Pure Sensory Cranial Nerves

Front 1

What are the three pure sensory cranial nerves? What are these cranial nerves responsible for?

Back 1

Cranial Nerves 1, 2, and 8; Olfactory Nerve, Optic Nerve, Vestibular Cochlear Nerve; These nerves are concerned with SPECIAL SOMATIC SENSES

Front 2

What is cranial nerve 1 responsible for?

Back 2

Olfactory Nerve; Special somatic sensory; smell

Front 3

How is CN1 different from the other CNs in structure?

Back 3

The olfactory nerve does not contain a single bundle of axons, but rather 20 or so separate bundles arising from olfactory cells scattered along the epithelial cells in the nasal cavity; note that the olfactory nerve is the only nerve that does not attach to the brainstem (attaches to telencephalon)

Front 4

What type of neurons are the olfactory nerves?

Back 4

Bipolar neurons; their processes merge to make a plexiform network, which give rise to bundles of nerves, which in turn give rise to olfactory nerve, proper

Front 5

Describe the passage of the olfactory nerve through the skull (CN1)

Back 5

Through the cribiform plate--> piece of ethmoid bone-->through dura and arachnoid-->olfactory bulb-->synapse at mitral cells-->olfactory tracts-->telencephalon

Front 6

What can cause a loss of smell?

Back 6

Breakage of the olfactory bulbs; unbalanced degeneration of olfactory cells at 1% each year (usually regenerate)

Front 7

What is the function of CN II?

Back 7

CN II= optic nerve; special somatic sensory nerve = vision

Front 8

Describe the origin of CN II and its passage through the skull

Back 8

Nerve begins at retina at back of eyeball-->converges at optic disk to become continuous with optic nerve (at optic chiasma)-->fibers continue to thalamus or midbrain (lateral geniculate ganglion or superior colliculi ganglion)--> pass to occipital cortex where visual impulses are decoded

Front 9

Why is the optic nerve surrounded by meninges?

Back 9

Because it originates at the retina, which is an outgrowth of the brain

Front 10

What types of cells lengthen to form rods and cones?

Back 10

Bipolar cells; ganglion cells synapse at bipolar cells

Front 11

What is the effect of having lateral fibers stay on the same side after the nerve fibers cross at the optic chiasma?

Back 11

Neurons in related visual field are carried in the same optic tract

Front 12

Describe the movement of the CNII fibers after they converge to form the optic nerve

Back 12

Medial fibers cross to opposite side and lateral fibers stay on the same side at the optic chiasma

Front 13

What is the function of CNVIII

Back 13

Vestibular Cochlear Nerve; responsible for hearing and balance; special somatic sensory nerve

Front 14

Where does CNVIII originate? Trace its path through the skull

Back 14

Originates from cochelar ganglion and vestibular ganglion-->fibers converge and pass through internal acoustic meatus-->pass through posterior cranial fossa and enters pons and medulla; n.b. CN VIII NEVER exits the skull (unique)- stays in petrous temporal bone

Front 15

What is the location of the vestibular ganglion?

Back 15

The semicircular canals

Front 16

Where are the cell bodies of CNI?

Back 16

Nasal mucosa

Front 17

Where are the cell bodies of CN II?

Back 17

Retina

Front 18

Where are the cell bodies of CNVIII

Back 18

Vestibular ganglion (semicircular canals); spiral ganglion (cochlea)

Front 19

What structures pass through the superior orbital fissure?

Back 19

Oculomotor (3), Trochlear (4), Trigeminal-opthalmic nerve (V1), Abducens (6); superior opthlamic vein

Front 20

What structure passes through the foramen spinosum?

Back 20

The middle meningeal artery

Front 21

What structure(s) pass through the internal acoustic meatus?

Back 21

Facial Nerve (CN7); Vestibulocochlear nerve (CN8)

Front 22

What structure(s) pass through the hypoglossal canal?

Back 22

CN12; hypoglossal nerve

Front 23

What structure(s) pass through the foramen magnum?

Back 23

The spinal cord and vertebral arteries

Front 24

What structure(s) pass through the foramen cecum?

Back 24

The emissary veins to the superior saggital sinus

Front 25

What structure(s) pass through the cribiform plate?

Back 25

The olfactory nerve=CNI

Front 26

What structure(s) pass through the optic canal?

Back 26

CN 2 (optic nerve) and opthlamic artery

Front 27

What structure(s) pass through the foramen rotundum?

Back 27

The trigeminal nerve (CNV2)- maxillary nerve

Front 28

What structure(s) pass through the foramen ovale?

Back 28

The mandibular nerve (CNV3)

Front 29

What structure(s) pass through the foramen lacerum?

Back 29

The internal carotid artery

Front 30

What structure(s) pass through the jugular foramen?

Back 30

The internal jugular vein, CN 9 (glossopharyngeal), CN 10 (vagus) and CN XI (accessory)

Front 31

What are the two types of vestibular sensory fibers of CNVIII?

Back 31

1) Fibers that detect static equilibrium (from sacculus and utricle); 2) Fibers that detect dynamic equilibrium (semicircular canals)

Front 32

What embryonic region does CNI originate from?

Back 32

The CNS = ectoderm

Front 33

What embryonic region does CNII originate from?

Back 33

Diencephalon

Front 34

What embryonic region does CNVIII originate from?

Back 34

Metencephalon