GENERAL HISTOLOGY

Detailed explanation-1: -One is the oral surface, where the mouth is and the tube feet project. The tube feet on the oral surface are limited to distinct regions called the ambulacral regions. The other surface is the aboral, which typically contains the anal opening of the digestive system.

Detailed explanation-2: -In most echinoderms there is a relatively straightforward digestive process with food entering the mouth and vacating via the anus. Brittle stars and certain groups of sea stars lack an anus, however, and vent food via the mouth once their digestion is complete.

Detailed explanation-3: -Echinoderms have a simple digestive system with a mouth, stomachs, intestineand anus. In many, the mouth is on the underside and the anus on the top surface of the animal.

Detailed explanation-4: -Echinodermata Digestive System Variations Brittle stars have a blind gut, meaning they have no intestinal tract or anus. The lack of an anus means food and waste enter and leave through the mouth.