Cranial Nerves Flashcards
how many pairs of cranial nerves are there and where do they originate
12 pairs
one pair from cerebrum (I)
one pair from diencephalon (II)
nine pairs from brainstem
one pair from the spinal cord (XI)
what cranial nerve originate in the brain but also the spinal cord?
cranial nerve XI
(accessory nerve)
Name the cranial nerves in order
Olfactory bulb (olfactory nerves (I) enter bulb)
Optic nerve (II)
Oculomotor nerve (III)
Trochlear nerve (IV)
Trigeminal nerve (V)
Abducens nerve (VI)
Facial nerve (VII)
Vestibulocochlear nerve (VIII)
Glossopharyngeal nerve (IX)
Vagus nerve (X)
Hypoglossal nerve (XII)
Accessory nerve (XI)
NOTE: 11 and 12’s numbers are switched
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Olfactory nerve
Nerve I
Sensory
Function: smell
2 neuron system
Components:
- olfactory tract (to cerebral cortex)
- olfactory bulb
- CRIBRIFORM PLATE of ETHMOID BONE
- fibres of olfactory nerve
ORIGINATES in cerebrum
label on diagram
Optic nerve
Nerve II
Sensory
Function: vision
Collected info from retnas
Components
- optic nerve
- optic chiasm
- optic tract
- ORIGINATES just below hypothalamus
label on diagram
Oculomotor nerve
Nerve III
Motor
Function: movements of eyeball and upper lid
- controls 4/6 extrinsic eye muscles
- parasympathetic: controls smooth muscle inside eye to open/close pupil and change lens shape
Components
- nerve branches to different eye muscles
- OGINATES in midbrain
Trochlear nerve
Nerve IV
Motor
Function: movement of eyeball, specifically the trochlea (little pulley that straightens an eye muscle)
ORIGINATES in midbrain
Trigeminal nerve
Nerve V
Motor + sensory
Components: 3 branches
OPHTHALMIC
- sensory: upper facial structures
MAXILLARY
- sensory: middle facial structures
MANDIBULAR
- sensory: lower facial structures + anterior to ear
- motor: masticulation
ORIGIN: pons
can also responsible for headaches and tooth pain
only cranial nerve that carries sensory information from the skin
trigeminal nerve
Abducens nerve
Nerve VI
Motor
Function: lateral movement of eyeball
ORIGIN: pons
remember: abduct -> ABDucens
Facial nerve
Nerve VII
Motor/sensory
Functions
sensory: taste (anterior 2/3)
motor: facial expressions (contracts facial skeletal muscle)
parasympathetic motor: salivary glands/lacrimal (tear) glands
ORIGIN: pons
Vestibluocochlear
Nerve VIII
Sensory
Function: hearing/balance
Components (2 branches coming together)
- vesibular nerve: balance
- cochlear nerve: hearing
ORIGIN: brainstem (between pons and medulla oblongata)
Glossopharyngeal nerve
Nerve IX
Sensory/motor
Functions:
Sensory
- taste (posterior 1/3 tongue)
- monitors swallowing muscles
connected to CAROTID BODY and CAROTID SINUS which help with…
- blood pressure
- blood gasses
Motor
- swallowing
Parasympathetic motor
- PAROTID GLAND (saliva)
ORIGIN: medulla oblongata
Vagus nerve
Nerve X
Motor/Sensory
Functions:
Motor
- voice production
- swallowing
Sensory (thoracic and abdomen cavity)
connected to lungs, heart, liver, stomach, spleen, kidneys, pancreas, SI, colon
- BP/blood gasses, taste
Parasympathetic motor
- GI controls, respiration, lowers HR
ORIGIN: medulla oblongata
Accessory
Nerve XI
Motor
Functions: head movement (controls 2 neck muscles)
ORIGINS: spinal cord, medulla oblongata
reason it’s called the accessory nerve: has some axons connecting to vagus nerve
