Question

Which of the following statements is incorrect?
A) Mammals have the ability to produce concentrated urine.
B) Counter current is due to the flow of filtrate in two limbs of Henle's loop in the opposite direction.
C) Henle's loop and vasa recta play a significant role in concentrating the urine.
D) Flow the filtrate through vasa recta also follows the counter-current pattern.

Answer 1

Hint:The counter-current mechanism concentrates the urine. This mechanism is observed in the kidneys by the nephrons of the human excretory system.

Complete answer:
Let us analyse each given option to find out the correct answer.
>Option A: Mammals have the ability to produce concentrated urine. Henle’s loop and vasa recta play a significant role in this. The kidney of mammals has the ability of the kidneys to produce concentrated urine for the elimination of waste products while losing a minimum of water. So, this statement is correct. Therefore, this is an incorrect option.
>Option B: The flow of filtrate in the two limbs of Henle’s loop is in opposite directions and thus forms a counter current. The flow of blood through the two limbs of the vasa recta is also in a counter-current pattern. The proximity between the Henle’s loop and vasa recta, as well as the countercurrent in them, help in maintaining an increasing osmolarity towards the inner medullary interstitium. So, this statement is correct. Therefore, this is an incorrect option.
>Option C: Henle's loop and vasa recta play a significant role in concentrating the urine as the flow of filtrate in the two limbs of Henle's loop is in opposite directions and thus forms a counter current. The flow of blood through the two limbs of the vasa recta is also in a countercurrent pattern. So, this statement is correct. Therefore, this is an incorrect option.
>Option D: Filtrate flows through the loop of Henle and not through the vasa recta also follows the counter-current pattern. So, this statement is incorrect. Therefore, this is the correct option.

Hence the correct answer is option ‘A’.

Note:It is to be noted that the human kidneys can produce urine nearly four times concentrated than the initial filtrate formed. The other functions of kidneys are,
>They help in regulating the osmotic pressure of a mammal’s blood via excessive filtration and purification.
>Kidneys filter blood nearly 400 times in a day.
>They help in excretion of waste products, toxins and drugs via the urine.