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Stroke Education
The Brain
Brainstem
Cerebellum
Cerebrum

The Stroke Network
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Brainstem

The brainstem is the stem-like part of the base of the brain that is connected to the spinal cord.

The brainstem controls the flow of messages between the brain and the rest of the body, and it also controls basic body functions such as breathing, swallowing, heart rate, blood pressure, consciousness, and whether one is awake or sleepy.

bullet Brainstem
Midbrain
Pons
Medulla Oblongata

Midbrain

The midbrain, also called the mesencephalon, is a small region of the brain that serves as a relay center for visual, auditory, and motor system information.

It regulates autonomic functions, those that the body carries out without conscious thought, such as digestion, heart rate, and breathing rate.

Pons

A major structure in the upper part of the brainstem is called the pons. The pons has two over-arching roles. The first is the regulation of breathing. In the pons, there is a structure called the pneumotaxic center. It controls the amount of air breathed and breaths per minute, which is known as the breathing rate.

In addition, the pons is involved in the transmission of signals to and from other structures in the brain, such as the cerebrum or the cerebellum. The pons is also involved in sensations such as hearing, taste, and balance. Finally, the pons is also involved in the regulation of deep sleep.

Medulla Oblongata

The medulla oblongata is located in the lower portion of the brainstem. It is very important in things like heart rate and blood pressure. It's responsible for many reflexes in the body, or involuntarily controls, such as vomiting, sneezing, and coughing.
 

A brainstem stroke happens when the brain’s blood supply is interrupted in this area. This type of stroke can result in death, since the damaged brainstem can no longer control the body’s vital functions.


Involuntary Functions

Breathing
Heart Rate
Swallowing
Reflexes to seeing and hearing
bullet Startle Response
Autonomic Nervous System
bullet Sweating
bullet Blood Pressure
bullet  Digestion
bullet Temperature 
Affects level of alertness
Ability to sleep
Vestibular Function
bullet Sense of balance


Observed Problems

 
Decreased vital capacity in breathing, important for speech.
Difficulty with organization/perception of the environment.
Balance
Movement
Dizziness
bullet Vertigo
bullet Nausea
Sleeping difficulties
bullet Insomnia
bullet Sleep apnea

The brain stem contains the fibers which connect the brain to the spinal cord and cerebellum. Strokes within the brain stem may be localized by the pattern of deficits caused by the interruption of these nerves. 

Brainstem strokes are often caused by mechanical obstruction of blood vessels, which might happen during a high speed chiropractic manipulation of the neck, or some other event that causes a very forceful neck movement, such as after a roller coaster ride.  Vertigo (spinning) is a common early symptom of brainstem strokes.

A large stroke in the upper brainstem may sever the connections between the brain and the body. In such an instance, a person may retain consciousness and intelligent thought but become entirely paralyzed except for eye movements. This is called the locked-in syndrome.

Locked-in Syndrome

A condition resulting from interruption of motor pathways in the pons, usually by infarction. This disconnection of the motor cells in the lower brainstem and spinal cord from controlling signals issued by the brain leaves the patient completely paralyzed and mute, but able to receive and understand sensory stimuli to the thalamus.
 

Communication

Communication may be possible by eye gazing (to letters or words on a Communication Board), by code using blinking (once for yes and twice for no), or movements of the eyes (staring at objects, people, etc).

A stroke affecting the brain stem is potentially life threatening since this area of the brain controls functions such as breathing and instructing the heart to beat. Brainstem stroke may also cause double vision, nausea and loss of coordination.  
 

Thalamus

The thalamus is a small structure within the brain located just above the brain stem between the cerebral cortex and the midbrain and has extensive nerve connections to both.

It works to correlate several important processes, including consciousness, sleep, and sensory interpretation.
 

Cranial Nerves

The cranial nerves are composed of twelve pairs of nerves that emanate from the nervous tissue of the brain.

The function of the cranial nerves is for the most part similar to the spinal nerves, the nerves that are associated with the spinal cord.  Apart from sensory functions there are also some that work as motor nerves or mixed nerves.


Stroke Warning Signs

bullet Sudden numbness or weakness of the face, arm or leg, especially on one side of the body   
bullet Sudden confusion, trouble speaking or understanding   
bullet Sudden trouble seeing in one or both eyes   
bullet Sudden trouble walking, dizziness, loss of balance or coordination   
bullet Sudden, severe headache with no known cause



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Original date 3/1/96 Revised 9/24/14