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Homeostasis I - Coggle Diagram
Homeostasis I
Effect of Posture on CVS
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change of body posture, effect CVS
Aerobic activity
any activity that work large body muscle for at least 20-30 min, elevate cardiac output, accelerate metabolic rate
after several weeks, healthy person increase max cardiac output>>> increase max oxygen delivery to tissue
long term training- skeletal muscle develop more capillary network in response to long term training
Standing immediately
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Compensatory mechanism
mechanism triggered by fall BP, mediated by baroreceptor reflex
vasoconstriction, tachycardia, increase cardiac output
- decrease pressure in carotid and aortic sinus
- decrease rate of discharge from baroreceptor
- decrease the stimulation of nucleus tractus solitarius (NTS)
- decrease vagal activity
- increase sympathetic activity
Prolonged standing
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Compensatory mechanism
- Baroreceptor restore pressure back to normal
- Activation of sympathetic fiber--- lead to release catecholamine from adrenal medulla (increase HR,CO,BP)
- RAA activated
- Angiotensin II cause vasoconstriction, increase BP
- Aldosterone increase reabsorption of sodium and water from kidney--- maintain blood volume and pressure
if person stay stand for longer time--compensatory mechanism may fail and person develop hypotension
Postural hypotension occur in patient with neurophatic problem (diabetes, syphilis)