Excretory System of Rat

Excretory System

Rat has two reddish-brown kidneys located outside the coelom. Kidneys are sharply bean-shaped; convex on the outer side and concave on the inner side. Each kidney consists of outer cortex and inner medulla.

The kidney consists of a number of uriniferous tubules. Each uriniferous tubule is made up of:

• Bowman’s capsule
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule

The distal convoluted tubules of a number of adjacent nephron open into a common collecting tubule.

Collecting duct are long tubules that traverse through the medulla in the pyramids.

Several adjacent collecting tubules converge to open into a common short and thick duct of Bellini.

All ducts of Bellini open at the tip of the papillae into the pelvis.

Formation of urea takes part in the liver from where it is transported to the kidney.

Urine flows down the ureter and gets collected in the urinary bladder.

When the urinary bladder is filled, it empties by micturition reflex.

Skin, lungs and gastrointestinal tract also play excretory roles by excreting specific wastes from the body.