Tube feet

Tube feet are small active tubular projections on the oral face of an echinoderm, whether it be a starfish, sea urchin, or sea cucumber. They are part of the water vascular system.

Structure and Function

Tube feet function in locomotion and feeding, they are the primary means of locomotion for the sea urchin and the starfish. The tube feet are filled with seawater, which the echinoderm brings in through its madreporite, a sort of sieve plate. This water is then circulated throughout the body and is used to inflate and deflate the tube feet. When a tube foot deflates, it contracts and bends to create a sort of walking motion. In addition to this, the tube feet also function in feeding by carrying food particles along the ambulacral grooves to the mouth.

Anatomy

The structure of the tube foot has two main parts: the disc and the stem. The disc is the end part that is used for walking and for attaching to surfaces. The stem is the long, hollow part that is connected to the radial canal of the water vascular system. The tube foot has a layer of muscle running longitudinally along the tube foot, and when this muscle contracts, it causes the tube foot to become shorter and wider.

See also

• Echinoderm
• Starfish
• Sea urchin
• Sea cucumber
• Water vascular system
• Madreporite
• Ambulacral groove

Tube feet Resources
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