Brainstem Flashcards
What is the brainstem made up of?
Midbrain
Pons
Medulla
Connects the cerebrum to the spinal cord
What is the function of the brainstem?
Primitive brain
Motor and sensory tracts pass through
Regulation of cardiac and respiratory function.
Regulates the central nervous system
Pivotal in maintaining consciousness and regulating the sleep cycle.
Many basic functions including heart rate, breathing, sleeping, and eating
What is found superior, inferior and posterior to the brainstem?
Superior: thalamus, internal capsule
Inferior: spinal
Posterior: cerebellum
What does the cerebellum do?
Motor control
It receives impulses from the motor cortex
It co-ordinates movements making them precise and controls timing of these movements
Also has roles in attention, language and motor learning
Each lateral lobe of the cerebellum controls motor movement of the body.
But does it control ipsilateral or contralateral movement?
Ipsilateral
What are some causes of a cerebellar lesion?
MS
Tumours + abscesses
Haemorrhage + infarct caused by a clot
Alcohol use
Paraneoplastic syndrome
Clinical features of a cerebellar lesion?
Ataxic gait, they lean to the side of the lesion
Intention tremor
Clumsy, rapid alternating movements
Horizontal nystagmus
Dysarthria: difficulty speaking due to problems controlling the muscles used to speak
What disorders can affect the brainstem?
Tumours
Inflammatory disorders: MS
Metabolic: pontine myelonecrosis
Trauma
Stroke: haemorrhagic or ischaemic
Infection
How do problems with the midbrain manifest?
Midbrain is responsible for
- vision, hearing
- motor control
- sleep/wake
- temperature regulation
So problems with these functions
How do problems with the pons manifest?
Pons is responsible for
- breathing
- communication between different parts of the brain
- hearing, taste, and balance
So problems with these functions
How do problems with the medulla present?
Medulla is responsible for:
- breathing
- heart and blood vessel function
- digestion
- sneezing, and swallowing
- centre for respiration and circulation control
Problems with these function
What is the criteria of brainstem death?
Pupils unresponsive to light
No corneal reflex
No oculovestibular reflex (cold water into ear causing eye movments
No cough or gag reflex
No response to painful stimuli
No respiratory effort despite withdrawal of ventilation for 5 minutes
What is the corneal reflex?
Touch the cornea with a piece of cotton wool
The eye should blink
What is the caloric vestibular reflex?
Put some hot or cold water in the ear
Hot water: eyes should turn towards the contralateral ear with horizontal nystagmus towards the ipsilateral ear
Cold water: eyes should turn towards the ipsilateral ear with horizontal nystagmus towards the contralateral ear
