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severe anemia again - pcr
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08-06-2006, 11:56 AM
An increase in which of the following best explains the mechanism
by which the cardiac output increases in severe anemia? A. Arteriolar diameter B. Blood viscosity C. Peripheral vascular resistance D. Splanchnic blood flow E. Tissue oxygen tension
08-06-2006, 12:55 PM
A....eventually will cause high output cardiac faliure !!
08-06-2006, 01:18 PM
In severe anemia, diminished transport of oxygen in the blood leads to hypoxia in the tissues. The hypoxia (compare to choice E) causes small arteries and arterioles to dilate, which allows greater-than-normal amounts of blood to return to the heart. In severe anemia, the viscosity of blood (choice B) may decrease by 50% or more because blood viscosity depends largely on the concentration of red blood cells. This decrease in viscosity lowers the resistance to blood flow in the peripheral tissues (i.e., decreases peripheral vascular resistance, choice C) allowing even greater amounts of blood to return to the heart.
Blood is often shunted away from the splanchnic vascular bed (choice D) in anemia, which can cause gastrointestinal problems |
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