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The Blood

The Blood . Functions of Blood. Transportation O 2 , nutrients, waste, hormones, heat Regulation—maintain homeostasis of body fluids Regulate pH, body temperature, maintain fluid volume Protection Clotting prevents loss of fluids White blood cells protect against disease

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The Blood

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  1. The Blood

  2. Functions of Blood • Transportation • O2, nutrients, waste, hormones, heat • Regulation—maintain homeostasis of body fluids • Regulate pH, body temperature, maintain fluid volume • Protection • Clotting prevents loss of fluids • White blood cells protect against disease • Blood proteins protect against disease

  3. Physical characteristics and volume • Salty and metallic tasting • More dense than water • Slightly alkaline, pH between 7.35 and 7.45 • Temperature ~ 38o C or 100.4o F • Makes up 8% of body weight • Volume in adult males is 5-6 L and in females 4-5 L • Only fluid tissue in the body

  4. Blood components • Blood plasma 55% • Formed elements 45% • RBCs—measurement is hematocrit 14% + 5% • Leukocytes and platelets

  5. Blood plasma • Includes over 100 different dissolved solutes

  6. Formed Elements

  7. Hematopoiesis • Occurs in the red bone marrow from hemocytoblast/ hematopoietic stem cell • Specialization based on receptors that respond to …hormones

  8. Erythrocyte structure • Flexible structure, large surface area • Lack a nucleus and other organelles. • 33% of weight is hemoglobin molecules. • Other proteins include antioxidants and those to maintain RBC shape (spectrin)

  9. Erythrocyte function • Dedicated to carry respiratory gas

  10. Regulation of RBCs Erythropoietin (EOP) glycoprotein hormone produced by kidneys to liver

  11. Dietary needs to produce RBCs • Iron, AAs, lipids, and carbohydrates. • Iron is absorbed from the diet • 65% found in hemoglobin • The rest stored in liver, spleen and bone marrow • Iron is toxic and requires transferrin as a transporter • Some iron is lost in feces and menstrual blood • Vitamin B12 and folic acid are necessary for DNA synthesis

  12. Fate and death of RBCs • RBCs have a lifespan of 100 to 120 days • Age makes them less flexible and the hemoglobin begins to degenerate. • Old RBCs get trapped in the small capillaries of the spleen • Macrophages destroy and digest RBCs • Heme and globin are separated • Globin broken down into a.a.s Heme bilirubinurobilinogenstercobilin Bloodliverintestineanus

  13. Erythrocyte Imbalances • Anemia  reduced O2 carrying capacity of the blood • Insufficient number of RBCs: • Hemorrhagic - due to blood loss associated with an injury, undiagnosed bleeding ulcer, etc. • Hemolytic - due to blood loss due to transfusion reactions & certain bacterial and parasite infections • Aplastic - due to destruction or inhibition of red marrow by drugs, ionizing radiation or certain bacterial toxins.

  14. Erythrocyte Imbalances • Anemia  reduced O2 carrying capacity of the blood • Low hemoglobin content: • Iron Deficiency - inadequate intake or absorption of iron, forms microcytes. • Pernicious - dietary deficiency of Vitamin B12 or inadequate production of intrinsic factor for absorption of Vitamin B12 , forms macrocytes

  15. Erythrocyte Imbalances • Anemia  reduced O2 carrying capacity of the blood • Abnormal Hemoglobin in RBCs • Thalassemias- one globin chain is absent/faulty • Polycythemia-excess of erythrocytes increasing blood viscosity

  16. Erythrocyte Imbalances • Polycythemia - abnormally high number of RBCs (8 - 11 million/mm3). Increases blood viscosity & blood pressure. • most often the result of bone marrow cancer. • Lecuopenia - abnormally low number of WBCs (less than 5,000/mm3). • drugs, steroids & anti-cancer agents.

  17. Leukocytes Structure • WBCs have a nucleus and other organelles. • WBCs can undergo diapedesis using amoeboid motion when in the tissues • Use chemical chemotaxis to follow trail to infection or damaged tissue.

  18. Granular leukocytes • Neutrophils • multilobed nucleus, inconspicuous granules • Phagocytize bacteria & some fungi • Produced in bone marrow by myeloblasts • Eosinophils • bilobed nucleus, red granules • Destroy parasitic worms & immune complexes • Produced in bone marrow by myeloblasts • Basophils • lobed nucleus, purple-black granules • Cause vasodilation by release of histamines • Produced in bone marrow by myeloblasts

  19. Agranular leukocytes • Lymphocyte • B lymphocytes - Humoral Immunity (antibodies) • T lymphocytes - Cellular Immunity • Produced in lymphatic tissues • Monocytes • Differentiate into macrophages in tissues. • Provide defense against viruses & intracellular bacteria in chronic infections. • Produced by monoblasts in lymphatic tissues.

  20. Production of leukocytes • Leukopoiesis is stimulated by interleukins and colony-stimulating factors (CSFs) • Pluripotent stem cells have the capacity to differentiate into several types of cells. • Myeloid stem cells • Lymphoid stem cell

  21. Leukocyte Imbalances • Leukopenia—low WBC count • Leukemia—unchecked growth of a single unspecialized clone. Abnormally high numbers of immature WBCs that are mitotic & unspecialized • Acute leukemia occurs if it derives from blast-type cells • Chronic leukemia occurs if it derives from later stages • Bone marrow is compromised and defense system becomes nonfunctional • Infectious mononucleosis derives from excessive numbers of agranulocytes (Epstein-Barr virus)

  22. Platelets • Under the influence of thrombopoietin, myeloid stem cells develop into megakaryocytes (huge cells). • These cells fragment into 2-3K particles. • They have a very short life of 5- 9 days.

  23. Hemostasis • Damaged blood vessels require a rapid, localized and controlled hemostatic response to reduce blood loss. • Vascular spasm/constriction • Platelet plug formation • Blood clotting/ coagulation

  24. Platelet plug formation: platelet adhesion

  25. Platelet plug formation: platelet release action

  26. Platelet plug formation: platelet aggregation

  27. Stages of clotting • Extrinsic (s) and intrinsic (min) pthwys make prothrombinase. • Prothrombinase & Ca2+ Catalyze prothrombin  thrombin • Thrombin & Ca2+ converts soluble fibrinogen insoluble fibrin (thread of the clot) • Thrombin activates factor XIII which stabilizes & strengthens threads

  28. Hemostasis Animation

  29. Thromboemolitic Disorders • Thrombus clot in an unbroken vessel • Ebolus an abnormal object moving through a blood vessel, Clot, air bubble, lipid droplet, thrombus, etc. • Disorders • Embolisms (pulmonary, cerebral, cardiac) • Artherosclerosis • Inflammation • Treatment • Aspirin • Heparin • Warfarin

  30. Bleeding disorders • Thrombocytopenia—low platelet levels • Impaired liver function • Vitamin K • Hemophilia • Deficiency of factor VIII (antihemophilic factor) • Deficiency of factor IX • Lack of factor XI

  31. ABO blood typing • Based on two glycolipid antigens, A and B. • Blood has agglutinogens (antibodies) that react to A or B antigens.

  32. Blood groups and blood types

  33. Rh blood groups Hemolytic disease of newborn (HDN)

  34. Transfusion reactions • Agglutination clogs blood capillaries • Clumped cells will rupture and be phagocytized by macrophages • Hemoglobin is released into the blood • Oxygen carrying is disrupted • Blood flow is impaired • Hemoglobin passing into kidney tubules causes cell death and renal shutdown

  35. Diagnostic blood tests • Lipidemia is characteristic of those with heart disease • Erythrocyte morphology can detect anemias • Differential white blood cell count • High eosinophil indicates allergies or parasitic infection • Platelet count (thrombocytopenia) • SMAC is blood chemistry profile • CBC provides information on the formed elements

  36. Resources • Heart Anatomy Tutorial: • Hematopoiesis Overview: • BodySmart Blood & Bloodcells

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