Digestive System of a Purple Sea Urchin
How the Purple Sea Urchin Digests Food
1. The food enters the mouth, which unlike most animals, is located at the bottom of the organism.
2. The food is then mechanically digested by Aristotle's Lantern which is an arrangement of teeth, muscles, and plates.
3. The mouth then opens into the esophagus which runs through and out Aristotle's Lantern.
4. The food continues through the esophagus which widens into the stomach.
5. The siphon, along the inner margin of the stomach, allows water to bypass the stomach.
6. The stomach then loops into the intestine which completes the second loop.
7. The intestine then releases waste into the rectum.
8. The waste is then released out the anus, which unlike most animals, is at the top of the organism.
2. The food is then mechanically digested by Aristotle's Lantern which is an arrangement of teeth, muscles, and plates.
3. The mouth then opens into the esophagus which runs through and out Aristotle's Lantern.
4. The food continues through the esophagus which widens into the stomach.
5. The siphon, along the inner margin of the stomach, allows water to bypass the stomach.
6. The stomach then loops into the intestine which completes the second loop.
7. The intestine then releases waste into the rectum.
8. The waste is then released out the anus, which unlike most animals, is at the top of the organism.
Purple Sea Urchin's Menu
Sources:
http://www.nhm.ac.uk/research-curation/research/projects/echinoid-directory/intro/insides.html
http://www.stanford.edu/~seastar/VirtualUrchin/urchinanatomy.swf
http://library.thinkquest.org/26153/marine/enchino.htm
http://www.stanford.edu/~seastar/VirtualUrchin/urchinanatomy.swf
http://library.thinkquest.org/26153/marine/enchino.htm