Ch. 14 - Brain and Cranial Nerves III

Question 1

some say marry money, but my brother says big brains matter more

Answer 1

to remember which nerves are sensory/mixed/both!

Question 2

oh once one takes (the) ana-tomy final, very good vacations start happening

Answer 2

olfactory, optic, oculomotor, trochlear, abducens, trigeminal, facial, vestibulocochlear, glossopharyngeal, vagus, spinal accessory, hypoglossal

Question 3

What kind of neurons are olfactory receptors? What is their function?

Answer 3

bipolar neurons (axons); relays olfactory info

Question 4

What is the pathway of the olfactory nerve? (CN I)

Answer 4

extends from olf mucosa of nasal cavity –> olf bulb –> olf tracts –> primary olf area in temporal lobe

Question 5

What is the pathway of the optic nerve? (CN II)

Answer 5

retinal cell axons form optic nerve –> merge and some axons cross in optic chiasm –> optic tracts –> thalamus/midbrain –> prim visual area in cerebral cortex

Question 6

What is the function of the oculomotor, trochlear, and abducens nerves? (CN III, IV, VI)

Answer 6

synapse with muscles for moving the eyeballs & upper eyelid

Question 7

What other movement can the CN III perform?

Answer 7

autonomic movement to constrict pupils

Question 8

What is strabismus?

Answer 8

misalignment of the eyes caused by weak muscles

Question 9

What are the 3 branches of the trigeminal nerve?

Answer 9

ophthalamic, maxillary, mandibular

Question 10

Two portions of the trigeminal portion (CN V):

Answer 10

SENSORY - pain, touch, temperature, receptors of face and oral cavity

MOTOR - muscles of mastication

Question 11

Where does the facial nerve arise from?

Answer 11

the pons

Question 12

Two portions of the facial nerve (CN VII):

Answer 12

SENSORY - taste buds on ant 2/3 of tongue

MOTOR - produce facial expressions, salivary/nasal/lacrimal glands

Question 13

What is Bell’s palsy?

Answer 13

facial droop/loss of muscle tone in the face due t odamage to CN VII

Question 14

What are the 2 branches of the vestibulocochlear nerve (CN VIII) ?

Answer 14

V - carries impulses for equilibrium

C - carries impulses for hearing

Question 15

Two portions of the glossopharyngeal nerve (CN IX):

Answer 15

SENSORY - taste buds from post 1/3 of tongue, proprioceptors of swallowing muscles, baroreceptors in carotid sinus, chemoreceptors in carotid artery

MOTOR - swallowing muscles (som), saliva secretion (auto)

Question 16

What would damage to CN IX lead to?

Answer 16

problems swallowing, dry mouth (less activation of salivary glands)

Question 17

Two portions of vagus nerve (CN X)

Answer 17

SENSORY - external ear, baro & chemo receptors, sensation from visceral organs

MOTOR - muscles of pharynx, larynx, soft palate for swallowing/vocalization/coughing, autonomic output to visceral organs

Question 18

Where does the accessory nerve arise from (CN XI)

Answer 18

originates from spinal nerves C1-C5, passes through foramen magnum up to brain

Question 19

Where does the output from CN XI go to?

Answer 19

sternocleidomastoid and trapezius muscles to control head movements

Question 20

Where does the hypoglossal nerve (CN XII) arise from?

Answer 20

medulla

Question 21

What does CN XII control?

Answer 21

muscles of tongue during speech and swallowing

Question 22

How does lidocaine HCl function in pain control?

Answer 22

• stabilizes neuronal membrane by inhibiting ionic fluxes required for initiation/conduction of impulses
• these affects local anesthetic action

Question 23

How do opioids (particularly morphine) affect pain control?

Answer 23

act on receptors on neuronal cell membranes

- presynaptic action of opioids inhibit NT release to produce analgesic response

Question 24

How does aspirin and other non-steroid anti-inflammatory drugs (NSAIDs) affect pain control?

Answer 24

inhibit activity of cyclooxygenase (COX) which leads to formation of prostaglandins (PGs) that cause inflammation, swelling, pain, and fever

Question 25

How does fentanyl control pain?

Answer 25

• induces opening of G-protein-coupled + blocks opening of N-type voltage gated Ca2+ channels, resulting in hyperpolarization + reduced neuronal excitability
• it selectively binds to mu-receptor in CNS mimicking effects of endogenous opiates
• this stimulates the exchange of GTP for GDP on the G-protein complex, inhibiting adenylate cyclase
• results in a decrease in intracellular cAMP; reduces release of substance P, GABA, dopamine, ACh, NE