2.Why do we sleep?

We feel sleepy when we are tired after work.At night we feel sleepy. Why does one sleep?
It is the rest acquired through sleep that makes us energetic. Sleep is essential to remove
fatigue and to maintain health.
Numerous studies are being done on sleep. the brain controls all the functions of the
body. it has been concluded that the part called cerebellum in the brain controls sleep.
when we work for the whole day,the quantity of of calcium increases our blood. Sleep is
essential to reduce the quantity of calcium. It is the brain which gives the instuction to sleep.
When calcium was directly injected into the brain of animals, they soon fell down
sleeping. But when calcium was injected to blood they did not sleep, Thus, it has been
concluded that it is not only the quantity of calcium but something else is also the cause of
sleep. Research is progressing. Let us wait for the results.