Cockroach,insect surviving without head

It is unbelievable to say that any living being can live without head. How to believe? as the respiratory organ lie within the head and the brain which control the functions of the body is also within the head. Is there any living being that can survive without head?

Cockroach is the only one living being which has being known as the insect which can live without head for long time It is famous for having the capacity of surviving in any difficult situation. Million years ago, due to falling of meteors all the dinosaurs were disappear but the only one living being that is cockroach was able to survive at that time also. But, how is it possible that it can survive without head?

First of all, let's talk about human that how he/she die after his/her head being cut. When the head is cut off from the body there is more flow of blood. This results the decrease in pressure of blood and brings the deficiency in circulation of oxygen. Not only this ,due to deficiency of blood in the body, man ultimately dies. If blood does not come also, due to presence of respiratory organ that is nose is within head , man dies.

But the network of blood vessels is not so complicated as that of developed living being in the body of cockroach . It has open circulatory system due to which blood pressure is low. When the head of the cockroach is cut off blood coming from it immediately freezes as a result there is no chance for the overflow of blood.

For respiration, it does not have the organ like nose as that of human. It has small holes all over the body for respiration process which is called the spiracle and it is not controlled by the brain too.

The spiracles send oxygen directly to the cells through trachea. So that it is not necessary for blood to send oxygen all over the body parts. Cockroach is cold blooded animal so it is not necessary for them to take food frequently. It can survive for 2-3 weeks without any food.
Cockroach as well as other insects have ganglia in different parts of their body due to which body can perform normal activities in absence of brain too. That's why, until it is not attacked by any predators or by the bacterias or viruses attack them cockroach can survive for few weeks without head.