Nervous System of Cockroach:
The nervous system of cockroach consists of-
- Central Nervous System.
- Peripheral Nervous System.
- Sympathetic Nervous System.
Central Nervous System:
(1) The Brain- The brain of the cockroach is a bilobed supra-oesophageal ganglion situated in front of the oesophagus above the tentorium. Below the oesophagus is a suboesophageal ganglion, formed by the fusion of three pairs of ganglia. A pair of circum-oesophageal connectives connect the two ganglia and form a loop around the oesophagus.
(2) Ventral Nerve Cord- It arises from the sub-oesophageal ganglion. It is formed of two nerve cords lying close together. It has three thoracic ganglia, one in each thoracic segment and six abdominal ganglia five of them in the first five abdominal segments and the sixth is situated in the seventh abdominal segment. Each ganglion is formed by the fusion of two ganglia but the sixth abdominal segment is formed by the fusion of three pairs of ganglia.
Peripheral Nervous System:
The peripheral nervous system includes following nerves arising from the brain and ganglia of ventral nerve cord-
(1) Three pairs of nerves from the brain for eyes, antennae and labrum.
(2) Three pairs of nerves from the suboesophageal ganglia to mandibles, maxillae and labium.
(3) Several pairs of nerves from each thoracic ganglia to limbs and other structures in thoracic segments.
(4) Several pairs of nerves from the first five abdominal ganglia to abdominal parts.
(5) Five pairs of nerves from the last or sixth abdominal ganglion to the last five abdominal segments.
Sympathetic Nervous System:
It consists of one small frontal ganglion in front of the brain, one pair of oesophageal ganglion just behind the brain and a long visceral ganglion. These ganglia are joined by connectives to the brain. Nerve arising from these ganglia supply muscles, alimentary canal and spiracles and control their activities.