Which functions of the body are controlled by the brain stem?

The brainstem serves as the body's automatic control center, regulating essential involuntary functions necessary for life. Its primary roles include:12

• Vital Autonomic Functions: It regulates breathing, heart rate, and blood pressure through its respiratory and vasomotor centers.132
• Consciousness and Alertness: It houses the ascending reticular activating system, which is crucial for maintaining alertness and the capacity for consciousness.34
• Communication Pathway: It acts as the main relay station, routing motor outputs from the cerebral hemispheres and sensory inputs to the brain.132
• Cranial Nerve Control: It contains the nuclei for most cranial nerves, which control movement and sensation in the face, tongue, throat, and larynx, enabling functions such as swallowing, speaking, chewing, and facial expression.12

Because the brainstem is densely packed with these critical structures, even small injuries can have devastating effects, such as coma or respiratory failure. Consequently, the complete loss of brainstem function is often considered equivalent to brain death.32