Brain Stem Function

Study of the gray matter is indeed a gray area, despite the stupendous progress of medical science. This article provides some information about the function of the brain stem, in a simple and comprehensive manner.
The brain is an extremely vital and sensitive organ. The study of the nervous system and the different areas of the brain and their functions come under the purview of neurology. The entire brain is composed of many different brain parts and functions. The brain stem is a part of the brain and the spinal cord - it is the lowermost part of the brain and the uppermost part of the spinal cord. It is located on the lower posterior part of the brain and is adjoined with the spinal cord in such a way that it is often considered a continuation of the spinal cord. In a way, the brain stem connects the brain and the spinal cord together. The entire brain stem is made up of the hind brain and the mid brain. The chief brain stem function pertains to the supply of motor and sensory cranial nerves to the face and neck. Here is the basic structure of the brain stem, before we proceed to its functions.

Brain Stem Anatomy

As discussed above, it consists of the hind brain and the mid brain. The hind brain contains the medulla, pons, and the reticular formation. The medulla is responsible for regulating various vital autonomic processes such as respiration, blood pressure, heart rate, etc. It is located right on top of the spinal cord. The pons acts as a connector to join the medulla and the cerebellum together and it's function is to coordinate motion on the left as well as the right side of the body. Motor control is an important cerebellum function. The reticular formation is a network of nerves and its function is to regulate attention and consciousness by controlling alertness and sleep. The hind brain composes the lower part of the brain stem.

The mid brain consists of three parts - the tectum, the tegmentum, and paired cerebral peduncles. The tectum is responsible for regulating the senses of vision and hearing. The tegmentum is the container of several tracts, reticular formation, and nuclei. The paired cerebral peduncles transmit axons pertaining to upper motor neurons. Certain parts of the mid brain, known as red nucleus and substantia nigra, are responsible for regulating body movements. The substantia nigra houses a great number of neurons that produce dopamine, and degeneration of these very neurons is strongly believed to have associations with Parkinson's disease. The mid brain composes the upper part of the brain stem.

As we can see that the most prominent function is to control and regulate the motor and sensory processes of the body, a brain stem injury or disorder often manifest as any of the following symptoms:-
  • Dysphagia
  • Sleep apnea
  • Insomnia
  • Speech disorders
  • Difficulty in breathing
  • Distorted balance and coordination of limbs
  • Vertigo
  • Unconsciousness
  • Amnesia
  • Paralysis
  • Vegetative state

The functions of the brain stem are very significant. It is responsible for, and regulatory of, the following functions of the human body:
  • Alertness
  • Attention
  • Arousal
  • Breathing
  • Heart rate
  • Blood pressure
  • Conveys information and signals shared between the peripheral nerves and spinal cord to the upper brain
  • Other autonomic functions such as digestion, salivation, perspiration, dilation or contraction of the pupils, urination, etc.
Among these, the lower brain stem function pertains to regulation of the vital autonomic functions whereas the function of the upper brain stem pertains to regulation of the senses of vision and hearing along with alertness, consciousness, and sleep.

Since this part is connected to both the compound brain as well as the spinal cord, a brain injury that affects the brain stem often has very grave consequences.
Blood pressure
man breathing in the fresh air
Paralysis man
Man with vertigo
Human brain