Well, generally speaking, the cells in our bodies increase in size and then in number initially in response to growth under the supervision of certain chemicals in our bodies which are generated based on the genes we have. The interplay, by design, puts a tight control on cell growth, multiplication and function. The control is so tight that should we get injured, the damaged tissues get repaired to almost exactly the way it was before structurally and sometimes functionally.
These chemicals, some of which are called hormones, shoot up in the body when they are needed and fall back to background levels when their tasks are done. And this regulation keeps things balanced.
When this balance is disrupted, their is a loss of control and, as is typical in nature, something goes wrong. When the cell growth and multiplication and specialisation of function is out of control, the regulatory chemicals are either constantly high and keep stimulating growth unnecessarily, or reassign functions haphazardly.
Now, for normal growth to occur, there have to be three factors in place, viz, the potential for growth, the trigger, and the sustainer. Same with abnormal growth which is due to a loss of regulation. For this loss of regulatory function to occur, there have to be three factors in place. There has to be the potential for loss of control, there has to be a trigger and there has to be a sustainer of this loss of control.
We will consider each factor one after the other.
See part 1 http://wp.me/p6rlMY-Y
Go to part 3 http://wp.me/p6rlMY-13