Alien Body Systems

Lesson 11

The Nervous System

The brain and nervous system direct all the actions of the body. Earth animals and people actually have two nervous systems: the autonomic nervous system, which is a sort of autopilot: we are not aware of much that it is doing. The autonomic nervous system receives information about what is going in our blood vessels, our lungs, and our digestive system, and it keeps these parts of the body working whether we are awake or asleep, conscious or unconscious. The other nervous system, the voluntary nervous system, brings us the information and sensations that we are aware of. It conveys our instructions to the body, giving us the power of movement.

snorvep brain     The snorvep has quite a large brain to body ratio. The brain is purple in the picture, and you can see blood vessels leading into, and out of, the brain tissue. Brains need good circulation, because they use a lot of energy. A human brain weighs only about three pounds, but it uses 20%-25% of the oxygen used by the body. It weighs only 2%-3% of our total weight.

     The snorvep's brain weighs almost half a pound, about 3% of it's weight. It lies on the underside of the snorvep, and is not protected by bones. The snorvep's skin is thick and rubbery, especially on the bottom of the body, so the rather flat brain is fairly well protected. However, the movements of the snorvep do tend to bend and flex the brain area. Here again the snorvep uses a mat-type of structure, having the brain constructed of nodules connected by blood vessels and nerve fibers (ganglia). The spaces between the nodules are made of the same sort of spongy tissue that surrounds the cones of the hearing organs. This "packing tissue" protects the brain nodules and absorbs shock and pressure from bodily movement.

     So far as we can tell, the snorvep's brain has separate areas for processing incoming sound and other sensory data. It also has a large area devoted to manipulating the four front tentacles. Another area controls the tongue and its taste buds. We are still studying the snorvep's brain and its interesting but unfamiliar structure.

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Systems: Digestion, Reproduction, Respiration, Circulation, and the Nervous System

© 1999. Elizabeth Anne Viau. All rights reserved. This material may be used by individuals for instructional purposes but not sold. Please inform the author if you use it at