Central Nervous System

The nervous system in cockroach, though not as advanced as the human nervous system, has the three main divisions - the central nervous system, peripheral nervous system and the sympathetic nervous system.

                 

Nervous System of Cockroach

Central Nervous System

The central nervous system consists of two parts

Circum-oesophageal nerve ring

It is entirely situated in the head region. It is ring-like structure around the oesphagus. It consists of the following

Supra-oesophageal ganglion

It is also called the brain or the cerebral ganglion. It is a bilobed structure that is present dorsal to the oesophagus. It carries out the sensory functions.

Circum-oesphageal connective

From the brain, arise two connectives that encircle the oesophagus and ventrally connect to the sub-oesophageal ganglion.

Sub-oesophageal ganglion

It is present ventral to the oesopohagus. From this ganglion arises the nerve cord that passes through the length of the body. It controls the movements of the muscles, mouthparts, wings and legs.

Ventral Nerve cord

It is a solid, double nerve cord that passes along below the alimentary canal till the end of the body. It has nine ganglia along its length. The first three are the thoracic ganglia and the next six are the abdominal ganglia. The thoracic ganglia are big and situated one in each thoracic segment. The abdominal ganglia are present in the 1st, 2^nd, 3^rd, 4^th, 5^th and 7^th segments. Of these the 7^th segment ganglia is the largest.