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Blood

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Title: Blood


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
Fig.19.01
6
Formed Elements
  • Erythrocytes (a.k.a. red blood cells)
  • 4 to 6 million per mm3 (mL)
  • About 7 - 8 mm 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

7
Formed elements
Fig.19.02
8
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

9
Development of blood cells
Fig. 19.03
10
The anatomy of an erythrocyte the hemoglobin
molecule
11
Hemoglobin (Hb)
  • Each RBC contains an average of 250 million Hb
    molecules
  • Each Hb molecule has 4 oxygen binding sites
  • Thats about 1 billion oxygen molecules per RBC!
  • CO (carbon monoxide) has approximately 200 times
    the affinity for Hb than oxygen and it fool O2
    saturation detectors

12
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

13
RBC catabolism continued
  • The rest of the heme molecule
  • First converted to biliverdin (it is green)
  • Then to bilirubin (it is yellow-orange)
  • Its 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)

14
RBC life cycle
Fig. 19.05
15
Erythrocyte disorders
  • Anemia polycythemia

16
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

17
Anemia Decreased Hemoglobin Content
  • 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 B12
  • Lack of intrinsic factor needed for absorption of
    B12
  • Treatment is intramuscular injection of B12

18
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

19
Polycythemia
  • Polycythemia excess RBCs that increase blood
    viscosity
  • Three main polycythemias are
  • Polycythemia vera
  • Secondary polycythemia
  • Blood doping

20
Sickle Cell Disease
21
RBC homeostasis
22
Leukocytes
  • White blood cells are important for bodily
    defenses and immunity
  • 2 General categories
  • Granulocytes
  • Neutrophils
  • Eosinophils
  • Basophils
  • Agranulocytes
  • Lymphocytes
  • Monocytes

23
Granulocytes
  • Granulocytes neutrophils, eosinophils, and
    basophils
  • Contain cytoplasmic granules that stain
    specifically (acidic, basic, or both) with
    Wrights stain
  • Are larger and usually shorter-lived than RBCs
  • Have lobed nuclei
  • Are all phagocytic cells

24
Neutrophils
  • 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 bodys bacteria slayers

25
Eosinophils
  • Eosinophils account for 14 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 bodys counterattack against parasitic
    worms
  • Lessen the severity of allergies by phagocytizing
    immune complexes

26
Basophils
  • 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)

27
Agranulocytes
  • 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

28
Lymphocytes
  • 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

29
Monocytes
  • Monocytes account for 48 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

30
Monocytes
  • Macrophages
  • Are highly mobile and actively phagocytic
  • Activate lymphocytes to mount an immune response

31
Leukocytes
32
Chemotaxis of neutrophils
33
Leukocyte Disorders
  • Leukemia
  • Acute uncontrolled production of immature WBCs.
  • Chronic accumulation of mature WBCs in the blood

34
Leukocytes Disorders Leukemias
  • 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

35
Leukemia
  • 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

36
Hemostasis clotting
  • Involves
  • platelets (fragments of megakaryocytes)
  • Proteins Fibers (Thrombin Fibrin)
  • Clotting factors

37
Platelet plug formation
38
Plug formation
39
Clotting
40
Hemostasis DisordersThromboembolytic Conditions
  • 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

41
Hemostasis DisordersThromboembolytic Conditions
  • 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

42
Prevention of Undesirable Clots
  • Substances used to prevent undesirable clots
    include
  • Aspirin an antiprostaglandin that inhibits
    thromboxane A2
  • Heparin an anticoagulant used clinically for
    pre- and postoperative cardiac care
  • Warfarin used for those prone to atrial
    fibrillation

43
Hemostasis Disorders Bleeding Disorders
  • 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/mm3 is
    diagnostic for this condition
  • Treated with whole blood transfusions

44
Hemostasis Disorders Bleeding Disorders
  • 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

45
Hemostasis Disorders Bleeding Disorders
  • 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

46
Hemostasis Disorders Bleeding Disorders
  • Symptoms include prolonged bleeding and painful
    and disabled joints
  • Treatment is with blood transfusions and the
    injection of missing factors

47
Blood typing ABO groups
48
ABO groups by frequency in US population
49
Rh factor
50
Blood Transfusions
  • 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
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