Nephron and types of nephron of animals

Nephron and types of nephron of animals

Nephron Components

The glomerular capsule (Bowman’s capsule) is the dilated blind end of the nephron and consists of the invaginated capillary tuft called as the glomerulus. In the mammals the blood from the renal artery is delivered to the afferent arteriole which divides into numerous glomerular capillaries.

Nephron and types of nephron of animals - Nephron Components - Parts of Nephron
Parts of Nephron

The capillaries coalesce to form the efferent arteriole which conducts blood away from the glomerulus and is returned to the systemic circulation through the renal vein.

The glomerular capsule is lined by a layer of epithelial cells.

The area between the glomerular tuft and the Bowman’s capsule is known as the Bowman’s space and it is the site of collection of the glomerular filtrate which is directly funneled into the proximal tubule.

The nephron is continued from the glomerular capsule by proximal tubule which is composed of proximal convoluted portion and the proximal straight portion.

Convoluted portion is within the cortex and the straight portion extends about half way into the outer medulla.

The loop of Henle consist of descending thin limb which is continuous from the proximal straight tubule, the ascending thin limb that terminates at the junction of the inner and outer medulla (cortical nephrons lack a thin ascending limb) and the ascending thick limb that returns to the glomerulus of origin in the cortex and passes between the afferent and efferent arterioles.

The distal nephron begins at this point and consist of distal tubule, the connecting tubule, cortical collecting tubule and collecting duct (outer medullary and inner medullary). The distal tubule, connecting tubule and cortical collecting tubule are collectively referred to as distal convoluted tubule.

Types of nephrons

Mammalian kidney has two principal types of nephrons and are classified based on –Location of their glomeruli and based on Depth of penetration of the loops of Henle into the medulla.

Those nephrons with glomeruli in the outer and middle cortices are called cortical nephrons. They are associated with the loop of Henle that extend to the junction of the cortex and medulla or into the outer zone of the medulla, e.g.,  Marine aquatic mammals.

Those nephrons with glomeruli in the cortex close to the medulla are known as juxtamedullary nephrons. They are associated with loops of Henle that extend more deep into the medulla, e.g.,  mammals in arid region desert animals such as Kangaroo and rat.

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