GENERAL HISTOLOGY

Detailed explanation-1: -A closed clam is almost impossible to open, but a hungry sea star can do it. It crawls onto the clam shell and attaches itself, using its hundreds of tiny, tube-shaped feet that work like suction cups. And then it pulls. A sea star can pull for hours, even for days.

Detailed explanation-2: -It is these suction-bottomed tubes that the sea star uses to move about. It draws in water and channels it to canals that run throughout its body, usually ending in the tube feet. By changing the pressure of water in its body, the sea star can move the tubed feet, and thus move forward.

Detailed explanation-3: -The starfish forces open the shell with suction disks on the underside of its body, and then inserts its stomach membranes through its mouth into the opening of the shell. Digestive juices break down the shellfish’s body, which is then absorbed into the starfish’s stomach.

Detailed explanation-4: -But even if the oyster allowed itself to be taken by surprise, as soon as ever it felt the stomach of the starfish on its soft parts, it would immediately close the shell, and the starfish would generally only be able to escape by tearing oft’ its stomach.

Detailed explanation-5: -On the undersides of the arms are hundreds, sometimes thousands, of tiny tube feet called podia. The long slender tube feet are hollow and full of water, like miniature water balloons. Each tube foot is connected to its own tiny sac called an ampulla, that sits inside the body of the starfish.