Question

The maximum amount of electrolytes and water (70-80 percent) from the glomerular filtrate is reabsorbed in which part of the nephron?
(a)Ascending limb of the loop of Henle
(b)Distal convoluted tubule
(c)Proximal Convoluted tubule
(d)Descending limb of the loop of Henle

Answer 1

Hint: It is also known as pars convoluta is divide into two segments i.e. $S_1$ and $S_2$. Its function is to reabsorbs filtered glucose into the peritubular capillaries. It drains out filtrate away from a renal corpuscle.

Complete answer:
 The proximal tubule regulates the pH of the filtrate by exchanging hydrogen ions for bicarbonate ions. The proximal tubule is also responsible for secreting organic acid such as creatinine and other bases into the filtrate. Initially, water is absorbed by the epithelial cells lining the tubule with absorption in the interstitial fluid and then into the plasma of the peritubular capillaries. The tubule is divided into five parts based on its anatomy and function- proximal tubule, proximal convoluted tubule, the loop of Henle, connecting tubule, collecting ducts.

Additional Information:
-The mesangial cells are present in the capillaries of the glomerular tuft function as s filtration unit and make up the renal corpuscle.
-The proximal tubule has the characteristic appearance of a luminal brush border formed by the densely packed microvilli which helps in increasing the surface area for the absorptive function. Thus, result in the maximum amount of electrolyte and water reabsorption in the proximal convoluted tubule.
-The cytoplasm of proximal tubules has a high number of densely packed mitochondria for the supply of energy used for the active transport of sodium ions for concentration gradient giving rise to acidophilic appearance.
-The peritubular capillaries that run between the descending and ascending of the tubule.
So, the correct answer is, ‘proximal convoluted tubule.

Note:
 -Human has 1 to 1.5 million nephrons in each kidney.
-The exchange of water and other substances is necessary to regulate the volume of body fluid.
-The glomerular tuft is found in the bowman’s space present in the Bowman’s capsule.
-Blood is filtered by passing through three layers- endothelial cells, basement membrane, and podocyte lining of the capsule.