Question

Echinodermata-water vascular system??

Answer 1

The water vascular system of echinoderms is  a system of fluid-filled canals that extend along each of the body regions .( have many external projections called tube feet)

Answer 2

$\text{\underline{\underline{Structure\:of\:water\:vascular\:system:}}}$


⚫The water-vascular system consists of a performed plate called madreporite the pores of which allow the sea water to enter into the system.


⚫From the madreporite starts stone canal which opens into the ring canal.


⚫From each angle of ring canal arises radial canal which runs through the length of each arm.


⚫From radial canal arise lateral canals which end in tube feet. The tube feet are the tube-like appendages. There are two double rows of tube feet in each arm, one double row in relation to each series alternatively placed long and short lateral canals.


⚫Each tube foot can be distinguished into three regions:

(i) A round sac-like ampulla.

(ii) A middle tubular podium.

(iii) A cup-like sucke* at the lower end of podium.


$\text{\underline{Example:}}$ Starfish