Lectures 8, 10: Brainstem and Cranial Nerves Flashcards Preview

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Flashcards in Lectures 8, 10: Brainstem and Cranial Nerves Deck (46):
1

The trochlear nerve emerges __________ and wraps around the brainstem at what junction?

Ventrally; at the junction b/t the midbrain and pons

2

Motor nuclei are _______ and sensory nuclei are _______

Medial; lateral

3

Cortical innervation of cranial nerves is bilateral in all cases except (2)

Portion of VII and XII

4

What is the significance of bilateral cortical innervation of cranial nerves?

Unilateral cortical lesion would not impact nerve function

5

What is the sole CN that crosses the midline?

IV

6

Discuss the anatomy of the olfactory nerve

Short primary sensory nerves (cranial nerves) --> (cribiform plate) --> Olfactory bulb --> primary olfactory cortex

7

What is one way to damage olfactory nerve fibers? What process of the cell is damaged?

Anterior cranial fossa fractures; primary axons

8

How do you test for CSF rinorrhea?

Glucose or beta 2 transferrin

9

Anosmia

Loss of sense of smell

10

Parosmia

Perverted sense of smell

11

Olfactory hallucinations are often caused by...

Temporal lobe (parahippocampal) seizures

12

How do you test olfactory nerve function?

Coffee/vanilla, one side at a tie; note: don't use an irritating smell

13

Temporary anosmia caused by colds affects what level of the olfactory system?

The receptors

14

What are four ways to damage the central processing structures of the olfactory system?

Contusion/laceration of olfactory bulb, aneurysm, olfactory groove meningioma, frontal lobe tumor

15

What are the 3 trigeminal sensory nuclei and what do each control?

1. Spinal trigeminal: crude touch; 2. Pontine Trigeminal (chief): discriminative touch; 3. Mesencephalic: proprioception from muscles of mastication

16

Where is the trigeminal motor nucleus?

The pons

17

What are the 3 branches of the trigeminal nerve and where does each exit the skull?

V1: Opthalmic, superior orbital fissure; V2: Maxillary, foramen rotundum; V3: Mandibular, foramen ovale

18

Where are the cell bodies of the sensory fibers of the trigeminal nerve?

Trigeminal ganglion

19

What is unique about the cell bodies that control the jaw jerk reflex?

They are located in the mesencephalic nucleus, not the trigeminal ganglion

20

What is one common condition associated with the trigeminal nerve? Describe this condition and a common cause

Trigeminal neuralgia; triggered by light touch/gustatory, rarely during sleep, pain-free intervals; common cause: vascular compression due to oligodendrocyte myelination

21

The jaw deviates to the ________ side

Affected

22

To test the 1st branch of the trigeminal ganglion, you can check which reflex?

Corneal

23

What virus often effects the trigeminal nerve? What is one complication that must be evaluated for?

Herpes zoster; herpes opthalmicus (if it affets the opthalmic division)

24

Why is the trigeminal nerve associated with an parasympathetic reflex?

Very close to superior salivatory nucleus --> sinus symptoms, watery eyes

25

Where is the facial motor nucleus? The part of the nucleus supplying forehead muscles gets what type of innervation? What about lower facial muscles? What two muscles besides muscles of facial expression?

Pons; bilateral; contralateral; stapedius (dampens sound) and part of digastric

26

Where are the cell bodies of the sensory fibers of the facial nerve? What nerve connects this ganglion to the brainstem nuclei?

Geniculate nucleus; nervous intermedius

27

What does the GSA section of the facial nerve control? What nucleus?

Ear sensations (concha, behind ear, external auditory canal); spinal trigeminal

28

What does the SVA section of the facial nerve control? What nucleus? What special nerve?

Taste from anterior 2/3 of tongue; solitary nucleus; chorda tympani

29

What does the GVE section of the facial nerve control? What two nerves? What nucleus?

Lacrimal gland via V2 branches; Submandibular and sublingual via chorda tympani; superior salivatory nucleus

30

Describe the basic anatomy of the facial nerve

Exits brainstem through cerebellopontine angle --> internal auditory meatus and facial canal --> stylomastoid foramen

31

A lower motor neuron lesion causes facial palsy where? What are three common causes?

Palsy on same side as lesion on upper and lower face; Bell's palsy, meningeal process (Guillain-Barre), or a stroke involving the VII nucleus

32

An upper motor neuron lesion causes facial palsy where? What is a common cause?

Palsy on contralateral side as lesion on lower face only; stroke

33

Describe the fives types of information carried by the Glossopharyngeal nerve

SVE: stylopharyngeus (swallowing); GVE: parotid gland; GSA: middle ear; SVA: taste from posterior 1/3 of tongue; GVA: touch from pharynx and posterior 1/3 of tongue, afferent limb of gag reflex, carotid body/sinus

34

Describe the basic anatomy of the glossopharyngeal nerve. What are the associated nuclei?

Exits the brainstem ventrally from upper medulla --> jugular foramen; spinal trigeminal, nucleus ambiguus, solitary nucleus, caudal solitary nucleus, inferior salivatory nucleus

35

Lesions of the glossopharyngeal nerve can cause (5)

Difficulty swallowing, taste impairment, impaired gag refelx, reduced saliva, syncope

36

One condition unique to glossopharyngeal nerve

Glossopharyngeal neuralgia

37

Describe the basic anatomy of the vagus nerve

Exist the brainstem from the medulla --> jugular foramen --> carotid sheath (inbetween internal carotid and internal jugular)

38

The vagus nerve synapses on what four nuclei? Fiber type and functions?

1. Dorsal nucleus of vagus nerve (GVE, parasympathetic output to viscera --> left colic flexure); 2. Nucleus ambiguus (SVE, brachial muscles of larynx/pharynx, upper esophagus, palate); 3. Solitary nucleus (SVA and GVA, epiglottal taste and sensation from mouth --> L colic flexure); 4. Trigeminal nucleus (GSA, dura, external ear and tympanic membrane)

39

Six main functions of vagal nerve

Phonation, swallowing, palate elevation, taste, cutaneous sesnastion from ear, and visceral innervation (neck --> L colic flexure)

40

What are some symptoms of vagal problems (4)

Loss of gag reflex, paralysis of soft palate (dyspnea, dysarthria, dysphagia), parasympathetic disturbances, lowering of palate and deviation of uvula

41

What is unique about the uvula?

Deviates TOWARD normal side

42

What are the two divisions of the spinal accessory nerve and how are they anatomically similar and different? What do they innervate?

Cranial division arises from the nucleus ambiguus --> jugular foramen --> intrinsic muscles of larynx but NOT cricothyroid; Spinal division arises from the ventral horn of C1 - C6 --> foramen magnum --> jugular foramen --> sternocleidomastoid and trapezius

43

Three clinical correlations of the spinal accessory nerve

1. Difficulty turning head to contralateral side; 2. Shoulder droop; 3. Larynx paralysis

44

Describe the anatomy and basic function of the hypoglossal nerve

Mediates tongue movement; hypoglossal nucleus --> hypoglossal canal --> intrinsic and extrinsic tongue muscles

45

If LMNs are involved, the how does the tongue deviate? IF UMNs?

Toward lesion; away from lesion

46

What is Pseduobulbar palsy?

Bilateral corticobulbar tracts involved; inability to control facial movements, swallowing, spastic speech, emotional outbursts

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