what's some facts about the digestive, respiratory, and the nervous system?worms digestive, repiratory,nervous system?
Posted by ATP-Man
There are three main groups of worms: Platyhelminthes (flatworms) Nematoda (roundworms) and Annelida (segmented worms). Here are some facts about each group.
Platyhelminthes: They contain rudimentary organ systems such as: a ladder-like nervous system with a small brain and in some cases photosensitive eye spots. A primitive digestive system consisting of a mouth, pharynx and branched gastrovascular cavity. No definite respiratory system with organs.
Nematoda: (Roundworms) Ascaris, pin worms, hookworms, and Trichina
They possess a one way digestive system. Mouth, intestine and anus.
They have a circular brain and several longitudinal nerve cords. No definite respiratory system with organs.
Annelida: The digestive tract is divided into several well developed organs: pharynx, esophagus, crop, gizzard, and intestine.
The brain is small and is located under the pharynx. A ventral nerve cord extends from the brain and runs the length of the body. In each segment it swells to form a structure called a ganglion.
They breathe through their moist skin.
Orignal From: what's some facts about the digestive, respiratory, and the nervous system?
Post a Comment