Question

Reabsorption of useful substances from glomerular filtrate occurs in
A) Collecting tube
B) Loop of henle
C) Proximal convoluted tubule
D)Distal convoluted tubule

Answer 1

Hint:Reabsorption is the process by which water and solutes are reabsorbed from the pre-urine into the plasma.

Complete answer:
Before we go ahead, let us first know a little more about excretion in humans. The process by which waste substances are secreted out of the body is known as excretion. The organs which help in excretion are known as excretory organs. The various organs involved are,
>Pair of kidneys
>Urethra
>Urinary bladder
>Pair of ureters

Option A: The function of collecting tubes is absorption of water and transportation of urine. It has no function of reabsorption, therefore, this is the incorrect option.
Option B: Loop of henle reabsorbs electrolytes and sodium chloride from urine and not from glomerular filtrate. Therefore, this is the incorrect option.
Option C: Proximal convoluted tubule is involved in reabsorbing ions, water and nutrients from the glomerular filtrate. It also helps in removing toxins and maintaining the ionic balance. It does it by reabsorbing bicarbonate ions from the filtrate and secreting ammonia, hydrogen and potassium into the filtrate. Therefore, this is the correct option.
Option D: Distal convoluted tubules are involved in reabsorption of water and sodium ions. It has more or less similar functions as PCT. But, it does not reabsorbed from glomerular filtrate itself. Therefore, this is the incorrect option.

Thus, the correct option is (C) Proximal convoluted tubule.

Note:Do not get confused between PCT, loop of henle and DCT as all of them are involved in reabsorption. To make sure that you don't get confused, try picturing the structure of nephrons. The part next to glomerulus, i.e. PCT receives the glomerular filtrate while the other two reabsorb from urine.