/2570">cytoplasm</mark>, when viewed under a microscope. They are thus called "granular." The dots are secretory <mark class="term" data-term="vesicle" data-term-def="A small, self-enclosed sac inside of cells containing fluid and other material. The vesicles organize the cell's metabolism, help store enzymes&hellip;" data-term-url="/en/glossary/view/vesicle/2610">vesicles</mark> filled with various <mark class="term" data-term="enzyme" data-term-def="Molecules produced by living organisms that help catalyze biochemical reactions. Enzymes are predominantly protein or protein-based molecules and are highly&hellip;" data-term-url="/en/glossary/view/enzyme/1595">enzymes</mark> and other <mark class="term" data-term="compound" data-term-def="A material formed by the chemical combination of elements in defined proportions. Compounds can be chemically decomposed into simpler substances." data-term-url="/en/glossary/view/compound/1517">compounds</mark> that vary among three types of granulocytes that exist in blood:</p><p><strong>Neutrophils</strong> are the most abundant type of WBC, accounting for 40-70 percent of all WBCs. They are much bigger than RBCs and also very short-lived. While RBCs live in the blood an <mark class="term" data-term="average" data-term-def="In statistics, average commonly refers to the arithmetic mean, also called simply "mean," which is one measure of the mid-point of&hellip;" data-term-url="/en/glossary/view/average/8542">average</mark> of 120 days, a typical <mark class="term" data-term="neutrophil" data-term-def="The most abundant type of white blood cell in vertebrates." data-term-url="/en/glossary/view/neutrophil/10189">neutrophil</mark> lives only for 6-10 hours. The function of neutrophils is to eat up <mark class="term" data-term="bacteria" data-term-def="(plural of bacterium) A large group of one-celled organisms that are found almost everywhere." data-term-url="/en/glossary/view/bacteria/8679">bacteria</mark> and damaged tissue. They do this by releasing from their granules <mark class="term" data-term="enzyme" data-term-def="Molecules produced by living organisms that help catalyze biochemical reactions. Enzymes are predominantly protein or protein-based molecules and are highly&hellip;" data-term-url="/en/glossary/view/enzyme/1595">enzymes</mark> that break down the bacteria and cytokines, which amplify the antibacterial response, partly by telling the body to manufacture still more neutrophils. On account of this function, neutrophils are produced more rapidly than usual when the body is fighting a bacterial infection and the number of neutrophils in the blood can rise quickly and dramatically. Because they are so short-lived, the neutrophil count also drops quickly when the infection is brought under control. Thus, because neutrophils are the most abundant WBC and because they are so short-lived, the neutrophil count is a very good <mark class="term" data-term="indicator" data-term-def="A substance that, when added to an aqueous solution, has a color determined by the pH. If reactant is added&hellip;" data-term-url="/en/glossary/view/indicator/12228">indicator</mark> for determining whether a patient has an infection.</p><p>The other two types of granulocytes are called <u>basophils</u> and <u>eosinophils</u>. The function of basophils is to escalate the body’s inflammatory reaction and have been implicated in allergies. Their granules contain an anticoagulant called heparin and special compounds called histamines, which cause blood vessels to dilate (become wider). Eosinophils fight multicellular <mark class="term" data-term="parasite" data-term-def="An organism that lives on or in a host organism of another species. Parasites derive their food from and are detrimental&hellip;" data-term-url="/en/glossary/view/parasite/5272">parasites</mark> such as hookworms and tapeworms and so their granules contain <mark class="term" data-term="enzyme" data-term-def="Molecules produced by living organisms that help catalyze biochemical reactions. Enzymes are predominantly protein or protein-based molecules and are highly&hellip;" data-term-url="/en/glossary/view/enzyme/1595">enzymes</mark> that are particularly effective against these <mark class="term" data-term="organism" data-term-def="Any connected living system, such as an animal, plant, fungus, or bacterium. Organisms may be composed of a single cell or&hellip;" data-term-url="/en/glossary/view/organism/2171">organisms</mark>.</p><p>Agranulocytes are WBCs that do not show granules when viewed under a microscope, and they come in two subtypes. (Hence, they are "agranular.")</p><p><strong>Monocytes</strong> account for 2-10 percent of WBCs, making them the third-most abundant WBC after <mark class="term" data-term="neutrophil" data-term-def="The most abundant type of white blood cell in vertebrates." data-term-url="/en/glossary/view/neutrophil/10189">neutrophils</mark> and <mark class="term" data-term="lymphocyte" data-term-def="Second most abundant type of white blood cell in the blood of vertebrates." data-term-url="/en/glossary/view/lymphocyte/10186">lymphocytes</mark>. Monocytes circulate in the bloodstream and then move into other tissues when an infection is detected. When they arrive at the infection site, they transform into another type of <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cell</mark>, usually a macrophage, and begin to engulf and digest <mark class="term" data-term="bacteria" data-term-def="(plural of bacterium) A large group of one-celled organisms that are found almost everywhere." data-term-url="/en/glossary/view/bacteria/8679">bacteria</mark>, dead or dying cells, and other infectious material. Some monocytes migrate into bones where they transform into special bone cells called osteoclasts, whose function is to degrade calcified parts of the bone. This is important in the bone remodeling <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark> by which the bone changes its shape in response to stress and exercise, but it also happens in certain bone diseases, such as osteoporosis.</p><p><strong>Lymphocytes</strong> are the second most abundant type of WBCs, accounting for 20-50% of the WBC count. They are subdivided into B-lymphocytes and T-lymphocytes (aka, B-cells and T-cells), each of which is yet further divided into various subtypes. The role of B-cells is to produce antibodies, which attach to agents that the body’s immune <mark class="term" data-term="system" data-term-def="A group of interacting, interrelated or interdependent components that form a complex whole. The size of the system is defined for&hellip;" data-term-url="/en/glossary/view/system/3904">system</mark> considers foreign. This helps to defend the body against infection. However, it can also lead to problems when antibodies are made against an individual’s own tissue, or against something else that benefits the individual, such as a tissue or organ transplant. T-cells are involved in cell-mediated <mark class="term" data-term="immunity" data-term-def="Resistance against infection by a particular disease; the body’s ability to protect against a particular infectious disease." data-term-url="/en/glossary/view/immunity/8745">immunity</mark>, fighting against infections from viruses and <mark class="term" data-term="bacteria" data-term-def="(plural of bacterium) A large group of one-celled organisms that are found almost everywhere." data-term-url="/en/glossary/view/bacteria/8679">bacteria</mark>, and may help the body attack cancer.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc10485"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">To determine if a patient has an infection, a doctor may take a _____ count.</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-10485-0-option-a" name="quiz-option-10485" type="radio" value="red blood cell" > <span class="option__label"> <span class="screen-reader-only">a.</span> red blood cell </span> </label> <span class="quiz__response" id="response-10485-0"> <strong>Incorrect.</strong> </span> </div> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-10485-1-option-b" name="quiz-option-10485" type="radio" value="neutrophil" > <span class="option__label"> <span class="screen-reader-only">b.</span> neutrophil </span> </label> <span class="quiz__response" id="response-10485-1"> <strong>Correct!</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_5"> <h2>Rejection of blood</h2><p>A good example of B-cells making antibodies against foreign tissue is the reaction of blood transfusion recipients to donor blood of a different type. Prior to the late 19th century, nobody had a clue as to why a transfusion would succeed or fail because, as noted earlier, they assumed all blood to be identical. But with improvements in the microscope and in the dyes used to stain <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>, this view started to change. In the years prior to Landsteiner’s discovery, pathologists could see that RBCs were not always exactly the same. Sometimes RBCs would look slightly bigger or smaller than usual, or would stain darker or lighter. They wondered whether these observable differences might have something to do transfusion <mark class="term" data-term="outcome" data-term-def="Result." data-term-url="/en/glossary/view/outcome/8247">outcomes</mark>, but they had not devised a way to test the idea.</p><p>Even with the hand-cranked centrifuges available in those days, Landsteiner could separate the <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> from the <mark class="term" data-term="liquid" data-term-def="The state of matter characterized by its condensed nature and ability to flow. Unlike gases, molecules within a liquid often experience&hellip;" data-term-url="/en/glossary/view/liquid/8727">liquid</mark> in blood fairly easily. That produced plasma, and after separating it from the cells, Landsteiner could keep the cells alive for short periods by suspending them in saline (salt water). He found that mixing cells with plasma would cause clotting, even when the plasma and cells were from the same volunteer. However, if a blood sample was left to clot prior to <mark class="term" data-term="centrifugation" data-term-def="The process of uses a rotating force to separate particles according to density." data-term-url="/en/glossary/view/centrifugation/8514">centrifugation</mark>, the resulting liquid extract did not cause clotting of fresh RBCs from the same volunteer. That’s because the liquid extract was <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark>; it lacked clotting factors because the clotting factors had been consumed before Landsteiner had separated out the liquid.</p><p>Landsteiner did not know about the clotting factors, but he could deduce that <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> and plasma must be different, and this led him to ask a question: What would happen if serum from one volunteer were mixed with saline-suspended RBCs from other volunteers? As happens often in science, a simple question would prove to be the key, since it was a question that Landsteiner was equipped to answer. He needed only to take blood from himself and five other volunteers, extract several samples of serum and blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>, mix the samples in various combinations, and observe the <mark class="term" data-term="mixtures" data-term-def="two or more pure substances combined that retain their unique properties. Mixtures include homogeneous mixtures, also called or solutions, where one&hellip;" data-term-url="/en/glossary/view/mixtures/12622">mixtures</mark> both with the naked eye and a microscope. </p><p>Certain donor <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> samples mixed with blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> from other donors resulted in no <mark class="term" data-term="hemagglutination" data-term-def="The clumping together of red blood cells as a result of antibodies that bind to specific blood group antigens. Hemagglutination is&hellip;" data-term-url="/en/glossary/view/hemagglutination/10445">hemagglutination</mark>. However, serum from those same samples would agglutinate cells from the other donors. Landsteiner also found that some of the volunteer samples could be mixed with one another with no <mark class="term" data-term="agglutination" data-term-def="The clumping together cells bearing antigens, microorganisms, or particles when in the presence of an antibody. When the clumping involves red&hellip;" data-term-url="/en/glossary/view/agglutination/10461">agglutination</mark>. (See Figure 6 for a visual chart of the results.) The presence or absence of hemagglutination sorted the six <mark class="term" data-term="subject" data-term-def="A person or animal used in a research study." data-term-url="/en/glossary/view/subject/8252">subjects</mark> into three categories that Landsteiner called blood groups.</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10434.jpg"> <img src="/img/library/modules/mid242/Image/VLObject-10434-160903010946.jpg" alt="Figure 6: This table illustrates the results of Karl Landsteiner's 1901 experiment using his research group as subjects. Landsteiner mixed the blood cells and sera of his employees and, using a microscope, observed whether there was clumping." /> </button> <figcaption> <p><strong>Figure 6</strong>: This table illustrates the results of Karl Landsteiner's 1901 experiment using his research group as subjects. Landsteiner mixed the blood cells and sera of his employees and, using a microscope, observed whether there was clumping.</p> <span class="credit">image ©Biologie/Schulbuch-O-Mat</span> </figcaption> </figure> </div> <p>Further testing showed that one group differed more from the other two, more than those two differed from one another. When exposed to blood <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> from the two other groups together, <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> from one group of donors would form very big clumps, whereas serum from the other two groups would form only small clumps when exposed to cells from the two other groups together. To explain the results, Landsteiner reasoned that the cells from the volunteers differed in chemical agents present on the cell's <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark>. He called these chemical agents "haptens." Today they are called <mark class="term" data-term="antigen" data-term-def="A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and&hellip;" data-term-url="/en/glossary/view/antigen/5280">antigens</mark> and we know that they’re present not just on RBCs, but also on the <mark class="term" data-term="membrane" data-term-def="A thin layer of tissue that forms a boundary of a cell or cell part." data-term-url="/en/glossary/view/membrane/8282">membranes</mark> of all our cells.</p><p>Landsteiner named the smaller clumping groups A and B and reasoned that the <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> from each must be reacting to the presence of just one hapten that was not its own. When it came to the third group, however, which he first called C (later changed to O), Landsteiner reasoned that their serum must be reacting to the presence of two foreign haptens, thereby resulting in stronger <mark class="term" data-term="hemagglutination" data-term-def="The clumping together of red blood cells as a result of antibodies that bind to specific blood group antigens. Hemagglutination is&hellip;" data-term-url="/en/glossary/view/hemagglutination/10445">hemagglutination</mark>. Group C donors, he suggested, must have no haptens on their RBCs. Thus, when serum from a type A donor is mixed with B and C <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>, it reacts only to the cells of type B donors, whose RBCs have a type B hapten. Similarly, he said that group B serum reacted to cells from group A donors, because those cells possessed type A haptens. In contrast, he proposed, for type C individuals haptens A and B were both foreign, so their <mark class="term" data-term="serum" data-term-url="/en/glossary/view/serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;">sera</mark> reacted more strongly. </p><p>Using multiple samples from blood drawn over several weeks from all six volunteers, Landsteiner repeated the <mark class="term" data-term="experiment" data-term-def="A test or trial carried out under controlled conditions so that specific actions can be performed and the results can be observed." data-term-url="/en/glossary/view/experiment/8292">experiments</mark> and found that grouping pattern always came out the same. Once that was certain, he published the findings with his proposal that the success or failure of transfusion depended on the A/B haptens, but a study of just six <mark class="term" data-term="subject" data-term-def="A person or animal used in a research study." data-term-url="/en/glossary/view/subject/8252">subjects</mark> did not provide enough confidence for anyone to attempt a transfusion in humans based on the experimental results. More <mark class="term" data-term="data" data-term-def="(plural form of <b>datum</b>) A collection of pieces of information, generally taking the form of numbers, text, bits, or facts, that&hellip;" data-term-url="/en/glossary/view/data/3729">data</mark> were needed, and Landsteiner knew it.</p><p>He had two of his trainees/assistants recruit twenty-two additional blood donors and repeat the <mark class="term" data-term="process" data-term-def="Method, procedure; series of actions or steps." data-term-url="/en/glossary/view/process/8256">process</mark> that they had used on the original six. It’s fortunate that they did, because in 1902 <mark class="term" data-term="analysis" data-term-def="The careful study of data to look for patterns." data-term-url="/en/glossary/view/analysis/8553">analysis</mark> of the results from the expanded study led the team to define a fourth blood type. They called it "AB" since it consisted of people whose RBCs had both <mark class="term" data-term="antigen" data-term-def="A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and&hellip;" data-term-url="/en/glossary/view/antigen/5280">antigens</mark>; their <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark> would agglutinate if mixed with any <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark> but their own type, but their serum would not cause <mark class="term" data-term="agglutination" data-term-def="The clumping together cells bearing antigens, microorganisms, or particles when in the presence of an antibody. When the clumping involves red&hellip;" data-term-url="/en/glossary/view/agglutination/10461">agglutination</mark> in cells of any type (Figure 7).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10435.png"> <img src="/img/library/modules/mid242/Image/VLObject-10435-160903020904.png" alt="Figure 7: ABO blood groups and the antibodies and antigens present in each. This chart tells us that, for example, people with type A blood have the A antigen on the surface of their red cells and anti-B antibodies in their plasma. So if type B blood is mixed with this type A blood, the type A will attack the type B blood by agglutinating the introduced red cells. The same is true if type AB blood is added, but type O will not result in agglutination since it lacks the anti-B antigens on the cell surface." /> </button> <figcaption> <p><strong>Figure 7</strong>: ABO blood groups and the antibodies and antigens present in each. This chart tells us that, for example, people with type A blood have the A antigen on the surface of their red cells and anti-B antibodies in their plasma. So if type B blood is mixed with this type A blood, the type A will attack the type B blood by agglutinating the introduced red cells. The same is true if type AB blood is added, but type O will not result in agglutination since it lacks the anti-B antigens on the cell surface.</p> <span class="credit">image ©InvictaHOG</span> </figcaption> </figure> </div> <p>After a few more years of testing samples from an increasing number of volunteers, Landsteiner and a growing association of colleagues were confident that all humans must fit into the A, B, O, or AB group, and this is what led to the successful 1907 transfusion at Mount Sinai in New York. Leading the Mount Sinai team was Landsteiner’s colleague, Reuben Ottenberg. Like Landsteiner, Ottenberg hailed from Vienna and both were at the beginning of careers that would last a half-century and enable medicine and surgery to advance more in a few decades than it had in all the previous ages of human civilization.</p> <div class="comprehension-checkpoint margin-y-4"> <h6 class="comprehension-checkpoint__header"> <span> <span class="icon icon-question"></span> </span> Comprehension Checkpoint </h6> <form class="" name="cc10496"> <div class="form-entry"> <div class="form-entry__field"> <span class="form-entry__field__label">What Landsteiner called haptens we now call</span> <div class="form-entry__option"> <div class="form-entry__option__radio" data-answer="correct"> <label> <input id="q1-10496-0-option-a" name="quiz-option-10496" type="radio" value="antigens." > <span class="option__label"> <span class="screen-reader-only">a.</span> antigens. </span> </label> <span class="quiz__response" id="response-10496-0"> <strong>Correct!</strong> </span> </div> <div class="form-entry__option__radio" data-answer="incorrect"> <label> <input id="q1-10496-1-option-b" name="quiz-option-10496" type="radio" value="RBCs." > <span class="option__label"> <span class="screen-reader-only">b.</span> RBCs. </span> </label> <span class="quiz__response" id="response-10496-1"> <strong>Incorrect.</strong> </span> </div> </div> </div> </div> </form> </div> </section> <section id="toc_6"> <h2>Antibodies: The key to blood compatibility</h2><p>As for why the various <mark class="term" data-term="serum" data-term-url="/en/glossary/view/serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;">sera</mark> reacted this way to Landsteiner’s "haptens," scientists eventually worked out that the reason was antibodies. Also known as immunoglobulins, antibodies are <mark class="term" data-term="protein" data-term-def="Macromolecules that are polymers of individual amino acids arranged in a chain and joined together by peptide bonds (and so also&hellip;" data-term-url="/en/glossary/view/protein/1594">proteins</mark> produced by a type of B-lymphocyte called plasma <mark class="term" data-term="cell" data-term-def="The basic structural unit of all living things." data-term-url="/en/glossary/view/cell/8286">cells</mark>. While some antibodies circulate attached to the <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark> of the cells that make them, other antibodies detach and float freely in the blood. Thus, they are present in <mark class="term" data-term="serum" data-term-def="(Plural: sera) The liquid portion of whole blood after other material (cells and clotting factors) are removed. Blood serum does contain&hellip;" data-term-url="/en/glossary/view/serum/10459">serum</mark>.</p><p>A person in blood group A does not make antibodies against <mark class="term" data-term="antigen" data-term-def="A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and&hellip;" data-term-url="/en/glossary/view/antigen/5280">antigen</mark> A, but they do make antibodies against antigen B, and thus against RBCs from group B donors. With blood group B, the scenario is the opposite; they make antibodies against antigen A and thus against RBCs from group A donors. People in blood group O (what Landsteiner called group C) make antibodies against both A and B antigens, because both antigens are foreign to them, while people in group AB do not make antibodies against either antigen (Figure 8).</p> <div class="figure"> <figure> <button class="lightbox-button lightbox-button--icon" data-lightbox="" data-lightbox-src="/img/library/large_images/image_10436.png"> <img src="/img/library/modules/mid242/Image/VLObject-10436-160903020909.png" alt="Figure 8: The compatibility of different blood types." /> </button> <figcaption> <p><strong>Figure 8</strong>: The compatibility of different blood types.</p> <span class="credit">image ©InvictaHOG</span> </figcaption> </figure> </div> <p>Landsteiner’s discovery of the ABO groups eliminated the Russian roulette quality that had characterized blood transfusion over the centuries – up to and including Halsted’s courageous but lucky experience in transfusing his hemorrhaging sister. After Ottenberg’s transfusion milestone in 1907, surgeons knew that they could replace lost blood without killing the blood recipient. This allowed them to develop a multitude of new operations that otherwise would have been impossible. Medicine changed profoundly and Landsteiner would be awarded the <mark class="term" data-term="Nobel Prize" data-term-def="Awards made annually, beginning in 1901, from funds originally established by Alfred B. Nobel for outstanding achievement in physics, chemistry, medicine&hellip;" data-term-url="/en/glossary/view/Nobel+Prize/3843">Nobel Prize</mark> in Physiology and Medicine in 1930.</p><p>This was not the end of the story, however, either for Landsteiner or his colleague Ottenberg. For the bulk of the population, ABO grouping alone worked well enough, but by the 1930s the understanding of blood was growing still more complex. One reason for this was another <mark class="term" data-term="surface" data-term-def="The outside or external part; the topside face of something." data-term-url="/en/glossary/view/surface/8275">surface</mark> <mark class="term" data-term="antigen" data-term-def="A substance that stimulates the production of an antibody by the immune system. Antigens include toxins, bacteria, foreign blood cells, and&hellip;" data-term-url="/en/glossary/view/antigen/5280">antigen</mark> on RBCs that also could come into play when blood mixed. It’s called the Rh factor and both Landsteiner and Ottenberg would be central to its discovery. Another reason was that scientists would also come to understand the genetic basis underlying the existence of the RBC antigens.</p> </div> </section> <hr class="border-color-dark" /> <footer class="module__footer"> <p class="citation"> <em> David Warmflash, MD, Nathan H Lents, Ph.D. “Blood Biology I” Visionlearning Vol. BIO-4 (8), 2016. </em> </p>  <div class="title-list" name="further"> <p class="h6 title-list__title"> Further Reading </p> <ul class="grid grid--column-2--md grid--column-3--md gap-1"> <li> <a class="no-hover-focus height-100" href="/en/library/Biology/2/Energy-Metabolism-I/215"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_215-23061209062934.jpeg" alt="Energy Metabolism I"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Energy Metabolism I: <em>Glycolosis and the Krebs cycle</em> </h2> </div> </article> </a> </li> <li> <a class="no-hover-focus height-100" href="/en/library/Biology/2/Membranes-I/198"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_198-23061209062656.jpeg" alt="Membranes I"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Membranes I: <em>Structure and function of biological membranes</em> </h2> </div> </article> </a> </li> <li> <a class="no-hover-focus height-100" href="/en/library/Biology/2/Membranes-II/204"> <article class="flex-row align-items-center flex-column--md align-items-start--md height-100 theme-light padding-2 gap-2"> <div class="width-30 width-auto--md"> <img class="border-radius box-shadow-1" src="/img/library/moduleImages/featured_image_204-23061209062709.jpg" alt="Membranes II"> </div> <div class="flex-grow-shrink"> <h2 class="h6 font-weight-normal"> Membranes II: <em>Passive and active transporters</em> </h2> </div> </article> </a> </li> </ul> </div> </footer> </div>   </div>  <div class="order-1 order-2--lg module__tools"> <div class="narrow margin-x-auto position-sticky-top font-size-md"> <div class="padding-2 border-radius box-shadow-1--lg"> <div class="tabs" role="tablist"> <nav> <button class="button button--icon-label" id="tab-button-in-this-module" aria-label="Table of Contents" aria-controls="tab-panel-module__tools" aria-selected="true" role="tab"> <span class="icon icon-list" aria-hidden="true"></span> <span class="button__text">Contents</span> </button> <button class="button button--icon-label" id="tab-button-toggle-terms" aria-controls="tab-panel-toggle-terms" aria-selected="false" role="tab"> <span class="icon icon-glossary-highlight"></span> <span class="button__text">Glossary Terms</span> </button> </nav> <hr class="divider" /> <div class="tabs__panel shown" id="tab-panel-module__tools" aria-labelledby="tab-button-module__tools" role="tabpanel"> <p class="font-weight-bold margin-bottom-1"> Table of Contents </p> <div class="table-of-contents" id="module-toc"> <ul> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_1">Early blood transfusions</a> </li> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_2">Whole blood, plasma, and serum</a> </li> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_3">The discovery of blood types</a> </li> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_4">Blood cells</a> </li> <li> <ul> <li><a href="/en/library/biology/2/blood-biology-i/242#toc2_1">Platelets</a> </li> </ul> </li> <li> <ul> <li><a href="/en/library/biology/2/blood-biology-i/242#toc2_2">Red blood cells</a> </li> </ul> </li> <li> <ul> <li><a href="/en/library/biology/2/blood-biology-i/242#toc2_3">White blood cells</a> </li> </ul> </li> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_5">Rejection of blood</a> </li> <li><a href="/en/library/biology/2/blood-biology-i/242#toc_6">Antibodies: The key to blood compatibility</a> </li> </ul> </div> </div>   <div class="tabs__panel" id="tab-panel-toggle-terms" aria-labelledby="tab-button-toggle-terms" role="tabpanel"> <div class="reading-toggle"> <div class="reading-toggle__switch"> <div class="form-entry__option__switch"> <label> <input type="checkbox" name="termsToggleSwitch" id="terms-toggle-switch" /> <span class="switch__slider"></span> <span class="option__label text-decoration-none font-size-md"> Highlight Glossary Terms </span> </label> </div> </div> <div class="reading-toggle__help"> <p> <em> Activate glossary term highlighting to easily identify key terms within the module. 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Blood Biology I | Biology | Visionlearning