Question

Describe the structure and function of nephron in humans.

Hint:

Nephrons regulate water, electrolytes, and waste removal, maintaining homeostasis.

Answer 1

The nephron is the functional unit of the kidney responsible for filtration, reabsorption, and secretion. Each kidney contains about 1 million nephrons. It consists of two main parts: the renal corpuscle and the renal tubule. 
1. Renal Corpuscle: 
- Glomerulus: A network of capillaries where blood filtration occurs. 
- Bowman’s Capsule: Surrounds the glomerulus and collects the filtered fluid. 
2. Renal Tubule: 
- Proximal Convoluted Tubule (PCT): Reabsorbs water, glucose, and ions like sodium and potassium. 
- Loop of Henle: Concentrates urine by reabsorbing water (descending) and sodium chloride (ascending). 
- Distal Convoluted Tubule (DCT): Further reabsorption of ions and regulation of acid-base balance. 
- Collecting Duct: Final water reabsorption influenced by ADH, and secretion of excess ions. 
Function of the Nephron: 
1. Filtration: Blood is filtered in the glomerulus, and waste products and small molecules pass into the Bowman’s capsule. 
2. Reabsorption: Essential substances like glucose, water, and ions are reabsorbed back into the bloodstream. 
3. Secretion: Additional waste products (e.g., urea, excess ions) are secreted into the renal tubule for elimination. 
The nephron plays a key role in regulating the body’s fluid, electrolyte balance, and eliminating waste via urine formation.