The body of a Jellyfish
Mon, Oct 26th 2009, 10:49
The body of a jellyfish is only 5% solid organic matter â€“ the other 95% is water. The simplicity of these creatures has ensured that they are the longest surviving species on earth.
The body of a jellyfish consists of three parts:
- the bell : the umbrella shaped main body which houses the elementary nervous system. It is perfectly symmetrical which allows the jellyfish to respond to danger in any direction. The jellyfish can also react to light and dark.
- the tentacles : long string like tendrils trailing from the jellyfish body. They contain nerve receptacles which sense and react to external stimuli.
- oral arms : four fatter tentacles which act as the mouth to process prey.
Nerve receptors in the tentacles and oral arm sense the presence of food. When they make contact with prey the tentacles automatically inject venom. The stinging cells of a jellyfish produce venom which produce rashes, and stinging pain which varies in degree between different species.
Jellyfish bodies come in a wonderful variety of colours and brightness, from light blue to deep dark blue, yellow, orange, purple. The body of a crystal jellyfish contains light-producing cells with a light emitting protein that gives them a luminescent glow.