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Flashcards in Week 4 Deck (59)
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1

Components of cranial nerves

General sensory axons
Special sensory axons
Motor axons
Autonomic axons

2

What part of the nervous system are the cranial nerves a part of

Peripheral nervous system

3

How do cranial nerves differ from spinal nerves

Arise at irregular intervals from the CNS

4

What's the brainstem

Connects the brain to the spinal cord and has 3 parts:
Midbrain
Pons
Medulla

5

What are cranial nerve nuclei and where are the majority

Collections of cell bodies of nerve fibres which make up the cranial nerves
In the brainstem

6

Describe the route, fibres present and function of the olfactory nerve

Route - cell bodies in olfactory nasal mucosa, pass through foramina in cribriform plate, enter olfactory bulb (in contact with frontal lobe of cerebral hemispheres)
Fibres - special sensory
Function - smell

7

How would you test olfactory nerve function

Smelling salts - one nostril at a time

8

How do the first 2 cranial nerves differ from the rest

Anterior extensions of forebrain

9

What is anosmia and the causes in order of most common

Loss of sense of smell
Causes:
URTI
Head injury that fractures the cribriform plate

10

Describe the route, fibres present and function of the olfactory nerve

Route - passes through the optic canal from the retina and crosses over to form the optic chiasm near the pituitary. It then becomes the optic tract.
Fibres - special sensory
Function - vision

11

How would you test the optic nerve

Visual tests and look at pupils
One eye at a time

12

What can cause lesions of the optic nerve and therefore vision loss

Optic neuritis
Pituitary tumours
Stroke
Carotid aneurysm

13

How can the optic nerve be viewed

Fundoscopy

14

Describe the route, fibres present and function of the oculomotor nerve

Route - arises from midbrain, runs in cavernous sinus, goes through the superior orbital fissure
Fibres - Motor and parasympathetic autonomic
Function - motor innervation to (sup, med, inf) recti, inferior oblique and levator palpebrae superioris; constriction of pupil

15

How can the oculomotor nerve be tested

Eye movements
Inspect eyelids and pupils
Pupillary light reflex

16

What structures are in the cavernous sinus

Internal carotid arteries
Oculomotor nerve
Trochlear nerve
Ophthalmic nerve
Maxillary nerve
Abducent nerve

17

Causes of oculomotor nerve lesions

Raised intracranial pressure
Aneurysms
Cavernous sinus thrombosis - clot in cavernous sinus usually from infection spread from skull/face
Diabetes (pupil sparing)

18

What symptoms arise with oculomotor nerve lesions

Diplopia - double vision
Ptosis - dropping eyelid
Dilated pupil

19

Describe the route, fibres present and function of the trochlear nerve

Route - longest route because it arises from the posterior midbrain. Enters the orbit through the superior orbital fissure
Fibres - motor
Function - motor innervation of superior oblique

20

How can the trochlear nerve be tested

Eye movements

21

Causes of trochlear nerve damage

Head injury
Congenital palsies

22

Symptoms of trochlear nerve damage

Diplopia worse on downward gaze

23

Describe the fibres present and function of the trigeminal nerve

Fibres - Motor, autonomic and sensory
Function - mastication and sensory innervation to most of the face

24

Branches of the trigeminal nerve and where they exit the skull

Ophthalmic - superior orbital fissure
Maxillary - foramen rotundum
Mandibular - foramen ovale

25

What does the ophthalmic nerve supply

Frontonasal prominence
Scalp
Forehead
Orbit
External nose
Lacrimal gland
(Does corneal reflex)

26

What does the maxillary nerve supply

Skin around the upper jaw
Glands of the nose

27

What does the mandibular nerve supply

Motor - muscles of mastication
Sensory - side of the head, cheeks, anterior 2/3 tongue, chin, lower lip
Autonomic - parotid gland

28

How do you test the trigeminal nerve

Test corneal reflex - involuntary blinking by touching the cornea

29

How can the trigeminal nerve be damaged

Herpes zoster infection
Trigeminal neuralgia
Trauma

30

Describe the route, fibres present and function of the abducent nerve

Route - runs in the dura mater passes through the cavernous sinus and into the orbit via the superior orbital fissure
Fibres - motor
Function - in rebates the lateral rectus muscle