Nervous System
There is not one known echinoderm that contains a brain. (tolweb.org) All echinoderms have radial nerves which are spread throughout their bodies. There is one nerve ring that surrounds the stomach of the organism, and this is what connects the radial nerves(tolweb.org).
A starfish's nervous system, in particular, is actually pretty simple. They do not have a brain, and they also don't have ganglia to coordinate how they move. Starfish have one nerve ring that surrounds the mouth and stomach of the starfish in the center of its body. Branches of radial nerves extend through each of the starfish's arms. On the end of each arm are little eye spots, which detect shadows and changes in the brightness of the light around it(www.mesa.edu).
A starfish's nervous system, in particular, is actually pretty simple. They do not have a brain, and they also don't have ganglia to coordinate how they move. Starfish have one nerve ring that surrounds the mouth and stomach of the starfish in the center of its body. Branches of radial nerves extend through each of the starfish's arms. On the end of each arm are little eye spots, which detect shadows and changes in the brightness of the light around it(www.mesa.edu).