how is an involuntary action executed? explain the whole process in detail.

Asked by sakshi.eashan | 27th Sep, 2008, 05:38: PM

Expert Answer:

Involuntary muscles such as the heart or smooth muscles in the gut and vascular system contract as a result of non-conscious brain activity or stimuli endogenous to the muscle itself. Involuntary actions are regulated by autonomic nervous system. The autonomic part of the peripheral nervous system ensures that all our internal organs and glands function smoothly. The autonomic nervous system has two parts: the sympathetic and the parasympathetic. Both supply essentially the same organs but cause opposite effects.

The involuntary nervous system i.e. autonomic nervous system works automatically and without voluntary input. Its parts include receptors within viscera (internal organs), the afferent nerves that relay the information to the CNS, and the efferent nerves that relay the action back to the effectors. The effectors in this system are smooth muscle, cardiac muscle and glands, all structures that function without conscious control. An example of autonomic control is movement of food through the digestive tract during sleep.

The peripheral section consists of nonmedullated nerve fibers that leave the central nervous system in the craniosacral outflow (parasympathetic system) or the thoracolumbar outflow (sympathetic) system, and terminate in effector organs after passing through a ganglion, visible paravertebral ganglia in the sympathetic system, or ganglia embedded in the wall of the target organ in the parasympathetic system.

Answered by  | 27th Sep, 2008, 06:05: PM

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