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Bio186 A&P2 Unit 1: Cardiovascular System: Blood Cardiovascular System: Blood Hematology the study of blood A. Functions 1. Transport: cells, nutrients, wastes, hormones, gases, heat 2. Regulation: pH, electrolyte levels, heat distribution 3. Protection: defense against pathogens; limit fluid loss from damaged vessels B. General Properties 1. Connective tissue specialized cells embedded in fluid matrix (plasma) with dissolved protein fibers (fibrinogen, etc.) ~ 55% Plasma ~ 45% Formed Elements = cells & cell fragments suspended in the plasma. 2. Volume depends on size, sex, age. 5-6 L adult (5.3-6.4 qt) 4-5 L adult female (4.2-5.3 qt) 3. pH: slightly alkaline. 7.35-7.45 (tightly regulated by buffers) 4. Five-times as viscous as water. C. Plasma ~92% water Similar, but not identical to interstitial fluid (more protein & oxygen than ISF) Dissolved solutes: 1. Proteins a. Albumins most abundant; gives blood its osmotic pull; transport other molecules and/or ions. b. Globulins antibodies transport proteins carry other molecules, ions, hormones that otherwise have low solubility ( e.g. cholesterol) c. Clotting proteins e.g. prothrombin, fibrinogen d. Enzymes, hormones, etc . 2. Nitrogen wastes e.g. urea 3. Nutrients e.g. glucose, amino acids, fatty acids, glycerol 4. Electrolytes e.g. Na + , K + , Ca ++ , Mg ++ , H + , Cl 5. Respiratory gases O 2 and CO 2 Bio186 A&P2 Unit 1: Cardiovascular System: Blood D. Formed Elements Hemopoiesis or hematopoiesis production of the various formed elements by process of (1) cell division and (2) differentiation (specialization, maturation) occurs in red bone marrow (a.k.a. myeloid tissue) = vertebrae, sternum, ribs, scapulae, pelvis, proximal limb bones Hematocrit Percentage of whole blood volume taken up by formed elements (mostly RBCs). 1. Erythrocytes (Red Blood Cells; RBCs) a. Numbers Make up about 45% of whole blood volume Make up 99.9% of formed elements approx. 4-6 million/l (mm 3 ) of blood b. Structure Bi-concave discs thin center, thick margin (1) gives large surface:volume ratio = diffusion (2) enabled RBC to bend & flex through narrow capillaries Mature RBCs = no nucleus (no ribosomes, no mitochondria) c. Hemoglobin 95% of RBC proteins 4 subunits; each subunit contains: globin protein chain heme = an organic pigment atom of iron a binding site for one oxygen molecule High [O 2 ] in plasma (e.g. in lungs) O 2 binds to heme Low [O 2 ] in plasma (e.g. peripheral tissues) O 2 released High [CO 2 ] in plasma CO 2 binds to globin portion d. Life Cycle i. Erythropoiesis = RBC production occurs in red bone marrow stimulated by hormone: Erythropoietin (EPO) kidney secretes EPO in response to low blood O 2 ii. Lifespan = ~120 days iii. Destruction & Hemoglobin recycling Majority (90%) of aged RBCs mechanically tested in small capillaries ... View Full Document

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