Explain nervous system of cockroach.

Explanation

The nervous system of cockroach consists of a series of fused, segmentally arranged ganglia joined by paired longitudinal connectives on the ventral side. Three ganglia lie in the thorax and six in the abdomen. The upper part of oesophagus possesses brain. It is also known as supra- oesophageal ganglion. It is formed by connection of three ganglia. Two perioesophageal connectives are produced from the brain. They pass from the lateral side of oesophagus and connect to sub-oesophageal ganglion arranged on ventral side of the body and form a nerve ring. The nervous system of cockroach is spread throughout the body. The head holds a bit of nervous system of cockroach while the rest is situated along the ventral part of the body so if head of a cockroach is cutoff it will still live for as long as one week. In the head region, the brain is represented by supra-oesophageal antennae which supplies nerves to antennae and compound eyes.

Sensory organs of cockroach : In cockroach, the sense organs are antennae, eyes, maxillary palps, labial palps, anal cerci etc. The compound eyes are situated at the dorsal surface of the head. Each eye consists of about 2000 hexagonal ommatidia. With the help of several ommatidia, a cockroach can receive several images of an object. This kind of vision is known as mosaic vision with more sensitivity but less resolution, being common during night (hence called nocturnal vision).