The brainstem

The brainstem 

Another part of the brain that is small but powerful is the brainstem that is located below the cerebral cortex and cerebellum ahead. The brainstem connects the rest of the brain to the spinal cord, which covers your neck and back. The brainstem handles all the functions necessary to ensure that your body is alive, such as breathing, digestion of food and blood circulation. 

Part of the role of the brainstem is to control involuntary muscles - those that run automatically, without thinking what. There are involuntary muscles in the heart and stomach, and is the brainstem who tells your heart to pump more blood when you go by bicycle or on your stomach to digest this piece of birthday cake you just eat. (Remember the cortex that controls voluntary muscles. Monitor all the muscles of the body is too big a task for part of the brain!). The brainstem also classifies the millions of messages that the brain and the rest of the body are sent. Uf! It's enough work to be the secretary of the brain!