Discuss how the brain divides its mental functions into subfunctions

The brain is divided into many parts which carry out different functions.  For instance the cerebellum control balance and coordination, the brain stem controls functions such as breathing, blood pressure, digestion, heart rate, etc., There are other motor and cognitive functions that are performed by the brain. The brain typically divide these functions into sub functions for easy handling. 
For instance, to carry out the cognitive process of speaking, the brain typically divides the function into sub functions of talking, perceiving what is been said, thinking about the information received and storing the information for future use [memory]. Different part of the brain handles each of the function, for example, the part of the brain that is responsible for language is the left hemisphere. Different part of the left hemisphere handles different functions; the Broca's area is responsible for speaking while the Wernicke's area is responsible for comprehension of the information that is passed across.