T.S. of Pheretima through the Typhlosolar Region

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COMMENTS:

• Intestine starts after 15th segment. It shows beaded appearence. Section is triploblastic with organ grade of construction and true coelom.

• Intestine is divisible into 3 regions :-

(i) Pre - typhlosolar region (15th to 26th segment).

(ii) Typhlosolar region (from 26th segment to rectum)

 (iii) Post typhlosolar region (rectum). 

Typhlosolar region has median dorsal internal fold.

• Body wall is composed of thin cuticle, columnar epidermis, thin circular muscle layer and thick longitudinal muscle layer, parietal coelomic epithelial layer.

• Intestine is composed of outer visceral coelomic epithelial layer , intermediate longitudinal and circular muscle layer and it's lining is made up of endodermal columnar epithelial ( layer) cells. In typhlosolar region epithelial cells are raised to from typhlosole. 

• Typhlosole is a median internal fold of dorsal wall having chloragogen cells and a capillary blood vessel.

• Typhlosole increase the surface area for absorption.

• Dorsal blood vessel, supra-intestinal excretory duct, ventral blood vessel, nerve cord, sub-neural vessel, blood capillaries and coelom are also seen in section.





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