Question

Release of renin probably depends upon

• A. Glomerular filtration rate
• B. Sympathetic nerve activity
• C. Parasympathetic nerve activity
• D. Both A and B

Answer 1

The correct option is C Parasympathetic nerve activity

The kidneys have built-in mechanisms for the regulation of glomerular filtration rate. One such efficient mechanism is carried out by juxtaglomerular apparatus (JGA). JGA is a special sensitive region formed by cellular modifications in the distal convoluted tubule and the afferent arteriole at the location of their contact. A fall in glomerular filtration rate (GFR) can activate the JG cells to release renin which can stimulate the glomerular blood flow and thereby the GFR back to normal. During a stressful situation, sympathetic nerve stimulation leads to dilation of blood vessels going to the brain, muscles, and heart, whereas those to the skin and kidneys are constricted. The increase in sympathetic activity is responsible for an increase in renal afferent arteriolar constriction, leading to an increase in renin secretion and, ultimately, an increase in aldosterone secretion.