Question

Give an account of the nervous system in cockroach.

Answer 1

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 nervous system of the cockroach is spread throughout the body. The head holds a bit of nervous system while the rest is situated along the ventral (belly-side) part of its body. So, now you understand that if the head of the cockroach is cut off, it will still live for as long as one week. In the head region, the brain is represented by supra-oesophageal ganglion which supplies nerves to antennae and compound eyes. In cockroach, the sense organs are antennae, eyes, maxillary palps, labial palps, and 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 ommatidia, a cockroach can receive several images of an object. This kind is vision is known as a mosaic vision with more sensitivity but less resolution is common during the night (hence called nocturnal vision).