Question

In a healthy individual, GFR is about _____/min, the volume of the filtrate per day is _____, and the amount of micturition per day is
(a) 125mL: 180L, 1.5L
(b) 100mL: 150L, 1.8L
(C) 135mL: 180L, 1.8L
(d) 180mL: 150L, 1.8L

Answer 1

Hint: Urine formation takes place in highly coiled and microscopic structures known as nephrons which are located in the kidneys. Glomerular filtration rate or GFR is a highly regulated process to free the blood from all its nitrogenous wastes while maintaining the solute and water levels in the blood.

Complete answer:
 The amount of filtrate formed per minute in the renal corpuscles of both kidneys is referred to as the glomerular filtration rate or GFR. In a healthy individual, it amounts to 125 mL/min. This means on average, the daily volume of glomerular filtrate per day is 180 liters. But more than 99% of this filtrate is returned to the bloodstream via tubular reabsorption, so only 1.5 liters of urine is excreted on an average by an adult. Micturition is the process of eliminating urine from the urinary bladder via the coordination of detrusor muscles located in the bladder wall.

Additional Information: -The urine is formed in the nephrons which are small, highly coiled tubular structures. It consists of a ‘renal corpuscle’ from where the blood plasma is filtered and a ‘renal tubule’ into which the filtrate enters and passes through.
-A renal corpuscle, in turn, consists of a small cup-like structure bounded by two layers of epithelium known as Glomerular or Bowman’s capsule.
-This capsule surrounds the glomerulus or capillary network which is a labyrinth of fine capillaries. Blood plasma is filtered in the Bowman’s capsule and the filtered fluid then enters the renal tubules of the nephron.
So, the correct answer is ‘125mL: 180L, 1.5L.’

Note: GFR increases when more blood flows into the glomerular capillaries. So, by adjusting the blood flow into and out of the glomerulus or by altering the glomerular capillary surface area available for exchange and filtration, GFR is regulated and maintained. These functions are controlled by three mechanisms namely autoregulation, neural regulation, and hormonal regulation.