NEETZoologyExcretory Products and their Elimination
A person meets with a severe accident resulting in significant blood loss. This sudden drop in blood volume and blood pressure will immediately trigger which of the following physiological responses to restore homeostasis?
Options
- AIncreased secretion of Atrial Natriuretic Factor (ANF) from the atria of the heart
- BActivation of JG cells to release renin into the blood
- CSuppression of ADH release by the osmoreceptors in the hypothalamus
- DDecrease in aldosterone secretion from the adrenal cortex
Correct answer
B. Activation of JG cells to release renin into the blood
Step-by-step solution
Severe blood loss causes a significant drop in blood volume, blood pressure, and Glomerular Filtration Rate (GFR). According to NCERT, a fall in GFR or glomerular blood pressure activates the Juxtaglomerular (JG) cells to release renin. Renin converts angiotensinogen in blood to angiotensin I and further to angiotensin II. Angiotensin II is a powerful vasoconstrictor that increases glomerular blood pressure and stimulates the adrenal cortex to release aldosterone, which promotes reabsorption of Na ^+ and water from