Brainstem + Tracts

Question 1

what makes up the brainstem

Answer 1

(1.) Midbrain, Pons, Medulla

Question 2

What is the AREA POSTREMA?

Answer 2

(1. ) Lateral to the obex
(2. ) There is no BBB here
(3. ) This is the chemoreceptive trigger zone -> N+V

Question 3

Describe structures you’d seen on the dorsal aspect of the brainstem (with PONS removed).

Hint: think about structures in midbrain, pons, medulla

Answer 3

(1. ) Midbrain: Pineal gland and colliculis
(2. ) Pons: Rhomboid fossa comprising the floor of IV ventricle, obex and area postrema
(3. ) Medulla: Cuneate and gracile tubercle

Question 4

What is the dorsal column sensory pathway responsible for

Answer 4

(1. ) Sensory ascending tracts

(2. ) Important for fine touch, 2 point discrimination, vibration, propreception

Question 5

Describe the dorsal column sensory pathway

Answer 5

(1. ) Info from limbs (1st ON)
(2. ) Dorsal Column Nuclei
- Gracile = lower limb
- Cutaneate = upper limb
(3. ) Decussate in medulla (2nd ON)
(4. ) Thalamus -> internal capsule -> sensory cortex (3rd ON)

Question 6

Describe where would you see sensory loss with lesions in (a.) SC and (b.) Cortex

Answer 6

(1. ) Lesions in SC will show ipsilateral sensory loss

(2. ) Lesions above decussation i.e. brain will show contralateral sensory loss

Question 7

What is the corticospinal tract responsible for

Answer 7

(1.) Descending motor tracts involved in voluntary motor movement

Question 8

Describe the corticospinal pathway

Answer 8

(1. ) Info from motor cortex
(2. ) Pyramid receive info about lower limb, olives receives info about upper limb
(3. ) 80% of UMN fibres decussates in medulla - these are the lateral CST
(4. ) UMN synapses in SC and then leave via ventral horn to limb (LMN)

Question 9

What is bell palsy

Answer 9

(1. ) Unilateral inflammation of CN7
(2. ) Paralysis of facial muscles
(3. ) Failure to close eyes + absent corneal reflex
(4. ) Pain behind ear + hyperacusis
(5. ) Loss of taste to anterior 2/3 of tongue
(6. ) If caused by HZV (shingles): rash is seen on ear and oropharynx

Question 10

What is bulbar palsy and name 6 signs

Answer 10

(1. ) Impaired function of medulla CN (9-12)
(2. ) Due to MND, GBS, tumours or strokes. MS displays pseudobulbar palsy
(3. ) Dysphagia
(4. ) Slurred speech
(5. ) Excessive saliva, dribbling
(6. ) Dysphonia
(7. ) Wasting of tongue
(8. ) Absent gag reflex

Question 11

What is central pontine myelinolysis

Answer 11

(1. ) Occurs when Na levels are corrected too quickly in hypoatremia
(2. ) Destruction of myelin in PONS
(3. ) Causes confusion, balance problems, dysphagia, hallucinations, tremor, weakness in face of limbs

Question 12

Describe locations of the cranial nerves

Answer 12

(1. ) Forebrain = 1, 2
(2. ) Midbrain = 3, 4
(3. ) Pons = 5, 6, 7, 8
(4. ) Medulla = 9, 10, 11, 12 (9,10 are found on ventrolateral sulcus. 11, 12 are found more medially)