Question : Comment upon the hormonal regulation of selective reabsorpt

1.	Question : Comment upon the hormonal regulation of selective reabsorption.
Answer» SOLUTION :Selective reabsorption INVOLVES transport of useful materials like large amount of water, whole of glucose and amino acids, most of `Na^(+)` and `Cl^(-)`, some urea, etc. from glomerular filtrate into blood capillaries. It is regulated by a number of HORMONES e.g. (i) Role of RAAS:Refer Answer no. 2-NCERT Exemplar Problems Solved. (ii) Role of ANF : Atrial Natriuretic Factor is secreted by smooth muscles of atria of heart in RESPONSE to increased blood volume and blood pressure. ANF inhibits the release of renin from juxtaglomerular cells so is antagonistic to RAAS. (iii) Role of ADH:Increased blood volume and decreased osmotic pressure of blood due to excess of water in body fluids inhibits the release of ADH from posterior lobe of pituitary. Low ADH level in blood lowers the permeability of wall of DCT and collecting tubules. So water reabsorption is reduced and urine output is increased to maintain blood volume and osmotic pressure of blood.

Question : Comment upon the hormonal regulation of selective reabsorption.