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Blood Chapter 19. Functions of blood Transportation –Oxygen –Carbon dioxide –Nutrients & Hormones –Wastes Regulation –Fluid balance & Thermoregulation.

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Presentation on theme: "Blood Chapter 19. Functions of blood Transportation –Oxygen –Carbon dioxide –Nutrients & Hormones –Wastes Regulation –Fluid balance & Thermoregulation."— Presentation transcript:

1 Blood Chapter 19

2 Functions of blood Transportation –Oxygen –Carbon dioxide –Nutrients & Hormones –Wastes Regulation –Fluid balance & Thermoregulation –pH & Electrolytes Protection –Immune System & bodies defenses –Clotting and wound repair

3 Physical characteristics of Blood Yes, it is thicker than water pH between 7.35 (venous) and 7.45 (arterial) Volume –5 to 6 liters in an average male (1.5 gal or 12 pints) –4 to 6 liters in an average female (1.2 gal or 10 pints) About 20% of the extracellular fluid About 8% of the body mass

4 Composition of Blood Whole blood is divided into plasma and formed elements Plasma: –55% of whole blood volume –91.5% water –7% soluble proteins Albumin = 54% (osmotic balance, buffering, transport of steroid hormones and fatty acids) Globulins = 38% (antibodies, etc) Fibrinogen = 7% (produced by liver, for clotting) 1% other –Other solutes Electrolytes, gases, nutrients, wastes, hormones

5 Composition of Blood

6 Extracellular Fluids Interstitial fluid (IF) and plasma Materials plasma and IF exchange across capillary walls: –water –ions –small solutes

7 Plasma

8 3 Classes of Plasma Proteins Albumins (60%) Globulins (35%) Fibrinogen (4%)

9 Origins of Plasma Proteins 90% made in liver Antibodies made by plasma cells Peptide hormones made by endocrine organs

10 Formed Elements Erythrocytes (a.k.a. red blood cells) –4 to 6 million per mm 3  L) –About  m in diameter –Anucleate –Amitotic at maturity –No mitochondria, centrioles, or much else in the way of cytoplasm. Mostly hemoglobin. –Live about 90 – 120 days Hematocrit – The total volume of blood occupied by erythrocytes. –38 – 46 % for females, average 42% –40 – 54% for males, average 47%

11 Normal Blood Counts RBC: –male: 4.5–6.3 million –female: 4.–5.5 million Hematocrit: –male: 4–52 –female: 3–47

12 Fig Formed elements

13 An Erythrocyte

14 Hemopoiesis: formation of blood cells Also known as hematopoiesis Occurs in the red marrow: –In adults, mostly in the proximal epiphysis of femur and bodies of the lumbar vertebrae –Originally from pluripotent stem cells from mesenchyme –In the fetus, hematopoiesis occurs in the liver, spleen, thymus, lymph nodes and yolk sac –Red marrow is found in the spaces of spongy bone Erythropoietin from the kidneys stimulates hematopoiesis

15 Erythrocyte development

16 Stages of RBC Maturation Myeloid stem cell Proerythroblast Erythroblasts Reticulocyte Mature RBC

17 The structure of the hemoglobin molecule

18 Hemoglobin (Hb) Each RBC contains an average of 250 million Hb molecules Each Hb molecule has 4 oxygen binding sites That’s about 1 billion oxygen molecules per RBC! CO (carbon monoxide) has approximately 200 times the affinity for Hb than oxygen and it fool O 2 saturation detectors

19 Erythrocyte catabolism After roughly 120 days red blood cells are worn out and must be recycled This occurs in the spleen and liver Iron (Fe +++ ): –The Fe +++ is removed from the heme group and bound to transferrin –It is stored in the liver, muscle and spleen by transferring it to ferritin –It can be transported on demand to the bone marrow where it can be reincorporated into new Hb

20 RBC catabolism continued The rest of the heme molecule: –First converted to biliverdin (it is green) –Then to bilirubin (it is yellow-orange) –It’s carried in the blood to the liver where it is secreted into bile –Bile is stored in the gall bladder (if you have one) and then into the small intestine –When it reaches the large intestine it is converted by bacteria into urobilinogen –Some is reabsorbed and excreted in the urine (urobilin or urochrome). The rest is in the feces (stercobilin)

21 RBC life cycle

22 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)

23 Erythrocyte disorders Anemia & polycythemia

24 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

25 Anemia: Insufficient Erythrocytes Hemorrhagic anemia – result of acute or chronic loss of blood Hemolytic anemia – prematurely ruptured erythrocytes Aplastic anemia – destruction or inhibition of red bone marrow

26 Iron-deficiency anemia results from: –A secondary result of hemorrhagic anemia –Inadequate intake of iron-containing foods –Impaired iron absorption Pernicious anemia results from: –Deficiency of vitamin B 12 –Lack of intrinsic factor needed for absorption of B 12 Treatment is intramuscular injection of B 12 Anemia: Decreased Hemoglobin Content

27 Anemia: Abnormal Hemoglobin Thalassemias – absent or faulty globin chain in hemoglobin –Erythrocytes are thin, delicate, and deficient in hemoglobin Sickle-cell anemia – results from a defective gene coding for an abnormal hemoglobin called hemoglobin S (HbS) –HbS has a single amino acid substitution in the beta chain –This defect causes RBCs to become sickle- shaped in low oxygen situations

28 Polycythemia Polycythemia – excess RBCs that increase blood viscosity Three main polycythemias are: –Polycythemia vera –Secondary polycythemia –Blood doping

29 Sickle Cell Disease

30 RBC homeostasis

31 Leukocytes White blood cells are important for bodily defenses and immunity 2 General categories: –Granulocytes Neutrophils Eosinophils Basophils –Agranulocytes Lymphocytes Monocytes

32 Granulocytes Granulocytes – neutrophils, eosinophils, and basophils –Contain cytoplasmic granules that stain specifically (acidic, basic, or both) with Wright’s stain –Are larger and usually shorter-lived than RBCs –Have lobed nuclei –Are all phagocytic cells

33 Neutrophils have two types of granules that: –Take up both acidic and basic dyes –Give the cytoplasm a lilac color –Contain peroxidases, hydrolytic enzymes, and defensins (antibiotic-like proteins) Neutrophils are our body’s bacteria slayers Neutrophils

34 Eosinophils account for 1–4% of WBCs –Have red-staining, bilobed nuclei connected via a broad band of nuclear material –Have red to crimson (acidophilic) large, coarse, lysosome-like granules –Lead the body’s counterattack against parasitic worms –Lessen the severity of allergies by phagocytizing immune complexes Eosinophils

35 Account for 0.5% of WBCs and: –Have U- or S-shaped nuclei with two or three conspicuous constrictions –Are functionally similar to mast cells –Have large, purplish-black (basophilic) granules that contain histamine Histamine – inflammatory chemical that acts as a vasodilator and attracts other WBCs (antihistamines counter this effect) Basophils

36 Agranulocytes – lymphocytes and monocytes: –Lack visible cytoplasmic granules –Are similar structurally, but are functionally distinct and unrelated cell types –Have spherical (lymphocytes) or kidney-shaped (monocytes) nuclei Agranulocytes

37 Account for 25% or more of WBCs and: –Have large, dark-purple, circular nuclei with a thin rim of blue cytoplasm –Are found mostly enmeshed in lymphoid tissue (some circulate in the blood) There are two types of lymphocytes: T cells and B cells –T cells function in the immune response –B cells give rise to plasma cells, which produce antibodies Lymphocytes

38 Monocytes account for 4–8% of leukocytes –They are the largest leukocytes –They have abundant pale-blue cytoplasms –They have purple-staining, U- or kidney-shaped nuclei –They leave the circulation, enter tissue, and differentiate into macrophages Monocytes

39 Macrophages: –Are highly mobile and actively phagocytic –Activate lymphocytes to mount an immune response Monocytes

40 Leukocytes

41 Figure 19–10 WBC Production

42 4 Colony-Stimulating Factors (CSFs) Hormones that regulate blood cell populations: 1.M-CSF: stimulates monocyte production 2.G-CSF: stimulates granulocyte production neutrophils, eosinophils, and basophils

43 4 Colony-Stimulating Factors (CSFs) 3.GM-CSF: stimulates granulocyte and monocyte production 4.Multi-CSF: accelerates production of granulocytes, monocytes, platelets, and RBCs

44 Chemotaxis of neutrophils

45 Leukocyte Disorders Leukemia –Acute: uncontrolled production of immature WBCs. –Chronic: accumulation of mature WBCs in the blood

46 Leukemia refers to cancerous conditions involving white blood cells Leukemias are named according to the abnormal white blood cells involved –Myelocytic leukemia – involves myeloblasts –Lymphocytic leukemia – involves lymphocytes Acute leukemia involves blast-type cells and primarily affects children Chronic leukemia is more prevalent in older people Leukocytes Disorders: Leukemias

47 Immature white blood cells are found in the bloodstream in all leukemias Bone marrow becomes totally occupied with cancerous leukocytes The white blood cells produced, though numerous, are not functional Death is caused by internal hemorrhage and overwhelming infections Treatments include irradiation, antileukemic drugs, and bone marrow transplants Leukemia

48 Hemostasis & clotting Involves: –platelets (fragments of megakaryocytes) –Proteins & Fibers (Thrombin & Fibrin) –Clotting factors

49 Platelets Cell fragments involved in human clotting system Nonmammalian vertebrates have thrombocytes (nucleated cells)

50 Platelet Circulation Circulates for 9–12 days Are removed by spleen 2/3 are reserved for emergencies

51 Platelet Counts 150,000 to 500,000 per microliter (mm 3 ) Thrombocytopenia: –abnormally low platelet count Thrombocytosis: –abnormally high platelet count

52 Hormonal Controls Thrombopoietin (TPO) Inteleukin-6 (IL-6) Multi-CSF

53 Hemostasis

54 The Platelet Phase Platelet aggregation (stick together): –forms platelet plug –closes small breaks

55 The Platelet Phase Platelet adhesion (attachment): –to sticky endothelial surfaces –to basal laminae –to exposed collagen fibers Platelet aggregation (stick together): –forms platelet plug –closes small breaks

56 Platelet plug formation

57 Plug formation

58 Clotting

59 The Coagulation Phase Figure 19–12a

60 Plasma Clotting Factors Table 19–4

61 Thrombus – a clot that develops and persists in an unbroken blood vessel –Thrombi can block circulation, resulting in tissue death –Coronary thrombosis – thrombus in blood vessel of the heart Hemostasis Disorders: Thromboembolytic Conditions

62 Embolus – a thrombus freely floating in the blood stream –Pulmonary emboli can impair the ability of the body to obtain oxygen –Cerebral emboli can cause strokes Hemostasis Disorders: Thromboembolytic Conditions

63 Substances used to prevent undesirable clots include: –Aspirin – an antiprostaglandin that inhibits thromboxane A 2 –Heparin – an anticoagulant used clinically for pre- and postoperative cardiac care –Warfarin – used for those prone to atrial fibrillation Prevention of Undesirable Clots

64 Thrombocytopenia – condition where the number of circulating platelets is deficient –Patients show petechiae (small purple blotches on the skin) due to spontaneous, widespread hemorrhage –Caused by suppression or destruction of bone marrow (e.g., malignancy, radiation) –Platelet counts less than 50,000/mm 3 is diagnostic for this condition –Treated with whole blood transfusions Hemostasis Disorders: Bleeding Disorders

65 Inability to synthesize procoagulants by the liver results in severe bleeding disorders Causes can range from vitamin K deficiency to hepatitis and cirrhosis Inability to absorb fat can lead to vitamin K deficiencies as it is a fat-soluble substance and is absorbed along with fat Liver disease can also prevent the liver from producing bile, which is required for fat and vitamin K absorption Hemostasis Disorders: Bleeding Disorders

66 Hemophilias – hereditary bleeding disorders caused by lack of clotting factors –Hemophilia A – most common type (83% of all cases) due to a deficiency of factor VIII –Hemophilia B – results from a deficiency of factor IX –Hemophilia C – mild type, caused by a deficiency of factor XI Hemostasis Disorders: Bleeding Disorders

67 Symptoms include prolonged bleeding and painful and disabled joints Treatment is with blood transfusions and the injection of missing factors Hemostasis Disorders: Bleeding Disorders

68 Blood typing – ABO groups

69 Figure 19–6b Cross-Reaction (a.k.a. transfusion reaction)

70 Blood Type Test Figure 19–7

71 ABO groups by frequency in US population

72 Rh factor

73 Whole blood transfusions are used: –When blood loss is substantial –In treating thrombocytopenia Packed red cells (cells with plasma removed) are used to treat anemia Blood Transfusions

74


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