Name: Excretion in Human Beings
Uploaded: 2019-07-19
Duration: 2 min 52 s
Description: Kidneys eliminate the toxic nitrogenous wastes generated in the body as a result of metabolism. The liver, too, plays a crucial role in this. Take a sneak peek.

Question

With diagram mention the structure and functions of nephron.

Accepted Answer

The anatomical structure of a nephron is composed of a Malpighian corpuscle and renal tubule. The Malpighian corpuscle has two parts, a glomerulus and a Bowman's capsule. The renal tubule has three parts, the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule. These parts can be described as follows:
Malpighian corpuscle: It is a closed knit structure formed by the glomerulus and Bowman's capsule.
i. Glomerulus- The tuft of capillaries of blood vessels invaginating within the double-walled Bowman's capsule is called the glomerulus.
ii. Bowman's capsule- The dilated blind end of the renal tubule, which is made up of a double-walled capsule and surrounds the glomerulus, is called Bowman's capsule.

Renal tubule: The tubular part of the nephron that originates from the tubular pole of the Bowman's capsule and extends up to the collecting tubule is known as the renal tubule.
i. Proximal convoluted tubule- The part of the renal tubule which immediately follows the Bowman's capsule is called the proximal convoluted tubule.
ii. Loop of Henle- The 'U' shaped renal tubule present in the renal medulla in between proximal and distal convoluted tubules is known as the loop of Henle.
iii. Distal convoluted tubule- The thick ascending limb of the loop of Henle is continued into the second set of convoluted tubules in the renal cortex, which is called the distal convoluted tubule.

The functions of the different parts of a nephron are:
Glomerulus- It acts as the filtering organ. The glomerular capillary membranes act as the filtration membrane, which filters out certain substances from the blood to form the glomerular ultrafiltrate.
Bowman's capsule- It forms a part of the filtering membrane through which filtration of plasma takes place. It also acts as a temporary storehouse of the glomerular filtrate.
Proximal convoluted tubule- It is involved in the active reabsorption of glucose, amino acids, sodium, potassium and ADH-independent obligatory reabsorption of water from the glomerular ultrafiltrate.
Loop of Henle- It aids in the formation of concentrated urine from the glomerular ultrafiltrate through the counter-current mechanism.
Distal convoluted tubule- It is involved in the aldosterone-dependent sodium reabsorption and ADH-dependent facultative reabsorption of water from the glomerular ultrafiltrate.

With diagram mention the structure and functions of nephron.

Important Questions on Excretory Products and their Elimination

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