Download - Chapter 14 Blood
Chapter 14Blood
Functions• transports vital substances• maintains stability of interstitial fluid• distributes heat
Blood Cells• form mostly in red bone marrow• red blood cells• white blood cells• platelets (cell fragments)
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Blood Volume
• varies with• body size• changes in fluid concentration• changes in electrolyte concentration• amount of adipose tissue
• about 8% of body weight• about 5 liters
14-3
Red Blood Cells
• erythrocytes• biconcave• one-third hemoglobin
• oxyhemoglobin• deoxyhemoglobin
• can readily squeeze through capillaries• lack nuclei and mitochondria
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Red Blood Cell Count
• number of RBCs in a cubic millimeter of blood
• 4,600,000 – 6,200,000 in males
• 4,200,000 – 5,400,000 in adult females
• 4,500,000 – 5,100,000 in children
• reflects blood’s oxygen carrying capacity
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Red Blood Cell Production
• low blood oxygen causes kidneys and liver to release erythropoietin which stimulates RBC production
• vitamin B12, folic acid and iron necessary
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Life Cycle of Red Blood Cell
• circulate for about 120 days
• macrophages in spleen and liver destroy worn out RBCs
• hemoglobin is broken down into heme and globin
• iron return to red bone marrow
• bilirubin and biliverdin excreted in bile
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White Blood Cells
• leukocytes• protect against disease• interleukins and colony-stimulating factors stimulate development
• granulocytes• neutrophils• eosinophils• basophils
• agranulocytes• lymphocytes• monocytes
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Neutrophils
• light blue granules in acid-base stain• lobed nucleus• other names
• segs• polymorphonuclear leukocyte• bands (young neutrophils)
• first to arrive at infections• phagocytic• 54% - 62% of leukocyte• elevated in bacterial infections
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Basophils
• deep blue granules is basic stain• release histamine• release heparin• less than 1% of leukocytes
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Eosinophils
• deep red granules in acid stain• bilobed nucleus• moderate allergic reactions• defend against parasitic worm infestations• 1% - 3% of leukocytes• elevated in worm infestations and allergic reactions
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Monocytes
• largest blood cell• kidney-shaped or oval nuclei• leave bloodstream to become macrophages• 3% - 9% of leukocytes• elevated in typhoid fever, malaria, tuberculosis
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Lymphocytes
• about the size of RBC• large spherical nuclei• thin rims of cytoplasm• T cells• B cells• important in immunity• produce antibodies• 25% - 33% of leukocytes• decreased T Cells in AIDS
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Diapadesis
• leukocytes squeeze through capillary walls to enter tissue space outside the blood vessel
14-18
White Blood Cell Counts
• number of WBCs per cubic millimeter of blood• 5,000 – 10,000 per cubic millimeter of blood
• leukopenia • low WBC count• typhoid fever, flu, measles, mumps, chicken pox, AIDS
• leukocytosis • high WBC count• acute infections, vigorous exercise, great loss of body fluids
• differential WBC count• lists percentages of types of leukocytes• may change in particular diseases 14-19
Blood Platelets
• thrombocytes• cell fragments of megakaryocytes• 130,000 – 360,000 per cubic millimeter of blood• helps control blood loss from broken vessels
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Blood Clots
• After forming, blood clot retracts and pulls the edges of a broken vessel together
• Platelet-derived growth factor stimulates smooth muscle cells and fibroblasts to repair damaged blood vessels
• Plasmin digests blood clots
• thrombus – abnormal blood clot• embolus – blood clot moving through blood
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Plasma Proteins
Albumins• most numerous plasma proteins• originate in liver• help maintain osmotic pressure of blood
Fibrinogen• originate in liver• plays key role in blood coagulation
Alpha and Beta Globulins• originate in liver• transport lipids and fat-soluble vitamins
Gamma Globulins• originate in lymphatic tissues• constitute the antibodies of immunity
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Gases and Nutrients
Gases• oxygen• carbon dioxide• nitrogen
Nutrients • amino acids• simple sugars• nucleotides• lipids• lipoproteins
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