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Blood

Blood. Blood. The only fluid tissue in the human body Classified as a connective tissue Components of blood Living cells Formed elements Non-living matrix Plasma. Blood. If blood is centrifuged Erythrocytes sink to the bottom (45% of blood, a percentage known as the hematocrit)

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Blood

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  1. Blood

  2. Blood • The only fluid tissue in the human body • Classified as a connective tissue • Components of blood • Living cells • Formed elements • Non-living matrix • Plasma

  3. Blood • If blood is centrifuged • Erythrocytes sink to the bottom (45% of blood, a percentage known as the hematocrit) • Buffy coat contains leukocytes and platelets (less than 1% of blood) • Buffy coat is a thin, whitish layer between the erythrocytes and plasma • Plasma rises to the top (55% of blood)

  4. Blood Figure 10.1 (1 of 2)

  5. Blood Figure 10.1 (2 of 2)

  6. Physical Characteristics of Blood • Color range • Oxygen-rich blood is scarlet red • Oxygen-poor blood is dull red • pH must remain between 7.35–7.45 • Blood temperature is slightly higher than body temperature at 100.4°F • In a healthy man, blood volume is about 5–6 liters or about 6 quarts • Blood makes up 8% of body weight

  7. Blood Plasma • Composed of approximately 90% water • Includes many dissolved substances • Nutrients • Salts (electrolytes) • Respiratory gases • Hormones • Plasma proteins • Waste products

  8. Blood Plasma • Plasma proteins • Most abundant solutes in plasma • Most plasma proteins are made by liver • Various plasma proteins include • Albumin—regulates osmotic pressure • Clotting proteins—help to stem blood loss when a blood vessel is injured • Antibodies—help protect the body from pathogens

  9. Blood Plasma • Acidosis • Blood becomes too acidic • Alkalosis • Blood becomes too basic • In each scenario, the respiratory system and kidneys help restore blood pH to normal

  10. Formed Elements • Erythrocytes • Red blood cells (RBCs) • Leukocytes • White blood cells (WBCs) • Platelets • Cell fragments

  11. Photomicrograph of a Blood Smear Figure 10.2

  12. Characteristics of Formed Elements of the Blood Table 10.2 (1 of 2)

  13. Characteristics of Formed Elements of the Blood Table 10.2 (2 of 2)

  14. Formed Elements • Erythrocytes (red blood cells or RBCs) • Main function is to carry oxygen • Anatomy of circulating erythrocytes • Biconcave disks • Essentially bags of hemoglobin • Anucleate (no nucleus) • Contain very few organelles • 5 million RBCs per cubic millimeter of blood

  15. Formed Elements • Hemoglobin • Iron-containing protein • Binds strongly, but reversibly, to oxygen • Each hemoglobin molecule has four oxygen binding sites • Each erythrocyte has 250 million hemoglobin molecules • Normal blood contains 12–18 g of hemoglobin per 100 mL blood

  16. Formed Elements • Homeostatic imbalance of RBCs • Anemia is a decrease in the oxygen-carrying ability of the blood • Sickle cell anemia (SCA) results from abnormally shaped hemoglobin • Polycythemia is an excessive or abnormal increase in the number of erythrocytes

  17. Formed Elements Table 10.1

  18. Formed Elements Figure 10.3

  19. Formed Elements • Leukocytes (white blood cells or WBCs) • Crucial in the body’s defense against disease • These are complete cells, with a nucleus and organelles • Able to move into and out of blood vessels (diapedesis) • Can move by ameboid motion • Can respond to chemicals released by damaged tissues • 4,000 to 11,000 WBC per cubic millimeter of blood

  20. Formed Elements • Abnormal numbers of leukocytes • Leukocytosis • WBC count above 11,000 leukocytes/mm3 • Generally indicates an infection • Leukopenia • Abnormally low leukocyte level • Commonly caused by certain drugs such as corticosteroids and anticancer agents • Leukemia • Bone marrow becomes cancerous, turns out excess WBC

  21. Formed Elements • Types of leukocytes • Granulocytes • Granules in their cytoplasm can be stained • Possess lobed nuclei • Include neutrophils, eosinophils, and basophils • Agranulocytes • Lack visible cytoplasmic granules • Nuclei are spherical, oval, or kidney-shaped • Include lymphocytes and monocytes

  22. List of the WBCs from most to least abundant Neutrophils Lymphocytes Monocytes Eosinophils Basophils Easy way to remember this list Never Let Monkeys Eat Bananas Formed Elements

  23. Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Basophils Erythrocytes Platelets Eosinophils Lymphocytes Monocytes Neutrophils Formed Elements Figure 10.4

  24. Hemocytoblaststem cells Formed Elements Figure 10.4, step 1

  25. Hemocytoblaststem cells Lymphoidstem cells Secondary stem cell Formed Elements Figure 10.4, step 2

  26. Hemocytoblaststem cells Lymphoidstem cells Secondary stem cell Lymphocytes Formed Elements Figure 10.4, step 3

  27. Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Lymphocytes Formed Elements Figure 10.4, step 4

  28. Hemocytoblaststem cells Lymphoidstem cells Myeloidstem cells Secondary stem cells Basophils Erythrocytes Platelets Eosinophils Lymphocytes Monocytes Neutrophils Formed Elements Figure 10.4, step 5

  29. Formed Elements • Types of granulocytes • Neutrophils • Multilobed nucleus with fine granules • Act as phagocytes at active sites of infection • Eosinophils • Large brick-red cytoplasmic granules • Found in response to allergies and parasitic worms

  30. Formed Elements • Types of granulocytes (continued) • Basophils • Have histamine-containing granules • Initiate inflammation

  31. Formed Elements • Types of agranulocytes • Lymphocytes • Nucleus fills most of the cell • Play an important role in the immune response • Monocytes • Largest of the white blood cells • Function as macrophages • Important in fighting chronic infection

  32. Formed Elements • Platelets • Derived from ruptured multinucleate cells (megakaryocytes) • Needed for the clotting process • Normal platelet count = 300,000/mm3

  33. Hematopoiesis • Blood cell formation • Occurs in red bone marrow • All blood cells are derived from a common stem cell (hemocytoblast) • Hemocytoblast differentiation • Lymphoid stem cell produces lymphocytes • Myeloid stem cell produces all other formed elements

  34. Hematopoiesis Figure 10.4

  35. Formation of Erythrocytes • Unable to divide, grow, or synthesize proteins • Wear out in 100 to 120 days • When worn out, RBCs are eliminated by phagocytes in the spleen or liver • Lost cells are replaced by division of hemocytoblasts in the red bone marrow

  36. Control of Erythrocyte Production • Rate is controlled by a hormone (erythropoietin) • Kidneys produce most erythropoietin as a response to reduced oxygen levels in the blood • Homeostasis is maintained by negative feedback from blood oxygen levels

  37. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance IncreasedO2- carryingability of blood Reduced O2levels in blood MoreRBCs Kidney releaseserythropoietin Enhancederythropoiesis Erythropoietinstimulates Red bonemarrow Control of Erythrocyte Production Figure 10.5

  38. Normal blood oxygen levels Control of Erythrocyte Production Figure 10.5, step 1

  39. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance Control of Erythrocyte Production Figure 10.5, step 2

  40. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance Reduced O2levels in blood Control of Erythrocyte Production Figure 10.5, step 3

  41. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance Reduced O2levels in blood Kidney releaseserythropoietin Control of Erythrocyte Production Figure 10.5, step 4

  42. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance Reduced O2levels in blood Kidney releaseserythropoietin Erythropoietinstimulates Red bonemarrow Control of Erythrocyte Production Figure 10.5, step 5

  43. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance Reduced O2levels in blood MoreRBCs Kidney releaseserythropoietin Enhancederythropoiesis Erythropoietinstimulates Red bonemarrow Control of Erythrocyte Production Figure 10.5, step 6

  44. Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels IncreasedO2- carryingability of blood Reduced O2levels in blood MoreRBCs Kidney releaseserythropoietin Enhancederythropoiesis Erythropoietinstimulates Red bonemarrow Control of Erythrocyte Production Figure 10.5, step 7

  45. Imbalance Stimulus: DecreasedRBC count, decreasedavailability of O2 toblood, or increasedtissue demands for O2 Normal blood oxygen levels Imbalance IncreasedO2- carryingability of blood Reduced O2levels in blood MoreRBCs Kidney releaseserythropoietin Enhancederythropoiesis Erythropoietinstimulates Red bonemarrow Control of Erythrocyte Production Figure 10.5, step 8

  46. Formation of White Blood Cells and Platelets • Controlled by hormones • Colony stimulating factors (CSFs) and interleukins prompt bone marrow to generate leukocytes • Thrombopoietin stimulates production of platelets

  47. Hemostasis • Stoppage of bleeding resulting from a break in a blood vessel • Hemostasis involves three phases • Vascular spasms • Platelet plug formation • Coagulation (blood clotting)

  48. Hemostasis Figure 10.6

  49. Hemostasis • Vascular spasms • Vasoconstriction causes blood vessel to spasm • Spasms narrow the blood vessel, decreasing blood loss

  50. Step 1: Vascular Spasms Step 2:Platelet Plug Formation Step 3:Coagulation Injury to liningof vessel exposescollagen fibers;platelets adhere Plateletplugforms Fibrin clot withtrapped redblood cells Collagenfibers Fibrin Platelets Platelets release chemicalsthat attract more platelets tothe site and make nearbyplatelets sticky PF3 fromplatelets Calciumand otherclottingfactorsin bloodplasma + Tissue factorin damagedtissue Phases ofcoagulation(clottingcascade) Formation ofprothrombinactivator Prothrombin Thrombin Fibrin(insoluble) Fibrinogen(soluble) Hemostasis Figure 10.6

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