Cranial nerves

Question 1

Cranial Nerve #1

Answer 1

Olfactory
Sensory
Fxn: smell
Location: receptors are in olfactory part of nasal mucosa in the roof of nasal cavity (along medial wall of superior nasal concha).  The olfactory fibers pass through foramina in cribriform plate and enter olfactory bulb in anterior cranial fossa. The nerve fibers synapse with mitral cells in the olfactory bulb and the axon of these cells form the olfactory tract which conveys the impulses to the brain. 
Cranial Exit:  cribriform plate

Question 2

Cranial Nerve #2

Answer 2

Optic
Sensory
Fxn: vision
Location:  From retina the nerve exits the optic canal to enter middle cranial fossa where it forms the optic chiasma. This is where fibers from the medial half of each retina decussate in the chiasma and join uncrossed fibers from the lateral half of the retina to form the optic tract, this allows for binocular vision (depth perception) .  So fibers from the right halves of both retinas form the right optic tract and fibers from the left halves form the left optic tract.  
Cranial Exit:  optic canal

Question 3

Cranial Nerve #3

Answer 3

Oculomotor
Motor
Fxn: powers superior rectus, inferior rectus, medial rectus, inferior oblique, and levator palpebrae superioris muscles.
Cranial Exit: superior orbital fissure

Question 4

Cranial Nerve #4

Answer 4

Trochlear
Motor
Fxn: motor to superior oblique muscle of the eye
Location: Travels from midbrain and then along the lateral wall of the cavernous sinus and then passes into the superior orbital fissure into the orbit.
Cranial Exit: superior orbital fissure

Question 5

Cranial Nerve #5

Answer 5

Trigeminal (3 branches)

Ophthalmic: sensory, passes through superior orbital fissure. Supplies orbital structures, nasal cavity, skin of forehead, upper eyelid, eyebrows and superior nasal cavity.

Maxillary: sensory, exits through foramen rotundum. Supplies lower eyelid, superior lip, gums and teeth, anterior cheek, lateral part of nose, posterior nasal cavity and maxillary sinus.

Mandibular: mixed, exits through foramen oval.
Supplies sensory innervation to anterior 2/3 of tongue, floor of mouth, mandibular teeth, lower lip, buccal, parotid and temporal regions of face, and external ear.
Supplies motor innervation to muscles of mastication (masseter, temporalis, pterygoid muscles).

Question 6

Cranial Nerve #6

Answer 6

Abducens
Motor
Fxn: motor to lateral rectus to turn eye laterally (abduct)
Cranial Exit: Superior orbital fissure

Question 7

Cranial Nerve #7

Answer 7

Facial (5 branches) - Temporal, zygomatic, buccal, mandibular, cervical
Sensory and motor
Fxn: facial expression, salivation, lacrimation, and taste
Cranial exits: internal acoustic meatus to facial canal, exits at stylomastoid foramen.

Question 8

Cranial Nerve #8

Answer 8

Vestibulocochlear
Sensory
Fxn: hearing and equilibrium
Exit: into internal acoustic meatus

Question 9

Cranial Nerve #9

Answer 9

Glossopharyngeal
Sensory and Motor
Fxn: swallowing, salivation and taste
Sensory: posterior 1/3 of tongue, posterior pharynx, receptors for blood pressure, pH, oxygen and carbon dioxide concentrations (carotid body and sinus)
Motor: pharyngeal muscles and parotid salivary gland
Exit: jugular foramen

Question 10

Cranial Nerve #10

Answer 10

Vagus
Sensory and motor
Sensory: input from the mouth, thorax, heart and abdomen
Motor: to soft palate, larynx, visceral organs of the thoraco, abdominal, and pelvic cavities.
Exit: jugular foramen

Question 11

Cranial Nerve #11

Answer 11

Spinal Accessory (2 branches - cranial and spinal)
Motor
Fxn: Spinal - powers the sternocleiodomastoid and trapezius
Cranial - helps to power the soft palate, pharynx and joins up with the Vagus nerve
Exits: Enters the foramen magnum and exits the jugular foramen

Question 12

Cranial Nerve #12

Answer 12

Hypoglossal
Motor
Fxn: powers the intrinsic and extrinsic muscles of the tongue
Exit: hypoglossal canal