Anatomy And Functions Of Nervous Of Cockroach

Introduction

The nervous system of cockroaches involves a series of fused ganglia whose arrangement is in a segmental manner. The joining of this ganglia takes place on the ventral side by paired longitudinal connectives. In the thorax region, there are three ganglia, while in the abdomen, there are six ganglia. The nervous system of this insect is such that it spreads throughout its body. A part of the nervous system lies in the head region of a cockroach.  The rest of the nervous system lies along the belly-side or ventral region of the cockroach. 

Central Nervous System in Cockroach

The central nervous system of cockroach involves its brain. Experts also call this as supra-oesophageal ganglion of the cockroach. It involves the following:

•     Supra-oesophageal ganglion (also called brain)
•     Circum oesophageal connectives in the head 
•     Double ventral ganglionated nerve cord.

 The supra-oesophageal ganglia or cerebral ganglion is located in head.  It is formed by the fusion of three pairs of ganglia.

The Central Nervous System of this insect involves the following:

Brain or Supra Oesophageal Ganglion: It is the anterior-most ganglionic mass whose location is above the esophagus. To be more precise, its location is in-between the supporting apodemes, which are in the tentorium region. It has the following components:

1. Protocerebrum: This is the fused ganglia of two segments- Acorn and pre antennal.
2. Deutocerebrum: This is the central part of a cockroach’s brain.
3. Tritocerebrum: This is the posterior part of brain of cockroach. It is  formed by the ganglia of a head’s segment known as intercalary.

Sub-oesophageal Ganglion is an oval-shaped part of the cockroach’s central nervous system. Its location is below the cockroach’s oesophagus region. 

The Ventral Nerve Cord: This part involves a series of ganglia whose location is on the floor of the thorax and abdomen. The ventral nerve cord is present in the head sinus region in cockroaches. 

1. Thoracic ganglia: The first three ganglia are in each thoracic segment. These are referred to as thoracic ganglia by experts.
2. Abdominal Ganglia: Its location is in the abdomen and they are six in number.
3. Connective: These are simply two longitudinal cords in a cockroach. 
4. Commissures: These are the transverse fibres of cockroach’s central nervous system.

Peripheral Nervous System in Cockroach

The peripheral nervous system of cockroaches has nerves that begin from the ganglia of central nervous system and extend to all parts of the body. 

The nerves which originate from the nerve ring and ventral nerve cord supply to all body parts of. This forms the peripheral nervous system of any cockroach. 

A pair of optic and antennary nerves arises from the cockroach’s brain, supplying its antennae and eyes. There are three pairs of nerves that originate from the supraoesophageal ganglion; one pair from the protocerebrum to the compound eyes, one pair from the deutocerebrum to the antennae and one pair from the tritocerebrum to the labrum.

The Visceral or Autonomic Nervous System in Cockroach

The autonomic or visceral  nervous system of cockroaches consists of:

Stomogastric nervous system, Spiracular nervous system and caudal nervous system.  The stomogastric nervous system of cockroaches includes five ganglia which are interconnected to each other. It regulates involuntary activities of foregut. Spiracular nervous system controls the activities of spiracles. Caudal nervous system regulates the activity of the hindgut.

Functions of Nervous System of Cockroach

The nervous system is essential for the survival of the cockroach. Rapid vibrations on the crop’s dorsal surface activation triggers running response occurs in the cockroach’s motor centers of the three thoracic ganglia. The sensory nerves in the hairs send axons  which terminate on the giant interneurons (GI’s) in the abdominal ganlia. 

The nervous system of cockroaches facilitates the quick relaying of the sensory information anterior to the thoracic ganglia. This nervous system enables the cockroach to find an appropriate escape direction when facing a dangerous situation. Two types of escape behavior can be found in the cockroach when excited. These two types of responses are mediate running and the dorsal mediate flying and running.

The supraesophageal and subesopahgeal ganglia modulate the cockroach’s motor activity. The subesophageal ganglion is known to function the initiation of motor programs in the cockroaches. 

Conclusion

The nervous system of cockroaches involves a series of fused ganglia which are  located on the ventral side and are connected by paired longitudinal connectives. Three ganglia are in the cockroach’s thorax, while six are in its abdomen. Its nervous system is spread throughout its body- some in the head and some in the rest. The three parts of the nervous system are-, central, peripheral, and stomatogastric nervous systems of cockroaches. The central nervous system of this insect has three parts- ventral nerve cord, sub-oesophageal ganglion, and supra oesophageal ganglion.