What is an autonomic nervous system ? It is the second part of a peripheral nervous system. It governs the activity, normally which is not an individual’s control. It must work even when the individual is asleep, and it sustains life processes during anaesthesia and prolonged coma states. The autonomic nervous system deals with survival matters of two kinds; those involving threats to the organism and those involving bodily maintenance.
PARTS OF AUTONOMIC NERVOUS SYSTEM
The autonomic nervous system is made up of two parts:
1.The sympathetic division
2.The parasympathetic division
These two divisions work in opposition to each other to accomplish the survival tasks.
It deals with emergency responding, excited or stressful conditions. It is in control and active when we are feeling emotional, so it involves in states of emotionality. It prepares the organism for vigorous activity. When one part of the sympathetic system is stimulated, other parts are stimulated “in sympathy” with it. (Gullhom and Loofbourrow; 1963). Activation of sympathetic nervous system usually produces increased heart rate, blood pressure, rapid or irregular breathing, dilated pupils, perspiration, dry mouth, increased blood sugar, piloerection (goosebumps), trembling and other changes. The sympathetic division can be regarded as a troubleshooter. When a person faces an emergency or a stressful challenge, it mobilizes the brain for arousal and the body for action. In such situation, digestion stops, blood flows away from internal organs to the muscles, oxygen transfer is increased, heart rate increases and the endocrine system is stimulated to facilitate a variety of motor responses. The sympathetic system tends to act as a unit. During the emotional excitement, it simultaneously speeds up the heart, dilates the arteries of the skeletal muscles and heart, constricts the arteries of the skin and digestive organs and causes perspiration. It also activates certain endocrine glands to secrete hormones that further increase arousal.
It deals with internal monitoring and regulation of a variety of functions. This system typically influences activities related to the protection nourishment and growth of the body. Digestion is one example. The parasympathetic nervous system increases movement of the intestinal system, allowing more nutrients to be extracted from food. It becomes active when we are relaxed and emotionally quite, as relaxing with friends and family. After the danger is over, the parasympathetic division takes charge to decelerate the processes initially activated by sympathetic division, so that individual can relax, calm down and “mellow out”. Digestion resumes, heartbeat slows down, breathing is relaxed and so forth. Basically, the parasympathetic division carries out the body’s non-emergency “housekeeping chores” such as the elimination of bodily wastes, protection of visual system through tears and pupil constriction, and long-term conservation of body energy. It is involved in the maintenance of states of calm and relaxation. It participates in digestion and in general, maintains the functions that conserve and protect the bodily resource. Like the sympathetic system, the parasympathetic division tends to affect one organ at a time. According to American psychologist Walter B. Cannon, the parasympathetic branch handles the vegetative functions of ordinary life; the conservation of bodily resources, reproduction, and the disposal of waste. Actually, these reflect an organism’s operations during times of peace i.e. a lower steady heart rate, peristaltic movements of stomach and intestines, secretion by digestive glands and the like. While the sympathetic and parasympathetic systems are usually antagonistic to one another, there are some exceptions to this principle. For example, the sympathetic system is dominant during trepidation and pleasure, however, a not unusual parasympathetic system during extreme trepidation, in the involuntary release of the bladder and bowl.