The brainstem is located below the thalamus and the hypothalamus. The brainstem is about three inches in length and is about as big around as a thumb. The brainstem is divided into the midbrain, the pons, and the medulla.
At the top of the brainstem is the midbrain. The midbrain is the portion of the brain that adjusts the sensitivities of your ears to noises and your eyes to light.
Beneath the midbrain is the pons, a term that means bridge. The pons functions as a conduit between the brain and the spinal cord and is composed mainly of bunches of nerve fibers that connect the cerebral cortex with the cerebellum and the spinal cord. Your pons controls sleeping and dreaming functions.
The medulla is only about an inch long and connects the brain to the spinal cord. It is the medulla that regulates many of the things you do without thought that are critical to your existence, such as heartbeat, breathing, and swallowing. Just think how complicated life would be if every time you had to swallow, you had to focus on the act and will it to happen! The medulla also controls your brain's vomiting center.
Whew! We just covered a tremendous amount of information. Learning about how the human brain is organized is interesting to most people for a simple reason: we all have one. Knowing where in your brain the things you do during the day are directed from adds interest to some of the most mundane things we do.
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