Brainstem: What to Know

Medically Reviewed by Jabeen Begum, MD on September 01, 2022
5 min read

Your brainstem is the stalk-like part at the base of your brain. It connects the rest of your brain to your spinal cord. You need this tissue in order to perform most bodily functions. In fact, ten of the twelve nerves that originate from your brain are contained within your brainstem. These nerves allow different body parts to: 

  • Move
  • Gather information from your senses
  • Control unconscious functions, like your breathing and heart rate  

A key brainstem function is to convey messages from your brain out to your body and vice versa. This regulates a large number of conscious and unconscious processes. The nerves that pass through your brainstem either continue down to your spinal cord or extend through your head to control facial functions. 

The three main parts of the brainstem are the: 

  • Midbrain
  • Pons
  • Medula oblongata 

The stalk is composed of both white and grey matter. Grey matter contains nerve cell bodies. White matter contains the axons of nerves that connect different bodily structures. Some send information out of your brain to different body parts and others bring back input from your senses. These functions allow your brain to make appropriate decisions. 

Interesting facts about the brainstem: 

  • This structure is the oldest part of your brain. All vertebrates — species with spines — have a brainstem that’s very similar to ours.
  • When people use the phrase “ braindead” they’re usually referring to activity in the brainstem. This is also known as brainstem death. People with this condition need life support to remain alive.  

Your brainstem controls a large number of processes throughout your body. Some of the nerves contained within it produce neurotransmitters, which are used to chemically convey information. These nerves can assist with your: 

  • Balance
  • Reflexes
  • Heartrate
  • Breathing
  • Facial movements
  • Facial sensations
  • Swallowing 
  • Hearing 

Your brainstem is simply one part of your overall brain, though, which is part of your central nervous system (CNS). This system controls nearly all of the large-scale actions that take place within your body and helps coordinate these activities. Of course, a lot of the information that travels throughout your CNS has to pass through the brainstem. 

Your brainstem anatomy contains unique nerve fibers that interact with and support different parts of your body. Each part of the brainstem contains unique cranial nerves. 

The midbrain. This portion of your brainstem has a role in your reward pathways and pain suppression. It also helps coordinate your eye movements. It contains your third and fourth cranial nerves. These are known respectively as your oculomotor and trochlear nerves. Both control motor functions. 

The pons. Some of the neurons in this region make the neurotransmitter norepinephrine. The motor nuclei within this portion help control your movements and breathing. Specifically, the pons contains your fifth, sixth, seventh, and eighth cranial nerves. These are respectively called your trigeminal, abducens, facial, and vestibulocochlear nerves. They contain certain motor and sensory fibers that control your eye movements and facial expressions.  

The medulla oblongata. This portion mostly contains motor fibers that help with movements of various parts of your body, like your tongue. The oblongata contains your ninth, tenth, eleventh, and twelfth cranial nerves. These are respectively called your glossopharyngeal, vagus, accessory, and hypoglossal nerves.

Your brainstem is located at the base of your brain, just above your spinal cord. The midbrain is the highest part of the brainstem. Its top is connected to the diencephalon and the bottom to the pons. The back is connected to the cerebellum. 

The pons is the middle portion of the brainstem. It connects to your midbrain on top and your medulla oblongata on the bottom. 

Your medulla oblongata connects your pons to your spinal cord. Neurons contained within your medulla oblongata extend throughout much of your body, including many of your internal organs. 

Since your brainstem connects much of your body to your brain, problems with this tissue can create widespread issues. You may experience symptoms in just one part of your body, or they could be more widespread. They can also vary greatly depending on the underlying problem.  

General symptoms of brainstem damage include: 

Many different conditions can affect the health of your brainstem. Some serious problems include: 

  • StrokesThese are caused by a disruption in the flow of blood to your brain. Depending on the severity and type, the symptoms can be very widespread and harm many different bodily functions.  
  • Blood clotsThese form when your blood thickens in places that it shouldn’t. They can potentially cut off your blood flow in certain veins and arteries. This can keep blood and fresh oxygen from reaching your brainstem. 
  • TumorsThese are masses of abnormal cells in your brain. Masses in your brainstem are sometimes removed with surgery. These surgeries come with risks of their own, though. 
  • Traumatic brain injuries. These are sudden injuries normally caused by sharp hits or other wounds to your head. Ones to the back of your head are more likely to damage your brainstem. 
  • Heart attacksThese are caused by sudden blockages that prevent oxygen-rich blood from reaching your heart. This can impede blood flow to your brain. 
  • EncephalitisThis is swelling within your brain. It can inhibit certain bodily functions depending on the extent and location of the swelling. 
  • Demyelinating processes. These are diseases that damage or remove the myelin sheath from your neurons. This can prevent information from traveling across your nerves and lead to problems with movement, speech, and most other bodily functions. Multiple sclerosis (MS) is one example of a demyelinating condition.  

You need a healthy brainstem in order to be a fully-functional, conscious person. Fortunately, actions that you take to support your overall brain health can also support your brainstem. For the most part, this involves making positive lifestyle decisions, including: 

  • Eating a balanced diet that’s rich in fruits, vegetables, and lean proteins
  • Exercising regularly
  • Getting a healthy amount of sleep each night
  • Only drinking in moderation
  • Avoiding smoking
  • Working on brain-stimulating puzzles and activities — like crossword puzzles
  • Avoiding or minimizing stress