Anatomy - Cranial nerves

Question 1

CN I

Answer 1

Olfactory

Question 2

CN II

Answer 2

Optic

Question 3

CN III

Answer 3

Oculomotor

Question 4

CN IV

Answer 4

Trochlear

Question 5

CN V

Answer 5

Trigeminal

Question 6

CN VI

Answer 6

Abducens

Question 7

CN VII

Answer 7

Facial

Question 8

CN VIII

Answer 8

Vestibulocochlear

Question 9

CN IX

Answer 9

Glossopharyngeal

Question 10

CN X

Answer 10

Vagus

Question 11

CN XI

Answer 11

Accessory

Question 12

CN XII

Answer 12

Hypoglossal

Question 13

What functions can cranial nerves have?

Answer 13

sensory (general or special)
motor
parasympathetic

Question 14

Which cranial nerves have motor function?

Answer 14

CN 3, 4, 5, 6, 7, 9, 10, 11, 12

Question 15

Which cranial nerves have sensory function?

Answer 15

CN 1, 2, 5, 7, 8, 9, 10

Question 16

Which cranial nerves have parasympathetic function?

Answer 16

CN 3, 7, 9, 10

Question 17

Do cranial nerves decussate?

Answer 17

generally no
therefore lesions affecting cranial nerves or their respective nuclei will generally present with ipsilateral effects

Question 18

Which cranial nerves decussate?

Answer 18

4 = nerve nuclei contralateral in brain stem

2 = partially decussates

Question 19

What nerve fibres is motor information from the CNS carried in?

Answer 19

efferent nerve fibres

Question 20

What nerve fibres is sensory information from the CNS carried in?

Answer 20

afferent nerve fibres

Question 21

Describe general and special senses

Answer 21

general = pain, pressure, touch, temperature, proprioception

special = all carried in cranial nerves = olfaction, vision, taste, hearing, vestibular function

Question 22

How can cranial nerves be organised and what are the categories?

Answer 22

organised on the basis of the functional components of each nerve

General somatic afferent (GSA) = fibres are related to receptors for pain, temp and touch and proprioceptive receptors in skin, muscles, tendons and joints

General visceral afferent (GVA) = fibres are related to receptors in visceral structures

General visceral efferent (GVE) = fibres are preganglionic autonomic fibres

General somatic efferent (GSE) = fibres innervate skeletal muscle (axons of alpha and gamma motor neurons)

Question 23

Where are cell bodies of first order neurons (preganglionic neurons) located?

Answer 23

brain or brainstem

Question 24

Where are cell bodies of second order neurons (postganglionic neurons) located?

Answer 24

in the periphery in an autonomic ganglion

Question 25

What does the brainstem consist of?

Answer 25

midbrain
pons
medulla oblongata

Question 26

Where does each cranial nerve exit the brainstem?

Answer 26

3+4 = midbrain
5 = pons
6, 7 + 8 = ponto-medullary junction
9, 10, 11 (cranial part) + 12 = medulla oblongata
11 (spinal part) = C1-5

Question 27

Midbrain functions

Answer 27

discrimination of tone and recognition of sound
vision and light reflex
movement of eyes

Question 28

Pons functions

Answer 28

maintenance of awake state
connection between cerebrum and cerebellum
muscle movements of the face
hearing and spatial orientation
sensation from head and neck area

Question 29

Medulla oblongata functions

Answer 29

balance
movement of tongue
sensation from head and neck area