Question

Describe in detail how the respiratory, circulatory, and urinary systems would react to a sudden and serious decrease in blood pressure (hypotension) OR a sudden decrease in plasma pH (acidosis) to compensate for the decrease by raising the falling pressure or pH.

Answer 1

Urinary system : When there is sudden drop in blood pressure, or when the blood volume is low, in response to this kidneys release an enzyme known as renin, this enzyme than converts angiotensinogen produced by the liver to the hormone angiotensin-1, an enzyme by name angiotensin converting enzyme (ACE) found in the lungs converts angiotensin-1 into angiotensin-2, which causes blood vessels to constrict which results in increased blood pressure, in addition to this angiotensin-2 stimulates the release of aldosterone hormone from the adrenal gland, which causes renal tubule to retain sodium, and water and than excrete potassium, together angiotensin-2 and aldosterone are responsible for maintaining blood pressure.

Circulatory system : Baroreceptors are mechanoreceptors located in the carotoid sinus and aortic arch, their function is to sense pressure changes by responding to change in tension of the arterial wall. When there is drop in blood pressure, decreased blood pressure is sensed by the baroreceptors as decrease in tension, therfore there will be decrease in firing of impulse, this causes vasomotor center to activate sympathetic activity in heart and blood vessels, this results in increase in heart rate and vasoconstriction which would result in increase in blood pressure to restore normal blood pressure levels.

Respiratory system, when there is decreased level of carbon di oxide in the body, this results in decreased Ph, because CO2 gets converted to carbonic acid, this generation of acid will decrease the ph, in response to this lungs start to increase the rate and depth of breathing, which will drive out CO2 out of the body thus restoring normal pH levels.