Alien Body Systems

Lesson 11

Circulation

     Every cell needs oxygen and energy to live, and it needs those all the time. An organism needs an efficient way to distribute oxygen and energy or cells will die. With animals on earth, a heart pumps blood through blood vessels. The blood gets to individual cells through smaller vessels called capillaries. With plants there is also a flow of water up from the roots and food down from the leaves. This is accomplished by using capillary action and pulling the water up as it evaporates. Plants are able to circulate fluids without hearts, but a pump may be essential for organisms that need to be able to move quickly.

snorvep heart and brain    The snorvep's blood is pumped around the body by two pulsing nodes, one just below the hearing organ and one near the back tentacles. You can see the main blood vessel and supporting blood vessels in black in this picture. There are lots of capillaries in the breathing system, and many more in the hearing organ. The tentacles are served by smaller blood vessels. Note that the major blood vessel goes right by the digestive tract so that it can pick up food for the cells. It also goes along the brain so that this organ can be nourished.


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Systems: Digestion, Reproduction, Respiration, Circulation, the Skeletal 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 eviau@earthlink.net