Brainstem

Brainstem
The brainstem consists of the midbrain, pons, and medulla. MedicalRF.com/Getty Images

Brainstem

The brainstem is the region of the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, medulla oblongata, and the pons. Motor and sensory neurons travel through the brainstem allowing for the relay of signals between the brain and the spinal cord. Most cranial nerves are also located in the brainstem.

The brainstem coordinates motor control signals sent from the ​brain to the body.

This brain region also controls life supporting autonomic functions of the peripheral nervous system. The fourth cerebral ventricle is located in the brainstem, posterior to the pons and medulla oblongata. This cerebrospinal fluid-filled ventricle is continuous with the cerebral aqueduct and the central canal of the spinal cord.

Function

The brainstem controls several important functions of the body including:

  • Alertness
  • Arousal
  • Breathing
  • Blood Pressure
  • Digestion
  • Heart Rate
  • Other Autonomic Functions
  • Relays Information Between the Peripheral Nerves and Spinal Cord to the Upper Parts of the Brain

Location

Directionally, the brainstem is located at the juncture of the cerebrum and the spinal column. It is anterior to the cerebellum.

Brainstem Structures

The brainstem is composed of the midbrain and portions of the hindbrain, specifically the pons and medulla. A major function of the midbrain is to connect the forebrain to the hindbrain.

Major structures of the midbrain include the tectum and cerebral peduncle. The tectum is composed of rounded bulges of brain matter that are involved in visual and auditory reflexes. The cerebral peduncle consists of large bundles of nerve fiber tracts that connect the forebrain to the hindbrain.

The hindbrain is composed of two subregions known as the metencephalon and myelencephalon.

The metencephalon is composed of the pons and cerebellum. The pons assists in the control of autonomic functions, as well as states of sleep and arousal. The cerebellum relays information between muscles and the brain. The myelencephalon consists of the medulla oblongata and functions to connect the spinal cord with higher brain regions. The medulla also helps to regulate autonomic functions such as breathing and blood pressure.

Images

More Information

For additional information on the brainstem, see: