Anatomy of Nephron (complete Explaination of Neuron)

NEPHRON;

*Nephron is the structural and functional unit of kidney.
*Each kidney consists of 1 to 1.3 million of nephrons.

Nephron

There are two types of neprons on the basis the situation of renal corpuscle.

1)Corticle Nephron.2)Juxtamedullary Nephron.

1)Corticle Nephron;

*Also called superficial nephron.
*Their renal corpuscles are found in near renal cortex.
*They have short loops of henle.
*About 70 to 80% of nephrons are cortical nephrons.
*Under normal condition of water availability they are responsible for the formation of diluted urine.

2)Juxtamedullary Nephron;

*The renal corpuscles of these nephron are found close to the junction of cortex and medulla.
*About 20 to 30 percent of nephrons are juxtamedullary nephrons.
*They have long loop of henle.
*When water is in short supply  they increase the retention of water in body.

Anatomy of Nephron;

Nephron consists of two main parts.1)Renal Corpuscles(also called malpighian corpuscle)2)Renal Tubules

1)Renal Corpuscles;

Renal corpuscles is situated in the cortex of kidney. Renal corpuscles consists of two portions.
i)Glomerulus
ii)Bownman's Capsule

i)Glomerulus;

*These are the networks of capillaries.
*The capillaries arise from the afferent arteriole.
*The afferent arterioles divides into 3 to 5 capillaries then these capillaries subdivide into many small capillaries. All these small capillaries join and then form efferent arteriole which exit bowman’s capsule.

note; Diameter of efferent arterioles is less than afferent arterioles, due to this diameter difference there is the possibility to filter the blood.

*The vascular system in the glomerulus is arterial.
*The Glomerular capillaries are made up single layer of endothelial cells.
*This endothelial layer has many pores which are called filtration pores(fenestrae).

Bowman’s Capsule:

It is cup-shaped swellings which surround the glomerulus.It is consist of two layers.i)Outer Parietal Layer.Ii)Inner Visceral Layer.
*These two layers are as shown in the figure below.
*Both the layers of Bowman’s capsule are composed of a single layer of flattened epithelial cells. 

Renal Corpuscles

2)Renal Tubules;

Renal tubules of nephron is consist of three parts.
i)Proximal Convoluted Tubule.
ii)Loop of Henle.
iii)Distal Convoluted Tubule.

i)Proximal Convoluted Tubule;

From Bowman’s capsule there arise a coiled tubule called proximal convoluted tubule.
*Proximal convoluted tubule is formed by single layer of cuboidal epithelial cells.
*Length of this tubule is about 14mm and its diameter is about 55micrometer.
*Proximal convoluted tubule continues as loop of Henle.

ii)Loop of Henle;

*From the proximal convoluted tubule there arise a U-shaped structure which is called Loop of Henle.
*Loop of Henle consists of three parts.
a)Descending Limbb
Hairpin Band
c)Ascending Limb
*Total length of Loop of Henle is about 6mm but it is variable in length and its diameter is about 55micrometer.

i)Descending Limb:

*Descending Limb is consisted of two segments;
a)Thick Descending segment.
b)Thin Descending segment.

A)Thick Descending Segment;
*This is the continuation of proximal convoluted tubule.
*It is made up of brush-bordered cuboidal epithelial cell.

B)Thin Descending Segment;
*This is the continuation of thick descending segment.
*It is made up of flatten epithelial cells.
*Thin descending segment continues as hairpin bend of loop of Henle.

ii)Hairpin Band;

*It is made up of flattened epithelial cells.
*Hairpin Band continues as ascending limb.

iii)Ascending Limb;

*Ascending limb is consisted of two segments.
a)Thin Ascending Segment.)
bThick Ascending Segment.

a)Thin Ascending Segment;
*It continuation of Hairpin bend.
*It is made up of flattened epithelial cells.

b)Thick Ascending Segment;
*It is the continuation of thin ascending segment.
*It is made up of cuboidal epithelial cells.

3)Distal Convoluted Tubule;

*After ascending limb the renal tubule again highly coiled called distal convoluted tubule.
*It is the last portion of renal tubules.
*It is lined by single layer of cuboidal epithelial cells(Intercalated cells).
*It continues as collecting duct.

Collecting Duct;

*It is the continuation of distal convoluted duct.
*The distal convoluted tubules of many nephrons open in a single duct called collecting duct.
*The initial part of collecting duct is in cortex while the lower part of collecting duct is in medulla.
*Collecting duct is made up of cuboidal columnar epithelial cells.
*It is formed by two types of epithelial cells.
i)Principal cells(P cells)
ii)Intercalated cells(I cells).

Nephron Anatomy

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