Brainstem part 2

Question 1

what are the signs of damage of the midbrain

Answer 1

• eye deviates down and out
• loss of pupillary accommodation refflex
• diplopia, lateral deviation of the eye

Question 2

what does the midbrain do

Answer 2

• visual and auditory reflex centres
• CN III IV, nuclei
• subcortical motor centres - red nuclei and substantial nigra
• reticular formation functions

Question 3

what is the visual centre

Answer 3

superior colliculi

Question 4

what is the auditory centre

Answer 4

inferior colliculi

Question 5

what does the red nuclei do

Answer 5

facilitate flexors of arms mainly

Question 6

describe reticular formation functions

Answer 6

arousal
mood and drive (ventral tegmental area)
also periaqueductal grey is important in autonomic control and response to stressors (including descending inhibition of pain)

Question 7

what is the midbrain made out of

Answer 7

• corticospinal tract
• medial leminiscus
• reticular formation
• spinothalamic tract

Question 8

what are the signs of damage of the pons

Answer 8

• facial anaesthesia
• weakens of mastication
• medial eye deviation
• paralysis of facial nerve mscules
• lost of taste
• dry mouth
• vertigo
• loss of hearing

Question 9

what is the function of the pons

Answer 9

• 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

Question 10

what is in the pons

Answer 10

• corticospinal and corticopotine tracts
• reticular formation
• medial leminiscus
• spinothalamic tract

Question 11

what are the symptoms if you have damage to the medulla

Answer 11

• 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,

Question 12

what is the function of the medulla

Answer 12

• 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

Question 13

what two parts of the medulla are there

Answer 13

rostral and caudal

Question 14

what does the rostral medulla contain

Answer 14

• spinal nucleus V
• dorsal motor nucleus
• hyperglossal nucleus
• NTS
• nucleus ambiguous

Question 15

what does the caudal medulla contain

Answer 15

• corticospinal tract
• medial leminsicus
• reticular formation
• spinothalamic tract

Question 16

what is the medial blood supply to the medulla, pons and midbrain

Answer 16

medulla - vertebral arteries and spinal branches

pons/midbrain - basilar arteries

Question 17

what is the lateral bloody supply to the rostral medulla, pons, midbrain

Answer 17

Rostral medulla - PICA
pons - AICA
Midbrain - SCA
- posterior cerebral also supplies lateral aspects of the midbrain

Question 18

what does damage to the brainstem result in

Answer 18

Damage to the brainstem results in whole body sensorimotor dysfunction accompanied by abnormalities in cranial nerve function.

Question 19

how can brainstem disorders be simplified into two questions

Answer 19

Is it LATERAL or MEDIAL?

What is the LEVEL of the LESION?

Question 20

what are the common unilateral medial lesions

Answer 20

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

Question 21

what are the common symptoms of unilateral lesions in the brain

Answer 21

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

Question 22

what can cause a raise in intracranial pressure

Answer 22

1. Haemorrhage
2. Tumour
3. Swelling of brain
4. Berry Aneurysm

Question 23

what are the symptoms of raised intracranial pressure

Answer 23

• headache
• nausea
• vomitting
• bouts of unconsciousness due to pressure on the brainstem

Question 24

what are the types of brain tissue herniation

Answer 24

Subfalcine
Uncal
Tonsillar