The water vascular system is a hydraulic system used by echinoderms, such as sea stars and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.
The exact structure of the system varies somewhat between the six classes of echinoderm.
Read more about Water Vascular System: Sea Stars, Ophiuroids, Sea Urchins, Crinoids, Sea Cucumbers
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