We can perceive at the brainstem as a special type of bridge that links the cerebrum with the spinal cord. It has a crucial role for the human body, implicitly for the central nervous system, as it controls most of the autonomic functions, as well as it supports motor and sensitive innervation to the facial area and to the neck.
The brainstem has 3 main structures:
- The midbrain. It’s also called the mesencephalon and consists of tectum and the tegmentum. The midbrain controls the eye movement, the pupil dilatation and the moves of the human body, but also the hearing function;
- The medulla oblongata. Located in the inferior part of the brainstem, it controls the most important autonomic functions, such as breathing, the heart beat and the heart rate, but also the blood pressure. Also, the medulla has within the centers for the cardiac functions, for the respiratory system and for the vasomotor function. As well, in the medulla there can also be found the reflex centers for reflexes and actions like vomiting, sneezing, swallowing and coughing;
- Pons. This structure connects the cerebral cortex with the above described structure, the medulla oblongata. Among its numeral roles, in the pons there can be found several cranial nerve nuclei from the trigeminal, the abducens, the facial and the vestibulocochlear nerves. This automatically involves the pons in processes like eye movement, facial mimics, saliva secretion. Besides them, the pons is also implicated in processing the arousal sensation, but also in establishing the sleep patterns (with the hypothalamus, that in turn establishes the circadian rhythm);
Viewed as a whole system, the brainstem plays an important role in conduction. It can be perceived as a two way bridge in which the information sent by the hemispheres or by the body to the cerebellum (and vice versa) is being transferred through the brainstem. As well, it’s important to note that the 10 out of 12 cranial nerves (actually, they are in pairs, but are commonly referred as being one for simplicity) originate from the brainstem. We can therefore say that it’s responsible for innervating the facial area, the head, but also some of the internal organs (especially the 10th pair of cranial nerves, who travel way down to the thoracic cavity).
Last, but not least, an extremely important role of the brainstem is in the autonomic processes. Since it regulates the control “room” of the circulatory and the respiratory systems, but also regulates awareness and the pain sensitivity, maintaining as healthy as possible is vital for the human body. If any kind of damage occurs (due to head trauma or other neurological disorders) in this area, emergency medical help is required, especially if it’s accompanied by symptoms like hearing problems, co-ordination problems, dysphagia and so on.