ch 18 cranial nerves

Question 1

cranial nerve I

Answer 1

• olfactory nerve
• sensory but can be mixed
• smell: olfactory bulbs - through ethmoid, olfactory tracts - cerebral cortex, anosmia (without smell)

Question 2

cranial nerve II

Answer 2

• optic nerve
• sensory only
• vision: optic tracts - thalamus - primary visual cortex, optic chiasm - 2 optic nerves unite (transfer to opposite side), optic nerve to eyeball, anopia (without vision)
• receptors are rods and cones in retina (detect light, send through optic nerve to send to brain, then to optic chiasm)

Question 3

crainal nerve III, IV, VI

Answer 3

• motor axons leaving from brain headed out to muscles and around eye
• oculomotor (III): motor, movement of eyes and eyelid, and pupil size
• trochlear (IV): smallest nerve, motor, only sends to superior oblique muscle of eye
• abducens (VI) (6): motor, sends motor messages to lateral rectus muscle of eye (makes eyeballs abductions)

Question 4

cranial nerve V

Answer 4

• trigeminal (largest of all cranial nerves)
• mixed: motor and sensory
• 3 branches: V1: sensory (forehead, upper eyelid), V2: sensory (upper teeth, palate, lip), V3: MIXED (mastication muscles

Question 5

cranial nerve VII

Answer 5

• facial: mixed (sensory: return from anterior tongue, taste, balance, proprioception from face (happy, sad, mad face)
• motor: facial movements, smile, frown, and eyebrows
• damage to this nerve = bell’s palsy

Question 6

cranial nerve VIII

Answer 6

• vestibulocochlear: sensory only, auditory nerve, hearing and balance, equilibrium, vertigo, tinnitus
• vestible: fluid determines body position
• cochlea: 1st receptor is hair cells returning sound/vibration

Question 7

cranial nerve IX

Answer 7

• glossopharyngeal: pharynx upper respiratory, mixed
• motor: swallowing, dysphagia (difficulty swallowing)
• sensory: taste, ageusia (loss of taste), aptyalia (loss of sensation or feeling in throat)
• gag reflex: cranial bc integration happens in brain

Question 8

cranial nerve X

Answer 8

• vagus everyone is a 10 in vegas, mixed
• sensory: hunger, fullness, baroreceptors (pressure), chemoreptors (chemicals/gases)
• motor: speak, swallow, cough
• gag reflex (with IX): ANS - parasympathetic (autonomic feedback), vagal neropathy (loss of conciousness)

Question 9

cranial nerve XI

Answer 9

• spinal accessory, mixed
• 2 muscles trapezius and ?

Question 10

cranial nerve XII

Answer 10

• hypoglossal: gloss = tongue
• motor only
• speech: dysarthria (difficulty speaking)
• swallowing: dysphagia