Brainstem

BRAINSTEM

Brainstem. Your brain and spinal cord are connected by your brainstem. It consists of the medulla oblongata, pons, and midbrain and is located near the base of your brain. To control respiration, heart rate, balance, and other bodily functions, the brainstem communicates with the rest of your body. It helps control essential bodily processes like breathing and heart rate that you don’t have to think about.

BRAINSTEM

Additionally, your brainstem aids with reflexes, balance, and coordination. It consists of three interconnected sections that make up your central nervous system. To assist you move, adapt to your surroundings, and function, each component performs a unique role.

Parts of brainstem

The highest portion is called the midbrain. Among the many tasks performed by the midbrain are processing of vision and hearing as well as motor control, namely eye movements.
Pons: The central part that controls hearing, balance, facial sensations, and eye and face movements.
The lower portion of the brainstem, known as the medulla oblongata, controls blood pressure, respiration, heart rate, and swallowing.
Your reticular activating system is also located in your brainstem. Neurons, which are nerve cells that transmit chemicals and electrical signals throughout the brain, make up the RAS. It collaborates with the thalamus to control your:
Alertness or wakefulness.
Being conscious of your environment.
cycles of sleep and wakefulness.

Brainstem testing

Testing for Reflex and Pupillary Light Reflex
CN II is the afferent nerve, CN III is the efferent nerve, and the Edinger Westphal nucleus in the midbrain is the nucleus that is involved.
In order to test for both direct and consensual reflexes, a bright light is shined into each pupil. When brainstem death occurs, pupillary constriction is absent.

Reflex of the cornea

Brainstem nuclei implicated are the trigeminal and facial nuclei in the pons, CN V1 is the afferent nerve, and CN VII is the efferent nerve. The test measures direct and consensual blinking responses by lightly brushing the cornea with cotton wool. the death is characterized by the lack of blinking.

Vestibular Ocular Reflex

The nuclei involved include the vestibular and abducens nuclei in the pons and the oculomotor nuclei in the midbrain; the efferent nerves are III and VI (to the medial and lateral rectus muscles); and the afferent nerve is CN VIII.

Sensation of Pain

CN V is the afferent nerve, CN VII is the efferent nerve, and the trigeminal and face nuclei in the pons are the nuclei that are involved.

The supra-orbital ridge is subjected to a painful stimulation during the test, and the absence of pain-induced grimacing is the reaction in death.

The Gag Reflex
CN IX is the afferent nerve, CN X is the efferent nerve, and the implicated brainstem nuclei are the spinal nucleus of V and the nucleus ambiguus in the medulla oblongata. Using a spatula to stimulate the pharynx at the base of the tongue or soft palate, the test is conducted. When death occurs, the response is either the pharyngeal contractions and soft plate elevation or the absence of gag.

Summary

The term refers to the irreversible end of all brain activity, including that of the brainstem, which regulates vital life processes including breathing and consciousness. Without artificial help, a person cannot breathe or regain consciousness when the brainstem ceases functioning.