04缺氧（04 hypoxia）.docVIP

04缺氧（04 hypoxia） Four, Jane answer 1. hypoxia can be divided into several types? What is the basis for classification? What are the characteristics of blood oxygen changes in all types? [answer] according to the causes of hypoxia and changes in blood oxygen, hypoxia is generally divided into four types: hypotonic, blood, circulatory and tissue hypoxia 2. try to explain the mechanism of hypoxia caused by CO poisoning Answer [points] (1) CO and Hb is 210 times larger than the oxygen affinity, Hb and CO combined with the formation of carboxyhemoglobin and lose the ability to carry oxygen; (2) CO inhibited glycolysis in erythrocytes, reduced the production of 2 and 3-DPG, shifted the left oxygen curve, prevented the release of oxygen from oxygenated hemoglobin, and aggravated the hypoxia in tissues (3) when the CO binds to one of the heme molecules in the Hb molecule, it increases the affinity of the remaining three heme pairs, leaving the oxygen shift from the curve to the left 3. describe the mechanism of circulatory hypoxia and the characteristics of blood oxygen changes Answer [points] simple cycle of hypoxia, blood pressure, oxygen saturation and oxygen content is normal. The slow caused by ischemia or congestion of blood, the blood flows through the capillary is prolonged, cells from the blood oxygen uptake per unit volume increased, caused by venous oxygen content decreased, arteriovenous oxygen content difference increases; but the total amount of blood supply to tissues decreased, total oxygen diffusion to tissue cells still can not meet the needs and cell hypoxia. 4. try to explain the mechanism of hypoxia caused by cyanide poisoning [] the most typical organization answer points of cyanide poisoning poisoning can cause hypoxia. Such as HCN, KCN, NaCN, cyanide and NH4CN by the digestive tract, respiratory tract or skin to enter the body, ferric and rapidly oxidized cytochrome oxidase with high iron cyanide cytochrome oxidase, which cannot be reduced into cells