School of Life Sciences | Ask A Biologist

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Tube Feet

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  • Respiratory: process related to respiration (the action of breathing). The respiratory system is responsible for movement of gases in and out of animals... more

Sea Urchin Tube Feet - Up Close

The tube feet that are not busy pulling the urchin along appear to be engaged in a slow dance. The feet below look a little blurry, because they were moving when the picture was taken. Notice how long and thin they are. Tube feet not only help the urchin move, they also are used to grasp food, and they are part of the respiratory or breathing system.

Sea urchin tube feet

Watch Sea Urchin Tube Feet in Action

The tube feet are part of the urchins water vascular system. They work like a hydraulic system. The urchin contracts its muscles to push water into the tube feet. This extends the feet outwards. When the muscels relax, the feet retract.

 

Sea urchin tube feet in an scanning electron microscope.

This is a scanning electron micrograph, or what is usually called an SEM image, of a sea urchin tube foot. You will notice the suction-cup end. Because the tube foot is retracted (pulled back), there are a large number of folds in the long part of the foot.

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Sea urchin tube feet in an scanning electron microscope.

This is a scanning electron micrograph, or what is usually called an SEM image, of a sea urchin tube foot. You will notice the suction-cup end. Because the tube foot is retracted (pulled back), there are a large number of folds in the long part of the foot.

Share to Google Classroom

Be part of Ask A Biologist

by volunteering, or simply sending us feedback on the site. Scientists, teachers, writers, illustrators, and translators are all important to the program. If you are interested in helping with the website we have a Volunteer page to get the process started.