Explain the function of collecting tubules.

(N/A) The collecting tubule plays a crucial role in the concentration of urine and the maintenance of homeostasis.
$1$. It allows for the reabsorption of large amounts of $H_{2}O$ to produce concentrated urine.
$2$. It allows the passage of small amounts of urea into the medullary interstitium to maintain the osmolarity of the medullary interstitium.
$3$. It helps in maintaining the $pH$ and ionic balance of the blood by the selective secretion of $H^{+}$ and $K^{+}$ ions.