Ch19 Blood Sum 09
- 1. Ch. 19 Blood The Cardiovascular System A circulating transport system: a pump (the heart) a conducting system (blood vessels) a fluid medium (blood) Functions of the Cardiovascular System To transport materials to and from cells: oxygen and carbon dioxide nutrients hormones immune system components waste products
- 2. Blood Is specialized fluid of connective tissue Contains cells suspended in a fluid matrix 5 Functions of Blood Transport of dissolved substances Gases-O2 from lungs to tissues Nutrients-from digestive tract, storage, or liver Hormones-such as from endocrine glands to target cells Waste products-from cells to kidneys Regulation of pH and ions
- 3. Regulation of pH and ions Ions – either add or subtract i.e. Ca or K by diffusion w/ interstitial fluid & blood Absorbs & neutralize acid - i.e lactic acid from skeletal muscles Restriction of fluid losses at injury sites - Clotting Defense against toxins and pathogens - WBC – transported by blood to fight infection & remove debris Stabilization of body temperature - Heat loss via skin if hot - Heat retention to brain and other vital organs via shunting
- 4. Whole Blood Plasma : Fluid proteins in solution Like interstitial fluid Formed elements : all cells and cell fragments Plasma Water Dissolved plasma proteins Other solutes similar to, & exchanges fluids with, interstitial fluid Is matrix of formed elements
- 5. 3 Types of Formed Elements Red blood cells ( RBCs ) or erythrocytes : transport oxygen White blood cells ( WBCs ) or leukocytes : part of the immune system Platelets : cell fragments involved in clotting Hemopoiesis Process of producing formed elements By myeloid and lymphoid stem cells Fractionation Process of separating whole blood for clinical analysis: into plasma and formed elements
- 6. 3 General Characteristics of Blood 38°C (100.4°F) is normal temperature High viscosity Slightly alkaline pH (7.35–7.45) Blood Volume Blood volume (liters) = 7% of body weight (kilograms): adult male: 5 to 6 liters adult female: 4 to 5 liters
- 7. Plasma Makes up 50–60% of blood volume More than 90% of plasma is water Figure 19–1b
- 8. Extracellular Fluids Interstitial fluid (IF) and plasma Materials plasma and IF exchange across capillary walls: water ions small solutes Differences between Plasma and IF Levels of O 2 and CO 2 Dissolved proteins: plasma proteins do not pass through capillary walls
- 9. 3 Classes of Plasma Proteins Albumins (60%) Globulins (35%) Fibrinogen (4%) Albumins Transport substances: fatty acids thyroid hormones steroid hormones Fibrinogen Molecules form clots Produce long, insoluble strands of fibrin If remove clotting proteins, = serum
- 10. Globulins Antibodies , also called immunoglobulins - Attack foreign bodies Transport globulins (small molecules): hormone-binding proteins – thyroid binding protein binds thyroid hormones; transcortin binds acth (adrenocorticoytropic hormone), stimulates thyroid Metalloproteins- i.e. transferrin for Fe apolipoproteins ( lipoproteins ) steroid-binding proteins – i.e. testosterone binding hormone binds & transports testosterone
- 11. Serum Liquid part of a blood sample in which dissolved fibrinogen has converted to solid fibrin Other Plasma Proteins 1% of plasma: changing quantities of specialized plasma proteins enzymes, hormones, and prohormones TSH, FSH, LH, insulin, prolactin Origins of Plasma Proteins 90% made in liver All albumin and fibrinogen Antibodies made by plasma cells made by lymphocytes Peptide hormones made by endocrine organs
- 12. Red Blood Cells Red blood cells (RBCs) make up 99.9% of blood’s formed elements Measuring RBCs Red blood cell count: reports # of RBCs in 1 microliter whole blood Hematocrit (packed cell volume, PCV): percentage of RBCs in centrifuged whole blood Normal Blood Counts RBC : male: 4.5–6.3 million, female: 4.–5.5 million Hematocrit : male: 40–54%, female: 37–47% Why different? Males have androgens that stimulate RBC production
- 13. RBC Structure Small and highly specialized disc Thin in middle and thicker at edge Figure 19–2d Importance of RBC - Shape and Size High surface-to-volume ratio: quickly absorbs and releases oxygen Discs form stacks: smoothes flow through narrow blood vessels Discs bend and flex entering small capillaries: 7.8 µ m RBC passes through 4 µ m capillary
- 14. Lifespan of RBCs Lack nuclei, mitochondria, and ribosomes Live about 120 days Hemoglobin (Hb) Protein molecule, transports respiratory gases Responsible for cells ability to transport O2 and CO2 Normal hemoglobin: 14–18 g/dl whole blood - males 12-16 g/dl “” - females
- 15. Hemoglobin Structure Complex quaternary structure Figure 19–3 4 globular protein subunits: each with 1 molecule of heme each heme contains 1 iron ion Iron ions easily: associate with oxygen ( oxyhemoglobin ) or dissociate from oxygen ( deoxyhemoglobin )
- 16. Fetal Hemoglobin Strong form of hemoglobin found in embryo/fetus Takes oxygen from mother’s hemoglobin at the placenta begins last 7 months in utero and continues over the first year FH can be stimulated in adults with SCA or thalassemia – only adult from of hemaglobin is abnormal Hemoglobin Function Each RBC has 280 million Hb molecules Each Hb molecule has 4 heme units So each RBC potentially has more 1 billion O 2 molecules
- 17. Carbaminohemoglobin With low oxygen (peripheral capillaries): hemoglobin releases oxygen which makes plasma CO2 elevated Alpha and beta chains binds carbon dioxide and carries it to lungs Carbaminohemoglobin is formed RBC then absorb O2 and releases CO2 Anemia Hematocrit or hemoglobin levels are below normal Is caused by several conditions
- 18. Recycling RBCs 1% of circulating RBCs wear out per day: about 3 million RBCs per second Macrophages of liver, spleen, and bone marrow: monitor RBCs engulf RBCs before membranes rupture (hemolyze) Figure 19–4
- 19. Diagnosing Disorders Hemoglobinuria : hemoglobin breakdown products in urine due to excess hemolysis in blood stream Hematuria : whole red blood cells in urine due to kidney or tissue damage Hemoglobin Recycling Phagocytes break hemoglobin into components: globular proteins to amino acids heme to biliverdin iron
- 20. Iron Recycling To transport proteins ( transferrin ) To storage proteins ( feritin and hemosiderin ) Breakdown of Biliverdin Biliverdin (green) is converted to bilirubin (yellow) Bilirubin is: excreted by liver (bile) jaundice is caused by bilirubin buildup converted by intestinal bacteria to urobilins and stercobilins
- 21. RBC Maturation Red blood cell formation Occurs only in red bone marrow (myeloid tissue) Stem cells mature to become RBCs Figure 19–5 Erythropoiesis Hemocytoblasts Stem cells in bone marrow divide to produce: myeloid stem cells : become RBCs, some WBCs lymphoid stem cells : become lymphocytes
- 22. Stages of RBC Maturation Myeloid stem cell Proerythroblast Erythroblasts Reticulocyte Mature RBC Components Building red blood cells requires: amino acids iron vitamins B 12 , B 6 , and folic acid
- 23. Pernicious Anemia Low RBC production Due to unavailability of vitamin B 12 Stimulating Hormones Erythropoietin (EPO) Also called erythropoiesis-stimulating hormone: secreted when oxygen in peripheral tissues is low ( hypoxia ) due to disease or high altitude
- 24. RBC Tests Table 19–1
- 25. Surface Antigens Are cell surface proteins that identify cells to immune system Triggers immune response Normal cells are ignored and foreign cells attacked Each cell has surface AG (antigens) Allows for recognition of self Blood Types Are genetically determined By presence or absence of RBC surface antigens A , B , Rh
- 26. 4 Basic Blood Types A (surface antigen A) B (surface antigen B) AB (antigens A and B) O (neither A nor B) Figure 19–6a
- 27. Agglutinogens Antigens on surface of RBCs Screened by immune system Plasma antibodies attack ( agglutinate ) foreign antigens Blood Plasma Antibodies Type A: type B antibodies Type B: type A antibodies Type O: both A and B antibodies Type AB: neither A nor B
- 28. The Rh Factor Also called D antigen Either Rh positive (Rh + ) or Rh negative (Rh — ) Only sensitized Rh — blood has anti-Rh antibodies So . . . Rh+ mom has Rh- baby - no problems ever Rh- mom + Rh+ dad = Rh+ baby – no problem for pregnancy Blood will mix around delivery & mom will make anti-Rh AB Second baby that is Rh+ will be attacked by mom’s anti-Rh AB can cause death at or before delivery Known as Hemolytic Disease of the Newborn or erythroblastalis fetalis Newborn born with this is anemic and jaundiced May have to have complete transfusion RhoGam – to mom prevents production of anti-Rh AB last 3 months of pregnancy and before and after delivery
- 29. Cross-Reaction Also called transfusion reaction Plasma antibody meets its specific surface antigen Blood will agglutinate and hemolyze If donor and recipient blood types not compatible Figure 19–6b
- 30. White Blood Cells ( WBCs ) Also called leukocytes Do not have hemoglobin Have nuclei and other organelles WBC Functions Defend against pathogens Remove toxins and wastes Attack abnormal cells WBC Movement Most WBCs in connective tissue proper & lymphatic system organs Small numbers in blood: 6000 to 9000 per microliter
- 31. Circulating WBCs Migrate out of bloodstream - Margination-activated WBCs adhere to vessel walls, then can squeeze thru (emigration or diapedesis) Have amoeboid movement - Gliding movement, needs ATP and Ca - Movement of emigration Attracted to chemical stimuli ( positive chemotaxis ) - Chemicals guide WBC to invading pathogens, damaged tissues, and other WBC Some are phagocytic: neutrophils, eosinophils (microphages), and monocytes (macrophage) Engulf waste and pathogens
- 32. Types of WBCs Neutrophils Eosinophils Basophils Monocytes Lymphocytes Figure 19–9
- 33. Neutrophils Also called polymorphonuclear leukocytes 50–70% of circulating WBCs 12 um in dia 10 hour life span - eats 12-24 bacteria first Very dense 2-5 segment nucleus Pale cytoplasm granules with lysosomal enzymes & bactericides (hydrogen peroxide and superoxide) Neutrophil Action Very active, first to attack bacteria, fungi, and some viruses Engulf pathogens Digest pathogens Release prostaglandins (hormones) and leukotrienes (calls other cells). Contributes to local inflammation Form pus (dead neutrophils, cell debris and waste)
- 34. Eosinophils Also called acidophils 2–4% of circulating WBCs 12 um dia 2 lobed nucleus Attack large parasites, then toxic compounds: nitric oxide & cytotoxic enzymes Eosinophil Actions Are sensitive to allergens Control inflammation with enzymes that counteract inflammatory effects of neutrophils and mast cells
- 35. Basophils Are less than 1% of circulating WBCs Are small - <8-10 um diameter Migrate to site via capallaries Accumulate in damaged tissue Basophil Actions Release chemicals that attract basophils and eosinophils Granuales discharged into interstitial fluid. They contain: histamine : dilates blood vessels heparin : prevents blood clotting Both enhance inflammation
- 36. Monocytes += 15 um diam 2–8% of circulating WBCs Are large and spherical Large or kidney nucleus Enter peripheral tissues and become macrophages after 24 hours – aggressive Macrophage Actions Engulf large particles and pathogens Secrete substances that attract immune system cells and fibroblasts to injured area
- 37. Lymphocytes 20–30% of circulating WBCs Very small, but larger than RBCs Large round nucleus w/ thin cytopalmic halo Migrate in and out of blood Mostly in connective tissues & lymphatic organs Lymphocyte Actions Are part of the body’s specific defense system 3 classes T cells B cells Natural killer (NK) cells
- 38. T cells Cell-mediated immunity Attack foreign cells directly Coordinates immune response B cells Humoral immunity Produce and distribute AB Differentiate into plasma cells Synthesize and distribute antibodies Natural Killer Cells (NK) Immune survelliance Detect and destroy abnormal tissue cells (cancers)
- 39. WBC Disorders Leukopenia : abnormally low WBC count Leukocytosis : abnormally high WBC count Leukemia : extremely high WBC count WBC Production All blood cells originate from hemocytoblasts: which produce myeloid stem cells and lymphoid stem cells
- 40. Myeloid Stem Cells Differentiate into progenitor cells : which produce all WBCs except lymphocytes Lymphocytes Are produced by lymphoid stem cells Lymphopoiesis : the production of lymphocytes WBC Development WBCs, except monocytes: develop fully in bone marrow Monocytes: develop into macrophages in peripheral tissues
- 41. Other Lymphopoiesis Some lymphoid stem cells migrate to peripheral lymphoid tissues (thymus, spleen, lymph nodes) Also produce lymphocytes
- 42. Summary: Formed Elements of Blood Table 19–3
- 43. Platelets Cell fragments involved in human clotting system - 4um dia and 1 um thick – “sticky” Nonmammalian vertebrates have t hrombocytes (nucleated cells) Platelet Circulation Circulates for 9–12 days Dead removed by phagocytosis in spleen 2/3 are reserved for emergencies Platelet Counts 150,000 to 500,000 per microliter Thrombocytopenia : abnormally low platelet count Thrombocytosis : abnormally high platelet count
- 44. 3 Functions of Platelets Release important clotting chemicals Temporarily patch damaged vessel walls Actively contract tissue after clot formation Platelet Production Also called thrombocytopoiesis : occurs in bone marrow Megakaryocytes Giant cells Manufacture platelets from cytoplasm Each cell produces ~4000 platelets
- 45. Hemostasis The cessation of bleeding: vascular phase platelet phase coagulation phase
- 46. Endothelial cells contract Contraction is due to 1. Endothelial cells and platelets releasing chemicals 2. pain receptors initiate reflexes stimulate smooth muscle contraction Endothelial cell membranes become “sticky”: - seal off blood flow Von Willebrand factor (large plasma protein) synthesized by endothelial cells causes the stickiness by binding to proteins and cells The Vascular Phase A cut triggers immediate response = vascular spasm 20 to 30-minute contraction
- 47. The Platelet Phase Begins within 15 seconds after injury Figure 19–11b Platelet adhesion (attachment): to sticky endothelial surfaces to basal laminae to exposed collagen fibers Platelet aggregation (stick together): forms platelet plug which closes small breaks
- 48. Activated Platelets Release Clotting Compounds Granules in Platelets break down and release Adenosine diphosphate (ADP) – aggregating agent (more platelets) Thromboxane A 2 and serotonin – enhance vascular spasm
- 49. This is a positive feedback cycle that activates and attracts more and more platelets to the area. Within 1 minute a platelet plug is built Platelet Plug: Size Restriction Prostacyclin : released by endothelial cells inhibits platelet aggregation Inhibitory compounds: released by other white blood cells
- 50. The Coagulation Phase Begins 30 seconds or more after the injury Figure 19–12a Blood clotting ( coagulation ): Involves a series of steps converts circulating fibrinogen into insoluble fibrin Blood Clot Fibrin network Covers platelet plug Traps blood cells Seals off area Clotting factors Also called procoagulants Proteins or ions in plasma Required for normal clotting
- 51. Cascade Reactions During coagulation phase Chain reactions of enzymes and proenzymes Form 3 pathways 3 Coagulation Pathways Extrinsic pathway : begins in the vessel wall outside blood stream Intrinsic pathway : begins with circulating proenzymes within bloodstream Common pathway: where intrinsic and extrinsic pathways converge
- 52. 3 Coagulation Pathways The Extrinsic Pathway Damaged cells release tissue factor (TF) TF + other compounds = enzyme complex Activates Factor X The Intrinsic Pathway Activation of enzymes by collagen Platelets release factors ( e.g., PF–3 ) Series of reactions activate Factor X
- 53. The Common Pathway Enzymes activate Factor X Forms enzyme prothrombinase Converts prothrombin to thrombin Thrombin converts fibrinogen to fibrin Thrombin stimulates formation of tissue factor stimulates release of PF-3: forms positive feedback loop (intrinsic and extrinsic): accelerates clotting Clotting: Area Restriction Anticoagulants (plasma proteins): antithrombin-III & alpha-2-macroglobulin Heparin Protein C (activated by thrombomodulin ) Prostacyclin
- 54. Other Factors Calcium ions (Ca 2+ ) and vitamin K are both essential to the clotting process Clot Retraction After clot has formed: Platelets contract and pull torn area together Takes 30–60 minutes Fibrinolysis Slow process of dissolving clot: thrombin and tissue plasminogen activator (t-PA) : activate plasminogen Plasminogen produces plasmin : digests fibrin strands
- 55. Disorders of Hemostasis Thrombembolic disorders – clots too easily Thrombus – clot that develops and persists in an unbroken blood vessel (may prevent blood flow and cause tissue death) - Coronary thrombosis Embolus – thrombus that breaks away from the vessel wall and travels through bloodstream Embolism – obstructs a vessel (pulmonary embolism) Bedridden patients, long flights (slow moving blood) Bleeding Disorders – prevent normal clotting Thrombocytopenia – platelet numbers low Impaired liver function – not able to synthesize coagulants Hemophilias – several hereditary conditions (person doesn’t make the clotting factors correctly