Question

Fall in glomerular filtration rate stimulates the

• A. release of renin
• B. secretion of $H^{+}$
• C. secretion of $K^{+}$
• D. secretion of ammonia

Answer 1

The correct option is A release of renin

The primary step of urine formation is glomerular filtration. The amount of the filtrate formed by both the kidneys per minute is called glomerular filtration rate (GFR). GFR in a healthy human is 125 mL/min. It accounts for 180 litres per day. However there can be scenarios when this GFR falls below 125 mL/min. To avoid this, kidneys have built-in mechanisms for the regulation of glomerular filtration rate. One such mechanism is the release of renin by juxta glomerular apparatus (JGA). JGA is formed by juxta glomerular cells in the distal convoluted tubule and the afferent arteriole. A fall in GFR activates the cells to release renin which stimulates the glomerular blood flow and thereby bring back GFR to normal.