Question

We can produce concentrated/ diluted urine. This is facilitated by a special mechanism. Identify the mechanism.

• A. Counter current mechanism in Henle’s loop/ Vasa recta
• B. Reabsorption/ Secretion in DCT
  
• C. Reabsorption from PCT
  
• D. Reabsorption from Collecting Duct
  

Answer 1

The correct option is A Counter current mechanism in Henle’s loop/ Vasa recta

Production of concentrated/ dilute urine

• The movement of filtrate is in opposite directions in the two limbs of Henle's loop and the vasa recta is called a counter-current mechanism.
• This mechanism helps to maintain a concentration gradient in the medulla.
• This gradient causes the reabsorption of water from the filtrate in various parts of the tubule resulting in the concentration of urine.
• Animals with longer Loop of Henle will be producing more concentrated urine, eg. camel.

Final answer

option (d) Counter current mechanism in Henle’s loop/ Vasa recta