Question

Function of loop of Henle is
(A) Conservation of water
(B) Formation of urine.
(C) Filtration of blood
(D) Passage if urine

Answer 1

Loop of Henle is found in the nephrons. Nephrons are found in the kidney which are responsible for filtering the wastes from the body and then these wastes are excreted outside via the excretory system. There are two loops of Henle i.e. ascending loop of Henle and descending loop of Henle.

Complete answer:
Kidney is the main excretory organ in the human body. It is responsible for formation of urine which is excreted outside via ureter, urinary bladder and then it is excreted outside the body via urethra. The urine is produced in the nephrons. In the kidney, millions of nephrons are found.
Nephron consists of following parts:

Renal corpuscles: It is the bowman capsule which encloses the glomerulus. It is responsible for glomerular filtration. Here all components of blood pass through it except the proteins.
Proximal convoluted tubule: It is a coiled network of tubules. It is responsible for secretion of hydrogen and ammonia ions and absorption of glucose and amino acids occurs in this part.
Loop of Henle: It consists of two loops:
Descending loop of Henle: Descending loop of Henle is permeable to water but it is impermeable to electrolytes such as potassium, sodium and chloride ions etc.
Ascending loop of Henle: This loop is permeable to electrolytes but it is impermeable to water.
Distal convoluted tubule: This section is responsible for reabsorption of water and sodium ions. Ammonium ions, hydrogen and potassium ions are secreted.
The reabsorption is found to be minimal in the loop of Henle region. But it has an important role in maintaining the high osmolarity of medullary interstitial fluid.
Loop of Henle and vasa recta are found in the countercurrent mechanism in which they are found in proximity to each other. This mechanism helps in maintaining the concentration gradient in the medullary interstitium. In this case, sodium chloride transported by ascending limb is exchanged with descending limb of vasa recta. In the descending limb of the loop of Henle, water is transported back to the ascending loop of recta. This leads to concentration of urine.

Hence, the answer is: “Conservation of water” or “Option A”.

Note: Counter current mechanism is responsible for concentrating the urine. Loop of Henle and vasa recta are involved in this mechanism. The water transported by descending loop of Henle is exchanged with vasa recta whereas electrolytes transported by ascending loop of Henle are exchanged by descending limb of vasa recta.