Brainstem part 2 Flashcards
what are the signs of damage of the midbrain
- eye deviates down and out
- loss of pupillary accommodation refflex
- diplopia, lateral deviation of the eye
what does the midbrain do
- visual and auditory reflex centres
- CN III IV, nuclei
- subcortical motor centres - red nuclei and substantial nigra
- reticular formation functions
what is the visual centre
superior colliculi
what is the auditory centre
inferior colliculi
what does the red nuclei do
facilitate flexors of arms mainly
describe reticular formation functions
arousal
mood and drive (ventral tegmental area)
also periaqueductal grey is important in autonomic control and response to stressors (including descending inhibition of pain)
what is the midbrain made out of
- corticospinal tract
- medial leminiscus
- reticular formation
- spinothalamic tract
what are the signs of damage of the pons
- facial anaesthesia
- weakens of mastication
- medial eye deviation
- paralysis of facial nerve mscules
- lost of taste
- dry mouth
- vertigo
- loss of hearing
what is the function of the pons
- CN V, VI, VII, VIII nuclei
- Pontine gaze centre with MLF/ mVST spanning brainstem allow conjugate eye and coordinate head movements
- Cerebral relays to the cerebellum (pontine nuclei); vestibulospinal tract- axial muscle adjustment for balance and posture, extensor facilitation
- Micturition centre; pontine respiratory centres act with medullary centres to regulate rate and depth of respiration
- Reticular formation function - sensory filter; arousal; motor –medial reticulospinal tract
what is in the pons
- corticospinal and corticopotine tracts
- reticular formation
- medial leminiscus
- spinothalamic tract
what are the symptoms if you have damage to the medulla
- loss of pain sensation
- vertigo, loss of hearting
- loss of taste
- loss of gag reflex
- dysphagia and hoarseness of voice
- tachycardia
- loss of taste
- loss of cough reflex
- atrophy of tongue muscles,
what is the function of the medulla
- CN IX-XII nuclei (also VIII and spinal n. V)
- Visceral nuclei for control of heart rate, blood vessel diameter, respiration, vomiting, coughing…
- Relay of sensorimotor information to cerebellum via inferior olivary nuclei
- 2nd order neurons of the dorsal column medial lemniscal system & sensory decussation
- Decussation of the pyramids (= motor– corticospinal tract)
- Reticular formation functions… sensory filter; arousal; motor – lateral reticulospinal tract
what two parts of the medulla are there
rostral and caudal
what does the rostral medulla contain
- spinal nucleus V
- dorsal motor nucleus
- hyperglossal nucleus
- NTS
- nucleus ambiguous
what does the caudal medulla contain
- corticospinal tract
- medial leminsicus
- reticular formation
- spinothalamic tract
what is the medial blood supply to the medulla, pons and midbrain
medulla - vertebral arteries and spinal branches
pons/midbrain - basilar arteries
what is the lateral bloody supply to the rostral medulla, pons, midbrain
Rostral medulla - PICA
pons - AICA
Midbrain - SCA
- posterior cerebral also supplies lateral aspects of the midbrain
what does damage to the brainstem result in
Damage to the brainstem results in whole body sensorimotor dysfunction accompanied by abnormalities in cranial nerve function.
how can brainstem disorders be simplified into two questions
Is it LATERAL or MEDIAL?
What is the LEVEL of the LESION?
what are the common unilateral medial lesions
medulla
- Common symptoms + CN XII damage leads to ipsilateral weakness & wasting of the tongue muscles
pons
- Common symptoms + CN VI damage leads to medial deviation of the eye (adduction paralysis)
- Pontine RF (gaze center) leads to ipsilateral gaze paralysis
Midbrain
- Common symptoms + CN III damage leads to ophthalmoplegia
- Red Nucleus damage leads to contralateral cerebellar ataxia
what are the common symptoms of unilateral lesions in the brain
medulla
- Dysarthria, dysphagia, hoarseness, ipsilateral vocal cord paralysis (CN IX, X)
- Ipsilateral loss of gag reflex (CN IX &X)
- Loss of taste sensation (CN IX).
Pons
- Deafness or tinnitis (CN VIII).
- Loss of taste sensation, Complete ipsilateral facial muscle paralysis, can’t shut eyes, impaired salivation/ lacrimation, and hyperacuisis (all CN VII)
- Jaw deviation during opening (Vmo- rostral pons)
midbrain
- Contralateral hemi-anaesthesia (loss of sensation- ascending sensory tracts now are laterally positioned)
- Intention tremor - superior cerebellar peduncle fibres
what can cause a raise in intracranial pressure
- Haemorrhage
- Tumour
- Swelling of brain
- Berry Aneurysm
what are the symptoms of raised intracranial pressure
- headache
- nausea
- vomitting
- bouts of unconsciousness due to pressure on the brainstem
what are the types of brain tissue herniation
Subfalcine
Uncal
Tonsillar
