Question: Why does blood pressure fall when a person suddenly
stands from a lying position?
Answer:
Pooling of blood in lower limbs
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↓ Venous return
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↓ Cardiac output
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Transient ↓ BP before Baroreflex correction
Question: Why does heart rate increase when blood pressure falls?
Answer:
↓ BP
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↓ Stretch of carotid sinus & aortic arch
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↓ Baroreceptor firing
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↑ Sympathetic outflow
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Tachycardia & vasoconstriction