The Nephron: Structural And Functional Unit Of The Kidney

The Nephron: Structural And Functional Unit Of The Kidney

Nephron.
Answer:

Definition:

• Nephron is the structural and functional unit of kidney.

Size and number:

• Total length ranges from 4565 mm.
• Each kidney consists of approximately 1 to 1.3 million nephrons.

Parts:

• Each nephron is formed by.
  1. Renal or malpighian corpuscle.
     • It consists of.
       1. Bowman’s capsule.
          • It is initial dilated part of the nephron.
          • It encloses glomerulus.
       2. Glomerulus.
          • It is formed by the invagination of a tuft of capillaries into the Bowman’s capsule.
          • These capillaries are connected to an afferent arteriole on one end and to an efferent arteriole on the other end.
  2. Tubular portion of nephron.
     • It is the continuation of Bowman’s capsule.
     • It consist of
       1. Proximal convoluted tubule.
          • It is the coiled portion arising from Bowman’s capsule.
          • It is situated in the cortex near the glomerulus
       2. Loop of Henle.
          • It consists of descending limb which arises in continuity with the terminal part of the PCT.
          • Descending limb continues into the thin segment, from this segment arises the thick ascending limb.
       3. Distal convoluted tubule.
          • It is the continuation of thick ascending segment and occupies the cortex of kidney.
          • It opens into the collecting tubule.
       4. Collecting ducts.
          • The collecting ducts passes through the renal cortex and medulla to empty into the pelvis of the kidney at the apices of the medulla.

Types:

• Based on the situation of renal corpuscles, the nephrons are classified into.
  1. Cortical nephrons.
     • Present in the outer cortex of the kidney.
  2. Juxtamedullary nephrons.
     • Corpuscles are present in the inner cortex near medullar/corticomedullary junction.