Physiology Chapters 15: Cardiovascular - Blood

Front 1

I. Overview of the Composition of Blood: The Hematocrit (3)

Back 1

-Blood = vehicle for transport
-Average blood volume
=Women = 5.0 L
=Men = 5.5 L
-Components of blood
=Plasma
=Erythrocytes
=Leukocytes
=Platelets

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Hematocrit (2)

Back 2

Percentage of red blood cells in whole blood

Men = 42–52
Women = 37–47

Front 3

II. Plasma (5)
Made of?

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-90% water
-6–8% proteins
-Electrolytes
=Relatively high concentrations of Na+ and Cl-
=Relatively low concentrations of H+, HCO3-, K+, and Ca2+

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Plasma (4)
Consists of?

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-Nutrients: glucose, amino acids, lipids, and vitamins
-Wastes: urea, bilirubin, and creatinine
-Gases (dissolved): oxygen and carbon dioxide
-Hormones

Front 5

Plasma Proteins (2)
-Three classes

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-Three classes
=Albumins
=Globulins
=Fibrinogen
-Synthesized in liver, except some globulins synthesized by lymphocytes

Front 6

Albumins: Functions (2)

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-Major contributor to plasma oncotic osmotic pressure
-Carriers

Front 7

Globulins: Functions (7)

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-Alpha and Beta
=Carriers
=Clotting factors
=Enzymes
=Precursor proteins (angiotensinogen)
-Gamma = immunoglobulins
=Part of immune system

Front 8

Fibrinogen: Function

Back 8

Blood clotting

Front 9

Erythrocytes (7)

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-5 billion RBCs / mL blood
-Shape—biconcave disk
=Large surface area
=Favors diffusion
-Diameter = 8 mm
-Thickness = 2 mm
-Flexible membrane
-No nucleus nor organelles
=No mitochondria
=No anaerobic glycolysis
-Major function—transport oxygen and carbon dioxide

Front 10

Hemoglobin Molecule (7)

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-Molecule = globin + 4 heme groups
=Globin = 4 chains of polypeptides
=Heme = an iron containing group
-Greatly increases O2 transport
=98.5% of transported O2 is bound to Hb
=1.5% of transported O2 is dissolved in plasma
-Also binds to CO2, H+, and CO

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Hemoglobin Molecule (6)

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-Oxygenated Hb is bright red
-Deoxygenated Hb is very dark red (almost black)
-Oxygen binds to iron portion of hemoglobin
=Oxyhemoglobin

-Carbon dioxide binds to amino acid portion
=Carbaminohemoglobin

-Carbon monoxide - can be deadly
=Preferentially binds to iron of hemoglobin
+Carboxyhemoglobin

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Life Cycle of Erythrocyte (6)

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-No DNA, RNA, or organelles
-No division of mature RBCs
-Short life span = 120 days
-Replace 2–3 million RBCs/second
= 200 billion/day
-Synthesized in red bone marrow
Erythropoiesis
-Filtered by spleen (and liver)

Front 13

Erythrocyte Production (4)

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-Erythrocytes and leukocytes develop from same stem cells in bone marrow
=Hematopoietic stem cells
-Erythrocyte synthesis stimulated by erythropoietin
=Secreted from kidneys under conditions of low oxygen levels in blood flowing to kidneys

Front 14

Requirements for Erythrocyte Production (9)

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-Iron
=Component of hemoglobin (heme portion)
=Normal hemoglobin content of blood
+Men: 13–18 gram / dL
+Women: 12–16 gram / dL
-Folic acid
=Necessary for DNA replication, thus cell proliferation
-Vitamin B12
=Necessary for DNA replication, thus cell proliferation

Front 15

Anemia

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Decrease in the oxygen-carrying capacity of blood

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Dietary anemia

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-Iron: iron-deficiency anemia
-Vitamin B12: pernicious anemia

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Hemorrhagic anemia

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Bleeding

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Hemolytic anemia

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-Malaria
-Sickle cell anemia

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Aplastic anemia

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Bone marrow defect

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Renal anemia

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Kidney disease

Front 21

Spleen (7)

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-Spleen macrophages filter blood by phagocytosis of old fragile RBCs
-Hemoglobin catabolized
=After iron removed, heme  bilirubin
=Bilirubin released into bloodstream
=Travels to liver for further metabolism
=Products of bilirubin catabolism secreted in bile to intestinal tract or released into bloodstream and excreted in urine
-Iron recycled for synthesis of new hemoglobin

Front 22

Leukocytes (5)
Types

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-Neutrophils
-Eosinophils
-Basophils
-Monocytes
-Lymphocytes

Front 23

Leukocytes (5)
Function

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-Function in defense of body
=Immune system
=Defend against pathogens
=Identify and destroy cancer cells
=Phagocytosis of debris from dead or injured cells

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Classification of Leukocytes (2)

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-Granulocytes—cytoplasmic granules
=Neutrophils—red and blue staining granules
=Eosinophils—red staining granules
=Basophils—blue staining granules
-Agranulocytes—no cytoplasmic granules
=Monocytes
=Lymphocytes

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Neutrophil (3)

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-50–80% of leukocytes in blood
-Phagocyte
-Numbers increase during infections - bacterial

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Eosinophil (3)

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-1–4% of leukocytes
-Phagocytes (but not main mechanism of action)
-Defend against parasitic invaders (e.g., parasitic worms)
-Granules contain toxic molecules that attack parasites

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Basophil (3)

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<1% of leukocytes
Non-phagocytic
Contribute to allergic reactions
=Histamine
=Heparin

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Monocyte (3)

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-5% of leukocytes
-Phagocytes
-Migrate to tissues and become macrophages
=Wandering macrophages
=Fixed macrophages

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Lymphocyte (3)

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-30% of leukocytes
-99% of interstitial fluid cells
-Three types
=B lymphocytes (B cells)
=T lymphocytes (T cells)
=Null cells

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B Cells (4)

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-B cells associated with antibodies
-B cell contacts antigen  plasma cell
-Plasma cell secretes antibodies (immunoglobulins)
-Antibodies mark invaders for destruction

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T Cells (3)

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-Directly damage foreign cells
-T cells contact infected, mutant or transplanted cells
-Develop into cytotoxic T cells that destroy target cell
=Takes several days
=Secretory products form pores in target cell membrane
=Lysis

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Null Cells (4)

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-Most are natural killer cells
-Important against viral infections
-Attack virus-infected cells—cause lysis
-Fast acting—early immune response

Front 33

Three Mechanisms of Hemostasis (3)
Hemostasis = stop bleeding

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Hemostasis = stop bleeding
Vascular spasm
Formation of platelet plug
Blood coagulation

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Vascular Spasm (5)

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-Damage blood vessel
-Vessel constricts to minimize blood loss
=Intrinsic vascular response
=Sympathetic innervation
-Endothelial layer becomes sticky

Front 35

Formation of a Platelet Plug (3)

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-Forms around site of vessel damage
-Decreases blood loss
-Necessary for production of a blood clot

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Platelets

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Cytoplasmic fragments derived from megakaryocytes, also called thrombocytes

Front 37

Platelet Components (4)

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-Cell fragments
=No nucleus
=Has organelles and granules
-100,000 – 500,000 / mL blood
-Important in blood clotting
-Granules containing secretory products

Front 38

Platelet Plug Formation
First Step: Platelet Adhesion

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Blood Vessel Damage --> Exposure of Subendothelium --> vWf Binds to Collagen Fibers --> Platelets Bind to vWf --> Platelet Adhesion Or Secretions

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Platelet Plug Formation
Second Step: Aggregation (5)

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-Aggregated platelets release secretory products
=ADP—increases stickiness (+ feedback)
=Serotonin—vasoconstriction
=Epinephrine—vasoconstriction
=Chemicals to facilitate blood coagulation

Front 40

Preventing the Spread of a Platelet Plug (5)

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-Chemicals that prevent platelet aggregation
-Prostacyclin (PGI2)
=Produced in healthy endothelial cells
-Nitric oxide
=Released by healthy endothelial cells

Front 41

Clot Formation

Back 41

Fibrinogen --> Fibrin (loose) --> Fibrin (mesh)
(Fibrin clot = blood clot)

Front 42

Clotting Factors (5)

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-Clotting factors produced by liver
=Secreted into blood in inactive form
=Activated during cascade
-Plasma without clotting factors = serum
-Hemophilia = genetic disorder, deficiency in clotting factor, usually Factor VIII

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Dissolving Clot

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Requires another cascade initiated by exposure of collagen
Plasminogen --> (plasminogen activators) Plasmin --> Dissolves Clot

Front 44

Role of Coagulation Factors in Clot Formation Disorders

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-Hemophilia
=Genetic disorder caused by deficiency of gene for specific coagulation factor
-Von Willebrand’s disease
=Reduced levels of vWf
=Decreases platelet plug formation
-Vitamin K deficiencies
=Decreased synthesis of clotting factors

Front 45

Anticoagulants agents (5)

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-Clotting can be prevented by Ca+2 chelators (sodium citrate or EDTA (ethylenediaminetetraacetic acid)

-Heparin (Lovenox)
=Activates antithrombin III (text) blocks prothrombin

-Coumadin (warfarin)
=Once used as rat poison
=Inhibits action of vitamin K (thus II, VII,IX, X)

-Aspirin
=Inhibits Cox-1. Reduces stickiness of platelets/platelet aggregation