Chapter 18 - Blood - Textbook Notes PDF

Chapter 18 - Blood Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 1  18.1 Functions and General Composition of Blood Blood Continuously regenerated connective tissue Moves gases, nu...

Chapter 18 - Blood Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 1  18.1 Functions and General Composition of Blood Blood Continuously regenerated connective tissue Moves gases, nutrients, wastes, and hormones Transported through cardiovascular system Heart pumps blood Arteries transport blood away from heart Veins transport blood back to heart Capillaries allow exchange between blood and body tissues Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.1 Functions and General Composition of Blood 2 Blood components: formed elements and plasma Formed elements Erythrocytes (red blood cells) transport respiratory gases in the blood Leukocytes (white blood cells) defend against pathogens Platelets help form clots to prevent blood loss Plasma: fluid portion of blood Contains plasma proteins and dissolved solutes Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 3  Table 18.5 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.1a Functions of Blood 1 Transportation Transports formed elements, dissolved molecules and ions Carries oxygen from and carbon dioxide to the lungs Transports nutrients, hormones, heat and waste products Protection Leukocytes, plasma proteins, and other molecules (of immune system) protect against pathogens Platelets and certain plasma proteins protect against blood loss Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 5 18.1a Functions of Blood 2 Regulation of body conditions Body temperature Blood absorbs heat from body cells (especially muscle) Heat released at skin blood vessels Body pH Blood absorbs acid and base from body cells Blood contains chemical buffers Fluid balance Water is added to blood from GI tract Water lost through urine, skin, respiration Fluid is exchanged between blood and interstitial fluid Blood contains proteins and ions helping maintain osmotic balance Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 6 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  18.1c Components of Blood 1 Centrifuged blood Whole blood separated into parts by centrifuge Erythrocytes Bottom, red layer About 44% of sample Buffy coat Very thin (1%) middle layer with gray-white color Composed of leukocytes and platelets Plasma Straw-colored About 55% of sample Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 8 18.1c Components of Blood 2 Centrifuged blood Hematocrit Percentage of volume of all formed elements Clinical definition: percentage of only erythrocytes Adult males: 42 to 56%; females 38 to 46% Testosterone causes more erythropoietin secretion by kidney Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 9  Table 18.2 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Table 18.3 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Table 18.4 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Hemopoiesis Hemopoiesis: production of formed elements Occurs in red bone marrow of certain bones Hemocytoblasts: stem cells Myeloid line forms erythrocytes, all WBC’s except lymphocytes, and megakaryocytes Lymphoid line forms only lymphocytes Colony-stimulating factors (CSFs) stimulate hemopoiesis Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.3a Hematopoiesis 2 Erythropoiesis: red blood cell production Process requires iron, B vitamins, amino acids Begins with myeloid stem cell—responds to multi-CSF Forms progenitor cell Forms proerythroblast—a large nucleated cell Becomes erythroblast—smaller, produces hemoglobin Becomes normoblast—still smaller, more hemoglobin, anucleate Becomes reticulocyte—lacks organelles except ribosomes that make hemoglobin Becomes erythrocyte—ribosomes have degenerated Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 14 18.3a Hematopoiesis 3 Leukopoiesis: production of leukocytes Involves maturation of granulocytes, monocytes, lymphocytes Granulocytes are neutrophils, basophils, and eosinophils Multi-CSF and GM-CSF cause myeloid stem cell to form progenitor cell Progenitor cell becomes myeloblast that becomes a granulocyte Monocytes also derived from myeloid stem cells Stem cell differentiates into progenitor cell M-CSF prompts progenitor cell to become a monoblast Monoblast becomes a promonocyte, which matures into a monocyte Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 15 18.3a Hematopoiesis 4 Leukopoiesis (continued) Lymphocytes are derived from lymphoid stem cells Stem cells differentiate into B-lymphoblasts and T-lymphoblasts Lymphoblasts mature into B-lymphocytes and T-lymphocytes Some lymphoid stem cells differentiate directly into NK (natural killer) cells Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 16 18.3a Hematopoiesis 5 Thrombopoiesis: platelet production Megakaryoblast produced from myeloid stem cell Forms megakaryocyte under influence of thrombopoietin Large size and multilobed nucleus Megakaryocyte produces thousands of platelets Large cell produces proplatelets—long extensions These extend through blood vessel wall into bloodstream Blood flow “slices” off fragments which are platelets Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 17 18.3b Erythrocytes Erythrocytes (red blood cells) Small, flexible formed elements Lack nucleus and cellular organelles; packed with hemoglobin Have biconcave disc structure Has latticework of spectrin protein providing support and flexibility Transport oxygen and carbon dioxide between tissues and lungs Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Hemoglobin Hemoglobin: red-pigmented protein Oxygen binds to iron Transports O2 and CO2 Binding is fairly weak Oxygenated when loaded with Rapid attachment in lungs O2 and rapid detachment in Deoxygenated when some O2 body tissues lost Carbon dioxide binds to Each Hgb molecule is globin protein (not iron) composed of 4 globins 2 -alpha chains and 2- beta Binding is fairly weak chains Attachment in body tissue Each chain has a heme group: Oxygen binds to the iron ion, so each and detachment in lungs hemoglobin can bind 4 O2 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 19  Molecular Structure of Hemoglobin Figure 18.6 Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 20  How Erythropoietin (EPO) Regulates Erythrocyte Production Figure 18.7 Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 21 Clinical View: Blood Doping Used by some athletes to enhance performance One method, self donation of erythrocytes Blood removal prior to competition increases EPO production Erythrocytes transfused back prior to competition Second method: pharmaceutical EPO Dangers Increased blood viscosity Heart required to work harder May cause permanent cardiovascular damage Banned from athletic competition Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 22  Figure 18.8 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. Clinical View: Anemia Either the percentage of erythrocytes is lower than normal or the oxygen-carrying capacity is reduced Symptoms: lethargy, shortness of breath, pallor, palpitations Types: Aplastic anemia – defective red marrow due to poisons, toxins, radiation Congenital hemolytic anemia – genetic defect; erythrocytes destroyed Erythroblastic anemia (beta thalassemia) – large numbers of immature cells due to abnormal accelerated cell maturation Hemorrhagic anemia – due to blood loss Pernicious anemia – failure to absorb vitamin B12 due to lack of intrinsic factor Sickle-cell disease – genetic defect; abnormal hemoglobin Some cases can be treated by pharmaceutical EPO Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 24  Figure 18.9a Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  Rh Blood Types Presence or absence of Rh factor (surface antigen D) on erythrocytes determines if blood type is positive or negative Antibodies to Rh factor (anti-D antibodies) not usually there Only appear after Rh negative person exposed to Rh positive blood ABO group and Rh type are reported together For example if all 3 antigens are present, blood type is described as AB+ Figure 18.9b Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 26  18.3b Erythrocytes 9 Clinical considerations about blood types If someone receives an incompatible transfusion agglutination occurs Recipient’s antibodies bind to transfused erythrocytes and clump them together Can block blood vessels and prevent normal circulation Can cause hemolysis, rupture of erythrocytes, organ damage Figure 18.9c Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 27  Erythrocyte Agglutination Figure 18.10a Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 28  Agglutination Test Figure 18.10b Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the (b)prior (Top,written Bottom)consent of McGraw Hill ISM/Jean-Claude LLC. RÉVY/Medical Images 29 Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.3c Leukocytes 1 Leukocyte characteristics Defend against pathogens Contain nucleus and organelles, but not hemoglobin Motile and flexible—most not in blood but in tissues Diapedesis: process of squeezing through blood vessel wall Chemotaxis: attraction of leukocytes to chemicals at an infection site Five leukocyte types divided into two classes Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 31  Leukocytes (photos): (Lymphocyte), (Neutrophil), (Eosinophil) and (Basophil) Alvin Telser/McGraw-Hill Education; (Monocyte) ISM/Herve CONGE/Medical Imagesages Image of Table 18.7, top Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 32 18.3c Leukocytes Five leukocyte types divided into two distinguishable classes based on visible presence of secretory vesicles (specific granules): Granulocytes have visible granules seen with light microscope Neutrophils, eosinophils, basophils Agranulocytes have smaller granules that are not visible with light microscope Lymphocytes, monocytes Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 33 18.3c Leukocytes Granulocytes Neutrophils (polymorphonuclear leukocytes) Most numerous leukocyte in blood Multilobed nucleus Cytoplasm has pale granules when stained Enter tissue spaces and phagocytize infectious pathogens Numbers rise dramatically in chronic bacterial infection Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 34 18.3c Leukocytes Eosinophils 1–4% of leukocytes Bilobed nucleus connected by thin strand Cytoplasm has reddish granules Phagocytize antigen-antibody complexes or allergens Active in cases of parasitic worm infection Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 35 18.3c Leukocytes Basophils 0.5–1% of leukocytes Bilobed nucleus Cytoplasm has blue-violet granules with histamine and heparin Histamine release causes increase in blood vessel diameter and capillary permeability (classic allergy symptoms) Heparin release inhibits blood clotting Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 36 18.3c Leukocytes Agranulocytes Monocytes C-shaped nucleus 2–8% of blood leukocytes Take up residence in tissues Transform into large phagocytic cells, macrophages Phagocytize bacteria, viruses, debris Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 37 18.3c Leukocytes 7 Lymphocytes Reside in lymphoid organs and structures 20–40% of blood leukocytes Dark-staining round nucleus Three categories T-lymphocytes manage immune response B-lymphocytes become plasma cells and produce antibodies NK (natural killer) cells attack abnormal and infected tissue cells Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 38 18.3c Leukocytes 8 Differential count and changes in leukocyte profiles Leukopenia: reduced number of leukocytes Increases risk of infection Leukocytosis: elevated leukocyte count May be caused by recent infection or stress Differential count: measures amount of each type of leukocyte and whether any are immature Useful for clinical diagnoses Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 39 Clinical View: Leukemia Malignancy in leukocyte-forming cells Abnormal development and proliferation of leukocytes Increase in abnormal leukocyte number Decrease in erythrocyte and megakaryocytic lines Results in anemia and bleeding Acute leukemia Rapid progression Death typically within months in children and young adults Chronic leukemia Slower progression In middle-aged and older individuals Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 40 18.3d Platelets Platelets Small, membrane-enclosed cell fragments No nucleus Break off of megakaryocytes in red marrow Important role in blood clotting Normally 150,000 to 400,000 per cubic millimeter blood 30% stored in spleen Circulate for 8 to 10 days; then broken down and recycled Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 41  Hemostasis Hemostasis: stoppage of bleeding Three overlapping phases: Figure 18.12 Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 42 18.4a Vascular Spasm Vascular spasm: blood vessel constriction First phase in response to blood vessel injury Limits blood leakage Lasts from few to many minutes Platelets and endothelial cells release chemicals that stimulate further constriction Greater vasoconstriction with greater vessel damage Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 43 18.4b Platelet Plug Formation 1 Normally (when uninjured) platelet activation is inhibited Vessel’s endothelial wall smooth and coated with prostacyclin Prostacyclin is an eicosanoid that repels platelets It causes endothelial cells and platelets to make cAMP which inhibits platelet activation When blood vessel damaged, a platelet plug is formed Collagen fibers in vessel wall exposed Platelets stick to collagen with help of von Willebrand factor Platelets develop long processes allowing for better adhesion Many platelets aggregate and close off injury Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 44 18.4b Platelet Plug Formation 2 Platelet activation Platelets’ cytosol degranulates and releases chemicals Serotonin and thromboxane A2 cause prolonged vascular spasms Adenosine diphosphate (ADP) and thromboxane A2 attract other platelets and facilitate their degranulation (positive feedback) Procoagulants stimulate coagulation Mitosis stimulating substances trigger repair of blood vessel Thrombocytopenia (low platelet count) impairs all phases of hemostasis Platelet plug forms quickly (1 min) but is prevented from getting too large by prostacyclin secretion by nearby, healthy cells Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 45  18.4c Coagulation Phase 1 Coagulation: blood clotting Network of fibrin (insoluble protein) forms a mesh Fibrin comes from soluble precursor fibrinogen Mesh traps erythrocytes, leukocytes, platelets, plasma proteins to form clot (b) Courtesy of John Weisel Figure 18.11 Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 46 18.4c Coagulation Phase 2 Substances involved in coagulation Clotting requires calcium, clotting factors, platelets, vitamin K Clotting factors—most are inactive enzymes Named in order of their discovery Factor 1= fibrinogen; factor 2 = prothrombin etc. Most are produced in the liver Vitamin K A fat-soluble coenzyme required for synthesis of clotting factors 2, 7, 9, and 10 Some factors (for example, factor 7) are proteases that cleave other factors from inactive to active forms Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 47  18.4c Coagulation Phase 3 Initiation of coagulation cascade Clotting starts with the intrinsic and extrinsic pathways Intrinsic pathway Initiated by platelets upon damage to inside of vessel wall Five steps that are complete in 3 to 6 minutes: Extrinsic pathway Initiated by damage outside of vessel Two steps take about 15 seconds Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 18.4c Coagulation Phase 5 Initiation of coagulation cascade (continued) Common pathway Activated by extrinsic or intrinsic pathway Four steps 1) Factor 10 combines with factors 2 and 5, Ca2+ , and platelet factor 3 to form prothrombin activator. 2) Prothrombin activator activates prothrombin to thrombin. 3) Thrombin converts soluble fibrinogen to soluble fibrin. 4) Factor 13 is activated in presence of Ca2+. Factor 13 cross-links fibrin monomers into a fibrin polymer. Positive feedback leads to clot formation Clot stops once fibrin fills mesh Extra fibrin is destroyed by enzymes in the blood Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 49  Coagulation Pathways Figure 18.13 Access the text alternative for slide images. Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 50 18.4c Coagulation Phase 6 The sympathetic response to blood loss If greater than 10% of blood lost Sympathetic nervous system increases vasoconstriction, heart rate, force of heart contraction Blood redistributed to heart and brain Effective in maintaining blood pressure until 40% of blood lost Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 51 18.4d Elimination of the Clot 1 Clot elimination includes clot retraction and fibrinolysis Clot retraction Actinomyosin (protein within platelets) contracts and squeezes serum out of developing clot making it smaller Fibrinolysis Degradation of fibrin strands by plasmin Begins within 2 days after clot formation Occurs slowly over a number of days Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 52 18.4d Elimination of the Clot 2 Blood balances clot elimination and clot formation Imbalances can lead to bleeding or blood clotting disorders Damaged vessels, impaired blood flow, atherosclerosis or vessel inflammation tip the balance toward clotting Certain nutrients, ions, vitamins must be present for clot to form correctly Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 53 Clinical View: Bleeding and Blood Clotting Disorders 1 Hemophilia: bleeding disorders Hemophilia A and hemophilia B most common Occur in X-linked recessive pattern Males exhibit full-blown disease; females typically carriers Result from deficiency of factor VIII, factor IX, or factor XI (more rare) Thrombocytopenia: platelet deficiency Increased breakdown or decreased production May occur in bone marrow infections or cancer Certain drugs interfere with clotting (can cause bleeding) For example, aspirin, ibuprofen, warfarin, ginkgo Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 54 Clinical View: Bleeding and Blood Clotting Disorders 2 Hypercoagulation Increased tendency to clot blood Can lead to thrombus, blood vessel clot When dislodged within blood, embolus If lodges in lungs, pulmonary embolism Can cause breathing problems and death Can have drug-related, environmental, and genetic causes For example, birth control pills, prolonged inactivity Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 55 18.5 Development and Aging of Blood Hematopoiesis Occurs in most bones in young children Restricted to selected bones in axial skeleton in adulthood Older red bone marrow replaced with fat as individuals age Older individuals more likely to become anemic May produce fewer and less active leukocytes Certain types of leukemia more prevalent in elderly Copyright 2022 © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC. 56