BIO_211_Ch17_Lecture Notes Blood

BIO_211_Ch17_Lecture Notes Blood - Bio 211 A & P II Ch...

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Bio 211 Ch 17 Blood 1 Chapter 17 Blood Blood Composition Blood: a fluid connective tissue composed of Plasma Formed elements Erythrocytes (red blood cells, or RBCs) Leukocytes (white blood cells, or WBCs) Platelets Blood Composition Hematocrit Percent of blood volume that is RBCs 47% ± 5% for males 42% ± 5% for females Physical Characteristics and Volume Sticky, opaque fluid Color scarlet to dark red pH 7.35–7.45 38 ° C ~8% of body weight Average volume: 5–6 L for males, and 4–5 L for females Functions of Blood 1 Distribution of O 2 and nutrients to body cells Metabolic wastes to the lungs and kidneys for elimination Hormones from endocrine organs to target organs Functions of Blood 2 Regulation of Body temperature by absorbing and distributing heat Normal pH using buffers Adequate fluid volume in the circulatory system Functions of Blood 3 Protection against Blood loss Plasma proteins and platelets initiate clot formation Infection Antibodies Complement proteins WBCs defend against foreign invaders
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Bio 211 Ch 17 Blood 1 Blood Plasma 90% water Proteins are mostly produced by the liver 60% albumin 36% globulins 4% fibrinogen Blood Plasma Nitrogenous by-products of metabolism—lactic acid, urea, creatinine Nutrients—glucose, carbohydrates, amino acids Electrolytes—Na + , K + , Ca 2+ , Cl , HCO 3 Respiratory gases—O 2 and CO 2 Hormones Formed Elements Only WBCs are complete cells RBCs have no nuclei or organelles Platelets are cell fragments Most formed elements survive in the bloodstream for only a few days Most blood cells originate in bone marrow and do not divide Erythrocytes Biconcave discs, anucleate, essentially no organelles Filled with hemoglobin (Hb) for gas transport Contain the plasma membrane protein spectrin and other proteins Provide flexibility to change shape as necessary Are the major factor contributing to blood viscosity Erythrocytes Structural characteristics contribute to gas transport Biconcave shape—huge surface area relative to volume >97% hemoglobin (not counting water) No mitochondria; ATP production is anaerobic; no O 2 is used in generation of ATP A superb example of complementarity of structure and function! Erythrocyte Function RBCs are dedicated to respiratory gas transport Hemoglobin binds reversibly with oxygen Erythrocyte Function Hemoglobin structure Protein globin: two alpha and two beta chains Heme pigment bonded to each globin chain
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Bio 211 Ch 17 Blood 1 Iron atom in each heme can bind to one O 2 molecule Each Hb molecule can transport four O 2 Hemoglobin (Hb) O 2 loading in the lungs Produces oxyhemoglobin (ruby red) O 2 unloading in the tissues Produces deoxyhemoglobin or reduced hemoglobin (dark red) CO
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This note was uploaded on 10/16/2011 for the course SCIENCE Bio 211 taught by Professor Dr.frederickduss during the Spring '11 term at Midlands Tech.

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BIO_211_Ch17_Lecture Notes Blood - Bio 211 A & P II Ch...

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