explain the sturucture of nephron with diagram

Asked by nil.rudra2001 | 26th Apr, 2016, 02:03: PM

Expert Answer:

  • A kidney is composed of an enormous number of uriniferous tubules. They are also known as nephrons or renal tubules or kidney tubules.
  • Nephrons are the structural and functional units of the kidney.
  • Each kidney is formed of about 1 million nephrons.
  • Nephrons are held together by a connective tissue.

Structure of nephron:

  • Each nephron is made of a glomerulus and a renal tubule.

Glomerulus:

  • It is a tuft of anastomosing blood capillaries formed by the fine branches of the
    afferent arteriole. 
  • These capillaries of the glomerulus again unite to form the efferent arteriole.
  • The afferent arteriole is wider than the efferent arteriole.
  • The afferent arteriole brings blood into the glomerulus, while the efferent arteriole collects blood from the glomerulus.

Renal Tubule:

The renal tubule comprises the following regions:

Bowman’s Capsule

  • The Bowman’s capsule lies in the cortex.
  • It is a thin double-walled, cup-like depression.
  • It is the blind end of the nephron.
  • The glomerulus is located in the concave depression of the Bowman’s capsule.
  • The Bowman’s capsule and the glomerulus together are called Malpighian Capsule or Renal Capsule.
  • The outer layer of the Bowman’s capsule is made of flattened epithelial cells.
  • The inner layer is in close contact with the glomerulus and bears special cells called podocytes.
  • Podocytes have many feet-like processes called pedicels and minute slit-like pores called slit pores.   

Proximal Convoluted Tubule (PCT)

  • PCT lies in the cortex.
  • It is also known as the first convoluted tubule.
  • The Bowman’s capsule continues into the PCT.
  • It is lined with a layer of columnar epithelial cells.
  • The columnar cells are with numerous microvilli to increase the surface area of absorption.   

Loop of Henle

  • It lies in the medulla.
  • It is U-shaped.
  • It is not convoluted.
  • It has a descending limb and an ascending limb.
  • Each limb has a thick region towards the cortex and a thin region towards the medulla.
  • Thick regions are lined with columnar epithelial cells.
  • Thin regions are lined with flat epithelial cells.          

Distal Convoluted Tubule (DCT)

  • It lies in the cortex.
  • Its short terminal part is called a collecting tubule.
  • The collecting tubule opens into the collecting duct.
  • DCT in lined with ciliated columnar epithelial cells.
  • The collecting duct receives the contents of many renal tubules.
  • The collecting duct is a larger duct which receives collecting tubules of several nephrons.
  • Collecting ducts pass into the renal medulla and join with each other to form the ducts of Bellini.
  • The ducts of Bellini run through the renal pyramids and open into calyces.
  • All calyces open into the pelvis.
  • From the pelvis, urine is carried to the urinary bladder through the ureters.

Answered by Sheetal Kolte | 26th Apr, 2016, 06:14: PM