
The name autonomous (Gr. autos = self, nomos = governing) indicates that it is a self-governing nervous system. It is a partly independent system. It is not under the voluntary control of nervous system. The activities of some of the organs which are not under the control of the will of an organism are controlled by this system. The autonomous nervous system controls activities like heartbeat, peristalsis in alimentary canal, contraction of urinary bladder, secretion of digestive juices from digestive glands, etc. The autonomous nervous system is also known as "visceral nervous system".
- Sympathetic nervous system and
- Para-sympathetic nervous system.
It consists of a pair of slender longitudinal chains of ganglia, which lie on either side of the dorsal aorta. These chains are called sympathetic nerve chains or cords. They continue forward along the outer sides of systemic arches. Anteriorly, each sympathetic nerve cord enters the skull through jugular foramen and finally ends in vagus or gasserian ganglion. The sympathetic nerve chain is connected with corresponding spinal nerve by a narrow branch called ramus communicans.
Organ & Activities |
Sympathetic control |
Parasympathetic control |
1. Rate of heart beat |
Increases |
Decreases |
2. Stomach a) Tonus and motility b) Secretions |
a) Decrease b) Decrease |
a) Increase b) Increase |
3. Intestine Tonus and motility |
Decrease |
Increase |
4. Bronchial muscles |
Dilate |
Constrict |
5. Blood vessels |
Constrict |
Dialate |
6. Urinary bladder |
Relaxation of muscles occur |
Contraction of the muscles occur |
7. Peristalsis of alimentary canal |
Decreases |
Increases |
8. Secretions of salivary and gastric glands |
Decrease |
Increase |