How the Sleep-Walking occurs in human

A sleep-walker walks or performs other actions during sleep.Sleep-walking is otherwise known as 'Somnambulism'. Some people have a peculiar habit of getting up from bed at night, changing clothes and going out for a walk.And while doing all these things they still remain in the state of sleep.They are not conscious of what they do in that state.
 To know why this happens,we must stand what sleep is.According to the established scientific facts,there is a complex region in our brain which is known as "sleep centre".This centre controls the activities like sleeping and walking.It is regulated by calcium in our blood.During the day when we are awake and most of the parts of our body are functioning, lactic acid, calcium and other substances are produced in the body and get mixed in the blood.Ad later when calcium is carried by the blood to the sleep centre, it becomes active and brings the man to sleep.

The functions of the sleep centre
The sleep centre has two functions in the body.First, it blocks a part of the brain and so we do not feel like doing anything.We might call this "brain sleep".Secondly, it blocks certain nerves in the brain and hence the inner organs and our limbs become inactive and we fall asleep.
 But in some cases, brain goes to sleep and the body remains awake.This might happens to a person whose nervous system does not function normally.A person afflicted by such disorder would get up from bed and walk about.In this situation the brain is in a state of sleep while the body is awake.This happens because of the lack of coordination between the brain and the body.