SC BIOL 244 - Ch. 17 Blood Part 2 (6 pages)

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BIOL 244 Chapter 17 Blood Lecture 8 September 16 Erythrocytes RBCs Disc shaped cell with thick rim No mitochondria Anaerobic fermentation to produce ATP Functions Carry oxygen from lungs to cell tissues Pick up carbon dioxide from tissues and bring to lungs Blood type determined by surface proteins and glycolipids Erythrocytes and hemoglobin concentration indicate amount of oxygen blood can carry Hematocrit packed cell volume percentage of whole blood volume composed of erythrocytes Men 42 52 Women 37 48 Hemoglobin concentration of whole blood Men 13 18 g dL Women 12 16 g dL Hemoglobin Hb Structure Globin formed by 4 protein chains 2 alpha and 2 beta chains 4 heme groups nonprotein moiety that binds O2 to ferrous ion Fe2 at its center Erythrocyte production erythropoiesis 2 5 million RBCs produced per second Kidney production of erythropoietin stimulates bone marrow Development takes 3 5 days Average lifespan of about 120 days Stimuli for increasing erythropoiesis Low levels of oxygen hypoxemia High altitude Increase in exercise Anemia 3 categories Inadequate erythropoiesis or hemoglobin synthesis Kidney failure and insufficient erythropoietin Iron deficiency anemia Pernicious anemia inadequate vitamin B12 from poor nutrition or lack of intrinsic factor Hypoplastic anemia slowing of erythropoiesis Aplastic anemia complete cessation of erythropoiesis body cannot make RBCs Hemorrhagic anemias from bleeding Hemolytic anemias from erythrocyte destruction Sickle Cell Disease Anemia Hereditary hemoglobin defects occur mostly among people of African descent Caused by a recessive allele that modifies the structure of the hemoglobin molecule Hbs Differs only on the 6th amino acid of the beta chain HbS does not bind oxygen well Erythrocytes become rigid sticky pointed at ends Clump together and block small blood vessels causing intense pain Can lead to kidney or heart failure stroke rheumatism or paralysis Blood types are based on interactions between antigens and antibodies