2.5 Cranial Nerves Flashcards
Are there 12 individual cranial nerves
No there are 12 pairs, with each pair having one nerve on the right and one nerve on the left
What are the 12 cranial nerve pairs and what area does each one control
- Olfactory - smell
- Optic - vision
- Oculomotor – eye movements
- Trochlear – eye movements
- Trigeminal – motor to muscles of mastication and general sensory to the face
- Abducens – eye movements
- Facial – muscles of facial expression
- Vestibulocochlear – hearing and balance
- Glossopharyngeal – swallowing, taste
- Vagus – wandering nerve supplying heart, lungs, gut
- Spinal accessory – neck muscles
- Hypoglossal– muscles of the tongue
How are the cranial nerves typically numbered
Using roman numerals
What are the 3 different pathways that a cranial nerve can take
-motor to voluntary
-motor to involuntary
-sensory
What are the 2 motor to voluntary muscle pathways
somatic motor - not from pharyngeal arches
brachial motor - from pharyngeal arches
What are the 3 sensory pathways
general sensation, special senses or senses from viscera (e.g lungs or bronchi)
Describe the olfactory nerve (CN I)
-special sensory
-only responsible for smell, innervates the olfactory epithelium (which can regenerate) which lines nasal cavity with nasal septum, nasal mucosa and superior conchae
-defects in this causes anosmia
Describe the optic nerve (CN II)
-special sensory
-nerve cell bodies in the retina, exits the orbital canal, processes vision from the retina
-defects in this can be a sign of multiple sclerosis
Describbe the oculomotor nerve (CN III)
-somatic motor and visceral motor
-its somatic motor functions supply the midbrain (Superior rectus, medial rectus, inferior oblique, levator palpebrae superioris, helping to control eye movement)
-its visceral motor functions supply the sphuncter pupillae and ciliary muscle via the cilliary ganglion
Describe the trochlear nerve (CN IV)
-somatic motor
-the somatic motor functions supply cell bodies located in the midbrain, supplies the superior oblique muscle which moves the eye down
Describe the trigeminal nerve (CN V)
-general sensory
-has 3 branches; opthalmic, maxillary and mandibular
opthalmic- general sensory, sensation from cornea, forehead, scalp, eyelids, nose etc
maxillary- general sensory, sensation for upper lip, face over maxilla, maxillary teeth and maxillary sinuses
mandibular- general sensory, sensation to the chin, 2/3 of tongue, mandibular teeth and supplies muscles for chewing
Describe the abducens nerve (CN VI)
-somatic motor
-nerve arises from the pons in the eye, the motor function goes to the lateral rectus, controls the ipsilateral eye abduction movement
Describe the facial nerve (CN VII)
-branchial motor, special sensory and visceral motor
-branchial motor- motor to muscles of facial expression, scalp and stapedius
-special sensory- gives taste to anterior 2/3 of tongue and palate
-visceral motor- innervates the submandibular and sublingual salivary glands, lacrimal gland and glands of nose and palate
Describe the vestibulocochlear nerve (CN VIII)
-special sensory
-gives vestibular sensation (semicircular ducts), hearing from the spiral organ
Describe the glossopharyngeal nerve (CN IX)
-somatic motor, somatic sensory, visceral motor, visceral sensory and special sensory
-somatic motor- motor to stylopharyngeus
-visceral motor- innervates parotid gland
-visceral sensory- parotid gland, pharynx, middle ear
-special sensory- 1/3 of the tongue taste
-somatic sensory- external ear
