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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
An increase in which of the following best explains the mechanism by which the cardiac output increases in severe anemia?
assistant
The correct answer is  In severe anemia, diminished transpo of oxygen in the blood leads to hypoxia in the tissues. The hypoxia causes small aeries and aerioles to dilate, which allows greater-than-normal amounts of blood to return to the hea. In severe anemia, the viscosity of blood 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 (decreases peripheral vascular resistance) allowing even greater amounts of blood to return to the hea. Blood is often shunted away from the splanchnic vascular bed in anemia, which can cause gastrointestinal problems. Ref: Mohrman D.E., Heller L.J. (2010). Answers to Study Questions. In D.E. Mohrman, L.J. Heller (Eds), Cardiovascular Physiology, 7e.