GENERAL HISTOLOGY

Detailed explanation-1: -Water enters the madreporite on the aboral side of the echinoderm. From there, it passes into the stone canal, which moves water into the ring canal.

Detailed explanation-2: -Stone canal walls are supported by a series of calcareous rings. Note: Stone canal of starfish takes part in the vascular system. It works as follows-Water enters through the madreporite and flows through the stone canal. It connects to the circular ring canal surrounding the mouth.

Detailed explanation-3: -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-4: -Locomotion: Sea stars move using a water vascular system. Water comes into the system via the madreporite. It is then circulated from the stone canal to the ring canal and into the radial canals. The radial canals carry water to the ampullae and provide suction to the tube feet.

Detailed explanation-5: -This water is taken in through a tiny spot on the upper part of its body, called the madreporite. You can see the madreporite quite clearly on the common sea star, Forbes’ Asterias (photo above). But these tube feet are capable of more than just movement. They also play a role in respiration and in collecting food.