Neurology 3 - Brainstem

Question 1

Define the brainstem

Answer 1

The part of the CNS, exclusive of the cerebellum, that lies between the cerebrum and spinal cord

Question 2

List the major divisions of the brainstem

Answer 2

• Medulla oblongata
• Pons
• Midbrain

Question 3

What is the function of the general somatic afferent in the brainstem?

Answer 3

Sensation from skin and mucous membranes

Question 4

What is the function of the general visceral afferent?

Answer 4

Sensation from GI tract, heart, vessels and lungs

Question 5

What is the function of the general somatic efferent?

Answer 5

Innervates muscles for eye and tongue movements

Question 6

What is the function of the general visceral efferent?

Answer 6

Preganglionic parasympathetic - innervate the gut.ect such as vagus nerve

Question 7

What is the function of the special somatic afferent?

Answer 7

Sensory for vision, hearing and equilibrium

Question 8

What is the function of the special visceral afferent?

Answer 8

Sensory for smell and taste

Question 9

What is the function of the special visceral efferent?

Answer 9

Innervate the muscles involved in chewing, facial expression, swallowing, vocal sounds and turning the head

Question 10

Where is the brainstem?

Answer 10

In the posterior cranial fossa

Question 11

What is not bilateral in the brainstem? What is its function?

Answer 11

• The pineal gland at the roof

- Important for circadian rythms

Question 12

What is the function of the superior colliculus?

Answer 12

• Located below the pineal gland. Contralateral

- Involved in coordinated neck and eye movement

Question 13

What is the function of the inferior colliculus?

Answer 13

• Located below the superior colliculus. Contralateral

- Responsible for auditory reflex

Question 14

What is below the optic chiasm?

Answer 14

The pituitary stalk/infundibulum

Question 15

What is the significance of the pyramidal decussation?

Answer 15

It is the location of cross over of most motor nerves

Question 16

Describe the development of the brainstem with its nerve nuclei

Answer 16

• Motor nerves tend to be medial, sensory tend to be lateral

- Medial to lateral: GSE, GVE, GVA, GSA

Question 17

How can the midbrain be identified on MRI?

Answer 17

• Mickey mouse shape
• Cerebral aqueduct is only in the midbrain
• Cerebral peduncle (forms mickey mouse ears)
• Inferior colliculus
• Substantia nigra

Question 18

How can the pons be identified in MRI?

Answer 18

• 4th ventricle
• Transverse fibres
• Middle cerebellar peduncle

Question 19

How can the medulla be identified in MRI?

Answer 19

Upper
- Pyramids inferiorly
- Inferior olivary nucleus (wavy shape)
- 4th ventricle
Lower
- Medulla has dorsal columns, central canal, and pyramidal decussation

Question 20

Damage to which area causes each symptom of lateral medullary syndrome?

Answer 20

• Vestibular nuclei causes vertigo (loss of balance perception)
• Inferior cerebellar peduncle causes ataxia (change in gait)
• Spinal nucleus (trigeminal) loss of pain and temperature sensation
• Sympathetic tract (horners syndrome)
• Nucleus ambiguus (hoarse)
• Spinothalamic tract (pain and temperature perception from opposite side

Question 21

List the cranial nerves and their class

Answer 21

1 - Olfactory (SVA)
2 - Optic (SSA)
3 - Oculomotor (GSE/GVE)
4- Trochlear (GSE)
5- Trigeminal (SVE/GSA)
6- Abductens (GSE)
7- Facial (GSE/SVE)
8- Vestibulocochlear (SSA)
9- Glossopharyngeal (GVE)
10- Vagus (GVE)
11- Accessory (GSE)
12- Hypoglossal (GSE)

Question 22

Which nerves arise from the midbrain? What are their functions?

Answer 22

• Trochlear nerve comes from the posterior side of the midbrain
• Moves the eye

Question 23

Which nerves arise from the cerebrum, and what are their functions?

Answer 23

• Olfactory nerve and optic nerve
• Olfactory nerve controls sense of smell
• Optic nerve controls sight

Question 24

Which nerves arise from the ponto-midbrain junction? What is its function

Answer 24

• Oculomotor nerve

- Eye movement and pupillary constriction

Question 25

Which nerves arise from the pons? What are their functions?

Answer 25

- Trigeminal nerve | - Sensory and motor to the face

Question 26

Which nerves arise from the ponto-medullary junction? What are their functions?

Answer 26

- Abductens is medial, it controls eye movement - Facial is more lateral, it controls expression and is also sensory (taste) - Vestibulocochlear is the most lateral, it controls hearing and balance

Question 27

Which nerves arise from the medulla oblongata, and what are their funcitons?

Answer 27

- Glossopharyngeal nerve is motor and sensory to the tongue and throat - Vagus nerve is parasympathetic - Accessory nerve is responsible for head, neck and shoulder movement as well as swallowing - Hypoglossal nerve is anterior, it controls speech chewing and swallowing

Question 28

What is the nucleus ambiguus?

Answer 28

- A SVE that helps muscles in the pharynx and laryngopharynx | - Has input and output from many of the cranial nerves

Question 29

What is the edinger westphal nucleus?

Answer 29

- Parasympathetic input to the eye - GVE - Located in the midbrain

Question 30

Where are the salivatory nuclei? What is its function?

Answer 30

- GVE from the glossopharyngeal and facial nerves - Supplies the salivary glands - In the pons and medulla

Question 31

What is the nucleus solitarius? Where is it located?

Answer 31

- Located in the pons and medulla - GVA - Receives taste information

Question 32

Where is the trigeminal nerve?

Answer 32

GSA all through the brainstem

Question 33

What is horners syndrome?

Answer 33

- Loss of sympathetic control - Small pupils - Drooping eye - Lack of sweating around the eye

Question 34

What causes lateral medullary syndrome?

Answer 34

Thrombosis of the vertebral artery or PICA (posterior inferior cerebellar artery)