Describe the functional structure of Uriniferous tubule.

Question

Describe the functional structure of the Uriniferous tubule.

Answer 1

Structure of Nephron: 

• It is a unit of excretion in which urine is formed independently. 
• Its an anteriormost part is called a Malpighian body which includes a cup-like Bowmann’s capsule & a glomerulus. 
• The glomerulus is a bunch of blood capillaries. It receives the blood through an afferent arteriole and the blood comes out through the efferent arteriole. The diameter of the afferent is comparatively more.
• The Bowman’s capsule opens into a proximal convoluted tubule (PCT) through a short & straight neck. The anterior part of the PCT is more coiled whereas its posterior part is almost straight. The PCT opens into a Henle’s loop. 
• The Henle’s loop is a U-shaped structure which has a distinct descending limb & an ascending limb. The ascending limb opens into the DCT. 
• The descending convoluted tubule (DCT) is a coiled duct. 
• Many DCT unites to form a collecting duct. The collecting ducts of one pyramid unite to form a duct of Bellini. The ducts of Bellini lead into the pelvis part. 
• The Malpighian body and a part of PCT & DCT are situated in the cortex. Most of the part of PCT & DCT, Henle’s loop and collecting ducts are found in the medulla. 
• The efferent arteriole forms a peri-tubular capillary network around the PCT, DCT & Henle’s loop which is called as Vasa recta. 
• The capillaries of Vasa recta join to form venules which finally open into the renal vein. 

Histology of Nephron: 

• The wall of the Bowman’s capsule is made up of simple squamous epithelium. 
• Its inner wall has special cells, called podocytes. 
• The podocytes have finger-like processes which bind the glomerular-blood capillaries. 
• The neck of the nephron & collecting duct is made up the ciliated epithelium. 
• PCT is made up of simple cuboidal epithelium. It has brushborder of microvilli. 
• The Henle’s loop is made up of simple squamous epithelium. 
• DCT is made up of simple cuboidal epithelium. It is without microvilli.