Question

The substance which is completely reabsorbed from the filtrate in the renal tubule under normal conditions is
A) Urea
B) Salt
C) Glucose
D) Water

Answer 1

The nephron is the kidney's smallest and most functional structural and functional unit. A renal corpuscle and a renal tubule make up this structure. A tuft of capillaries called a glomerulus and a cup-shaped structure called Bowman's capsule make up the renal corpuscle. From the capsule, the renal tubule extends. The capsule and tubule are joined by a lumen and are made up of epithelial cells.

Complete answer:
The tubular fluid filtered via the glomerulus is contained in the renal tubule, which is a long pipe-like structure. The filtrate proceeds to the collecting duct system after passing through the renal tubule. Blood from the efferent arteriole goes into the peritubular capillaries, which surround the loop of Henle and the proximal and distal tubules, carrying everything that wasn't filtered out in the glomerulus. Substances then reabsorb back into the bloodstream from the latter.

Tubular reabsorption of water (obligatory water resorption), nutrients, electrolytes, and tiny proteins such as albumin takes place mostly in the proximal convoluted tubule. Secondary active transport of glucose, amino acids, inorganic phosphate, and a few other solutes occurs by co-transporters driven by the sodium gradient out of the nephron.

Therefore the correct answer is option ‘C’.

Note: In normal circumstances, the renal glomerulus filters up to 180 grammes of glucose every day, with nearly all of it being reabsorbed in the proximal convoluted tubule. Two sodium-dependent glucose cotransporter (SGLT) proteins are involved in this reabsorption. Renal glucose reabsorption is the portion of kidney (renal) physiology that is responsible for retrieving filtered glucose and preventing it from being excreted in the urine. Glycosuria is a condition in which glucose is not reabsorbed by the kidney and instead appears in the urine.