In an insect, a long nerve cord is present which runs along the whole body. Like hydra, insects also do not have a brain. Instead of brain, many ganglia are present at intervals on the nerve cords.
A ganglia is a mass of nerve cells. The largest ganglion is present in head of an insect. The ganglia receive messages from the sense organs and direct them to other parts of the body through nerves which are attached to ganglia.
Test Your Understanding and Answer These Questions:
- Explain nervous system of hydra by drawing a neat and clean diagram.