Introduction - The University of Alabama at Birmingham | UAB



IntroductionThe cardiovascular system functions as asystem to transport numerous substancesthroughout the body such as:NutrientsOxygen and carbon dioxideEnzymes and hormones Ions Transports metabolic wastes to the kidneysTransports leukocytes to aid in fighting infectious agentsIntroductionOther functions of the cardiovascular system are:Stabilization of body temperaturePrevention of the loss of body fluids via the clotting processStabilization of pH and electrolyte balanceFunctions and Composition of the BloodBlood consists of two componentsPlasmaLiquid matrix of bloodFormed elementsBlood cells and cell fragments that are suspended in the plasma, and include:Erythrocytes (red blood cells): transport oxygen and carbon dioxideLeukocytes (white blood cells): function in the immune systemPlatelets: involved in blood clottingFunctions and Composition of the BloodWhole blood consists of:Plasma, erythrocytes, leukocytes, plateletsWhole blood can be fractionated to form:Plasma Packed cells Platelets Packed cells consists of:Mostly erythrocytesFunctions and Composition of the BloodWhole Blood Males: 4–6 litersFemales: 4–5 litersHypovolemic: low blood volumesNormovolemic: normal blood volumesHypervolemic: excessive blood volumespH: 7.35–7.45Functions and Composition of the BloodPlasmaMakes up about 55 percent of the volume of whole bloodConsists of:92 percent water7 percent proteins Albumin, globulins, fibrinogen, regulatory proteins1 percent other solutes Electrolytes, organic nutrients, organic wasteFunctions and Composition of the BloodDifferences between Plasma and Interstitial FluidDissolved oxygen in plasmaConcentration is higher than in interstitial fluidTherefore, oxygen diffuses into the tissuesCarbon dioxide concentration in plasmaConcentration is lower than in interstitial fluidTherefore, carbon dioxide diffuses out of the tissuesPlasma consists of dissolved proteinInterstitial fluid does not have dissolved proteinFunctions and Composition of the BloodThe Plasma ProteinsProduced mainly by the liverMakes up about 7 percent of the plasmaConsists of three major classes of proteinAlbumins (60 percent)Globulins (35 percent)Fibrinogens (4 percent)Functions and Composition of the BloodThe Plasma ProteinsAlbumins (smallest of the plasma proteins)Contribute to the osmotic pressure of plasmaTransport fatty acids and steroid hormones GlobulinsTwo major typesImmunoglobulins: attack pathogensTransport globulins: transport ions and hormones Fibrinogens (largest of the plasma proteins)Involved in blood clotting processesFormed ElementsFormed ElementsMakes up about 45 percent of whole bloodPlatelets (<0.1 percent of whole blood)Leukocytes (<0.1 percent of whole blood)Neutrophils (50–70 percent of the WBCs)Eosinophils (2–4 percent of the WBCs)Basophils (<1 percent of the WBCs)Lymphocytes (20–30 percent of the WBCs)Monocytes (2–8 percent of the WBCs)Erythrocytes (99.9 percent of whole blood)Formed ElementsRed Blood Cells (RBCs) or ErythrocytesHematocrit readingsAlso called packed cell volume (PCV)Also called volume of packed red cells (VPRC)Defined as the percentage of whole blood occupied by the formed elementsMales: 45 percent (5.4 million RBCs per microliter)Females: 42 percent (4.8 million RBCs per microliter)Formed ElementsRed Blood Cells (RBCs) or ErythrocytesOne microliter (or cubic millimeter) of blood consists of millions of RBCsMale: 5.4 million per cubic millimeterFemale: 4.8 million per cubic millimeterFormed ElementsStructure of RBCsBiconcave discThin central regionMeasure about 7.7 microns in diameterLack cell organellesLack a nucleus (anucleated)Contain hemoglobinFormed ElementsRBC Life Span and CirculationCirculating RBCs lack: A nucleus All organellesDue to the lack of a nucleus and organelles, the life span is only about:120 daysFormed ElementsRBC Life Span and CirculationSignificance of a lack of a nucleus:Allows the cell to be flexible as it travels through the circulatory systemAllows for more room for hemoglobinSignificance of a lack of mitochondria:Mitochondria use oxygen to manufacture ATPWithout mitochondria, oxygen can be transported to the tissues instead of being “used” by the mitochondriaFormed ElementsRBCs and HemoglobinA developing erythrocyte loses its nucleus andorganellesA mature erythrocyte is mainly a cell membrane surrounding water and proteinThe water accounts for 66 percent of the RBC’s volumeThe protein accounts for 33 percent of the RBC’s volume of which >95 percent is hemoglobinHemoglobin is responsible for transporting oxygen and carbon dioxide (the main function of RBCs)280 million molecules of hemoglobin per RBCFormed ElementsRBCs and HemoglobinConsists of four polypeptide subunitsTwo alpha chainsTwo beta chainsEach subunit contains a molecule of hemeHeme is a porphyrin ringEach heme consists of an iron ionIron binds to oxygenThe polypeptide units bind to carbon dioxideOxygen and carbon dioxide do not compete with each other for binding sites Formed ElementsBlood TypesBlood types are determined by the antigens on the surface of the erythrocytesAlso known as agglutinogensThese agglutinogens are either glycoproteins or glycolipidsIn the plasma of blood are proteins called antibodiesAlso known a agglutininsFormed ElementsBlood TypesThere are three major types of agglutinogensAgglutinogen AAgglutinogen BAgglutinogen DThere are two major types of agglutininsAgglutinin aAgglutinin bFormed ElementsBlood Types (continued)People with type A blood have:A agglutinogen on the RBCb agglutinin in the plasmaPeople with type B blood have:B agglutinogen on the RBC a agglutinin in the plasmaFormed ElementsBlood Types (continued)People with type AB blood have:Agglutinogen A and agglutinogen B on the RBCNo agglutinin in the plasmaPeople with type O blood have:Neither agglutinogen A nor B on the RBCBoth types of agglutinins in the plasma (a and b)Formed ElementsBlood DonationsType B (packed cells) donor cannot donate to type A patientThe B agglutinogen of the donor will activate the b agglutinin in the plasma of the type A patientAgglutination will occurThis is not a safe donationFormed ElementsBlood Donations (continued)Type AB (packed cells) donor cannot donate to type B patientThe A agglutinogen of the donor will activate the a agglutinin in the plasma of the type B patientAgglutination will occurThis is not a safe donationFormed ElementsBlood Donations (continued)Type B (packed cells) donor can donate to type AB patientThe B agglutinogen of the donor will not activate any agglutinins of the patient because the patient does not have any agglutinins in their plasmaAgglutination will not occurThis is a safe donationFormed ElementsBlood Donations (continued)Type B (whole blood) donor cannot donate to type A patientThe B agglutinogen of the donor will activate the b agglutinin in the plasma of the type A patientThe a agglutinin of the donor will be activated by the A agglutinogen of the patientAgglutination will occurThis is not a safe donationFormed ElementsBlood Donations (continued)Type AB (whole blood) donor cannot donate to type B patientThe A agglutinogen of the donor will activate the a agglutinin in the plasma of the type B patientAgglutination will occurThis is not a safe donationFormed ElementsBlood Donations (continued)Type B (whole blood) donor cannot donate to type AB patientThe B agglutinogen of the donor will not activate any agglutinins of the patient because the patient does not have any agglutinins; however:The A agglutinogen of the patient will activate the a agglutinin from the donorAgglutination will occurThis is not a safe donationFormed ElementsBlood Donations (continued)Type O (packed cells) donor can donate to type B patientThe type O donor does not have any agglutinogens to activate the a agglutinin in the plasma of the patientThis is a safe donationFormed ElementsBlood Donations (continued)Type O (whole blood) donor cannot donate to type B patientThe type O donor is also donating the a and b agglutininsThe B agglutinogen of the patient will activate the b agglutinins from the plasma of the type O donorThis is not a safe donationFormed ElementsLeukocytes There are two major classes of leukocytes consisting of a total of five major types of leukocytesGranulocytes: Neutrophils, eosinophils, basophilsAgranulocytes:Monocytes, lymphocytesFormed ElementsLeukocytes (continued)There are 6000 to 9000 per microliter of bloodA total WBC count is performed on an instrument called a hemocytometerA low count is called leukopeniaAn elevated count is called leukocytosisA differential count is performed to determine which of the leukocytes is in excess or deficient Formed ElementsLeukocytes (continued)Have a short life span (usually a few days)When the body is compromised, the white blood cells multiply to combat the invading agent or allergen, etc.Leukocytes can undergo diapedesisChemotaxis draws the leukocytes toward the invading agentFormed ElementsGranulocytesNeutrophils (normal range is 50–70 percent)Granules contain chemicals to kill bacteriaTypically the first WBC at the bacterial siteVery active phagocytic cellsNucleus is multilobedFormed ElementsGranulocytesEosinophils (normal range is 2–4 percent)Granules release chemicals that reduce inflammationAttack a foreign substance that has reacted with circulating antibodies (such as an allergic reaction or parasites)Typically have a bilobed nucleusFormed ElementsGranulocytesBasophils (normal range less than 1 percent)Granules release histamine and heparinHistamine dilates blood vesselsHeparin prevents abnormal blood clottingNucleus is usually hidden due to all the granulesFormed ElementsAgranulocytesMonocytes (normal range is 2–8 percent)Large phagocytic cellsNucleus is kidney-shaped or large oval-shapedRelease chemicals to attract other phagocytic cellsRelease chemicals to attract fibroblastsFibroblasts produce collagen fibers to surround an infected siteThese collagen fibers can produce scar tissueScar tissue forms a wall around the pathogen to prevent it from spreadingFormed ElementsAgranulocytesLymphocytes (normal range is 20–30 percent)Responsible for specific immunityCan differentiate to form:T cellsB cells NK cellsNucleus is typically large and round leaving a small halo around the entire nucleus or part of itFormed ElementsAgranulocytesT cellsAttack foreign cells directlyB cellsSecrete antibodies to attack foreign cellsNK cellsResponsible for immune surveillanceFormed ElementsPlateletsDerived from megakaryocytesMegakaryocytes will fragment forming bits and pieces of membrane-enclosed packets of chemicalsThe main chemical is platelet thromboplastin factorAbout 350,000 per microliter of bloodFormerly called thrombocytesFormed ElementsPlateletsThrombocytopeniaLower than normal number of plateletsThrombocytosisHigher than normal number of plateletsFormed ElementsPlatelet FunctionInvolved in blood clotting (hemostasis)Release chemicals to initiate the clotting process (platelet thromboplastin factor)Clump together to form a platelet plugContain actin and myosin that function to contract the clotHemopoiesisHemopoiesis (blood formation)Begins with pluripotential stem cellsDifferentiate to form two cells:Myeloid stem cells Lymphatic stem cellsHemopoiesisHemopoiesis Myeloid stem cells differentiate to eventually form:ErythrocytesPlateletsBasophilsEosinophilsNeutrophilsMonocytes HemopoiesisHemopoiesis (continued)Lymphatic stem cells differentiate to eventually form:LymphocytesHemopoiesisDetails of Hemopoiesis (blood formation)Begin with pluripotential stem cellsDifferentiate to form myeloid stem cellsDifferentiate to form progenitor cellsDifferentiate to form proerythroblast cellsDifferentiate to form erythroblast cellsDifferentiate to form reticulocytesDifferentiate to form erythrocytesHemopoiesisDetails of Hemopoiesis (continued)Begin with pluripotential stem cellsDifferentiate to form myeloid stem cellsDifferentiate to form progenitor cellsDifferentiate to form megakaryoblastsDifferentiate to form plateletsHemopoiesisDetails of Hemopoiesis (continued)Begin with pluripotential stem cellsDifferentiate to form myeloid stem cellsDifferentiate to form progenitor cellsDifferentiate to form myeloblasts and monoblastsMyeloblasts differentiate to form myelocytesMonoblasts differentiate to form promonocytesHemopoiesisDetails of Hemopoiesis (continued)Myelocytes differentiate to form band cells (nucleus forms a band)Band cells form segmented cells (nucleus becomes segmented)BasophilsEosinophilsNeutrophils Promonocytes differentiate to form monocytesHemopoiesisDetails of Hemopoiesis (continued)Begin with pluripotential stem cellsDifferentiate to form lymphatic stem cellsDifferentiate to form lymphoblastsDifferentiate to form prolymphocytesDifferentiate to form lymphocytesDifferentiate to form:B cellsT cellsNK cells ................
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