Worm Anatomy•
on December 7th, 2009•
Worms eat their food (organic matter which is mixed with the soil) by:
Tunnelling through the soil taking food into their mouth as they go. The prostomium (a fleshy pad) contracts over the mouth.
The food then gets pulled down into the alimentary canal (a tubular passage located between the mouth and the anus.) for digestion and the elimination of wastes.
There are different sections of this tube: buccal cavity, pharynx, esophagus, crop, gizzard and intestine. The buccal cavity – as its name suggests, is a cavity just behind the mouth.
The pharynx – think of this as the suction pump.
The esophagus – a tube leading to the crop and gizzard.
The crop is a storage facility (pouch) for the food.
The gizzard is a thick walled “grinder” that breaks the food down by muscular action and small stones.
The intestine digests the food and extracts the nutrients.
The last step in the process is the excretion of wastes in the form of castings (food and soil which was not digested).
Worm Anatomy•
on December 6th, 2009•
Muscles and the setae are the worms most important anatomy parts for moving. There are muscles that go both circularly around the body and length ways down the body.
To make this really simple; worms move along by extending the anterior (front end), taking hold using their front setae (bristles) then retracting the setae at the prosterior (back end) and pulling their prosterior to their anterior.
Worm Anatomy•
on December 5th, 2009•
Worms have neither a nose nor lungs to breathe through.
Instead worms absorb oxygen through their skin. In order for the oxygen to travel to the worm’s blood stream, the skin must stay moist. The clitellum produces a mucus and air dissolves on the mucus allowing the worms to breathe. If worms dry out, they suffocate.
As fresh air is taken in through the skin, oxygen is drawn into the worm’s circulatory system, and the worm’s hearts pump the oxygenated blood to the head area. The movements of the worm’s body make the blood flow back to the back end of the body, and the hearts pump the blood forward again. Carbon dioxide dissolves out of the blood back to the skin. – Sonya Welter, eHow Editor