Question

What are the parts of the nephron and what are the functions in each section?

Answer 1

Answer

The parts of the nephron are :

1) Glomerulus
Function : The capillaries in the glomerulus contains fenestrations. They increase capillary permeability to substances and promote filtration.

2) Bowman's capsule
Function : It is a cup shaped structure that collects glomerular filtrate. The cells of this capsule (podocytes) helps in formation filtration slits at the filtration membrane.

3) Proximal convoluted tubule
Function : This is the site for selective reabsorption of water, NaCl, bicarbonate, glucose, amino acids.
- Substances such as uric acid, antibiotic drugs, creatinine are secreted into the tubule lumen.

4) Loop of Henle
Function : It functions as countercurrent multiplier.

• Descending limb of the loop is permeable to water and impermeable to ions.
• Ascending limb of the loop is permeable to ions and impermeable to water.
• This system helps to promote more water reaborption in order to produce concentrated urine.

5) Distal convoluted tubule
Function : This region is involved in sodium reabsorption upon stimulation by the hormone aldosterone. Calcium is also actively reabsorbed in distal tubule.
- H+, K+ ions are secreted in the tubule lumen.

6) Collecting duct
Function : It is the final region of the nephron.

• When anti-diuretic hormone acts on this segment, aquaporins are inserted in the plasma membrane of its cells to facilitate water reabsorption.
• Urea is also reabsobed in this region.