BIO 2135 Lecture Notes - Lecture 10: Ventral Nerve Cord, Aortic Arches, Marine Worm
2 Mar 2017
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Instead of coelom with stuff wrapping around, it happens many times along the animal. Piece that holds the anus on the opposite end is pagidium. Have polarity and bumps and hollows in the chain. Bumps and hollows don"t line up perfectly, it"s a lot weaker. In alpha, it is opposite, they h bond tightly for a strong polymers. Some in the most inhospitable places, sulphur vents. Some are the fancy many tentacle type ones. Usually each has circular and longitudinal muscles, the seta on the sides. Push and pull setae as each coelomic box changes. Nervous system integrates segments for independent function of each coelomic space. When box is at max diameter, setae are pushed into ground to anchor. Setal retractor muscle will push setae in and animal can slide forward. No one ever feeding on sediments on floor yet. In lophophorates, no circulatory system cause they"re small. Coelomic fluid does not mix between the boxes!
