GENERAL HISTOLOGY

Detailed explanation-1: -The madreporite is an essential part of the circulation system in echinoderms. Through this plate, which is also called a sieve plate, the echinoderm draws in seawater and expels water to fuel its vascular system. The madreporite functions like a trap door through which water can move in and out in a controlled manner.

Detailed explanation-2: -Water enters through the madreporite and flows through a tube, called the stone canal, that connects to the circular ring canal surrounding the mouth. From there, water can flow into five radial canals that branch off the circular ring.

Detailed explanation-3: -The madreporite is a light-colored, calcerous opening used to filter water into the water vascular system of echinoderms. Acting as a pressure-equalizing valve, it is visible as a small red or yellow button-like structure (similar to a small wart) on the aboral surface of the central disk of a sea star.

Detailed explanation-4: -Water enters and leaves the tubes through this sieve-like plate. An echinoderm moves by using many tube feet. Tube feet are small, delicate projections attached along the side of a water-filled tube called a radial canal.