2 alpha and 2 beta chains fetal Hb gamma replace beta chains binds O 2 beter

2 alpha and 2 beta chains fetal hb gamma replace beta

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2 alpha and 2 beta chains fetal Hb - gamma replace beta chains; binds O 2 beter Heme Group ring with iron atom inside Alpha Beta Heme groups Blood - 12
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Hemoglobin (Hb) Structure Heme group conjugated with each protein chain hemoglobin molecule can carry four O 2 binds oxygen to ferrous ion (Fe 2+ ) CH 3 CH CH 2 C C HC C C CH N CH C C C C CH 3 3 N Fe 2+ N CH 2 C C CH CH 2 C N C CH 2 HC C C CH COOH C C CH 2 Fe 2+ O=O Blood - 13
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Clinical Correlates Carbon Monoxide Poisoning Carbon monoxide binds to hemoglobin much more strongly than oxygen It creates low oxygen conditions in tissue (hypoxia) It is hard to detect because carboxyhemoglobin is very red Blood - 14
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Erythrocytes and Hemoglobin RBC count and hemoglobin concentration indicate amount of O 2 blood can carry Hematocrit (packed cell volume) - % of blood composed of cells men 42- 52% cells; women 37- 48% cells RBC count men 4.6-6.2, women 4-2-5.4 million/ L Values are lower in women androgens stimulate RBC production women have periodic menstrual losses Blood - 15
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Clinical Correlates Anemia Blood - 16 Anemia is insufficient RBS’s or hemoglobin in the blood Inadequate erythropoiesis or hemoglobin synthesis causes pe r niciou s anemia inadequate vitamin B 12 iron-deficiency anemia kidney failure and insufficient erythropoietin Thalassemia – recessive genetic disease of globin aplastic anemia - complete cessation Hemorrhagic anemias Hemolytic anemias
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Physiology Objective: The creation of large numbers of blood cells is crucial to maintaining homeostasis, and pathologies of blood cell generation have important physiological consequences Blood - 17
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Hemopoiesis Adult produces 400 billion platelets, 200 billion RBCs and 10 billion WBCs every day Hemopoietic tissues produce blood cells Liver stops producing blood cells at birth Spleen remains involved with WBC production lymphoid hemopoiesis occurs in widely distributed lymphoid tissues, makes lymphocytes Red bone marrow pluripotent stem cells create all blood cells Blood - 18
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Erythrocyte Homeostasis Blood - 19 Stimulus for erythropoiesis Hypoxemia - nadequate oxygen transport Sensed by liver and kidneys Erythropoietin secreted (85% kidneys) Cell division is stimulated Hypoxemia liver and kidneys Secretion of EPO Increased RBC count Increased O 2 transport Stimulation of red marrow 3-4 days
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Nutritional Needs for Erythropoiesis Iron - key nutritional requirement lost daily through urine, feces, and bleeding men 0.9 mg/day and women 1.7 mg/day low absorption requires consumption of 5-20 mg/day dietary iron: ferric (Fe 3+ ) and ferrous (Fe 2+ ) stomach acid converts Fe 3+ to absorbable Fe 2+ some foods interfere with this Blood - 20
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Gastroferritin Mixture of Fe 2+ and Fe 3+ is ingested 1 Stomach acid converts Fe 3+ to Fe 2+ 2 3 4 Fe 2+ Gastroferritin Fe 2+ binds to gastroferritin Gastroferritin transports Fe 2+ to small intestine and releases it for absorption Fe 3+ Blood - 21
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