GENERAL HISTOLOGY

Detailed explanation-1: -its outer surface the ring canal gives off a radial water canal into each arm that runs throughout the length of the arm and terminates as the lumen of terminal tentacle. In the arm the radial water canal runs immediately to the oral side of the ambulacral muscles.

Detailed explanation-2: -The radial canal which is across each arm of the sea star has tooth-like structures called ampullae, which surround the radial canal. The aboral surface is also covered with papulae that are involved with the sea star’s respiratory system.

Detailed explanation-3: -From the ring canal water enters 5 radial canals (C3) that extend outward in each of the starfish’s arms or tentacles (A10). 5. Each radial canal has side branches that attach to the numerous tube feet (C7) and ampullae (C6).

Detailed explanation-4: -The radial canals in crinoids run along each arm into an ambulcral groove and tube feet. The ambulacral groove with its many cilia and hydraulically driven tube feet manipulate captured food down the ambulacral grooves along the arms down to the mouth, situated at the tegmen which is positioned at the base of the arms.

Detailed explanation-5: -Five (or a multiple of five) radial canals branch from the ring canal. Radial canals are associated with arms of star-shaped echinoderms. In other echinoderms, they may be associated with the body wall and arch toward the aboral pole. Many lateral canals branch off each radial canal and end at the tube feet.