Cranial Nerves!!! Flashcards
where do sensory fibers have their cell bodies?
craniospinal ganglia
- dorsal root ganglia; nuclie/ganglia of specific cranial nerves
GSA
- receives enteroceptive impulses (pain, temperature, touch) from epithlium of ectodermal origin- all skin, dura mater, anterior 2/3rds of tongue
- receives proprioceptive impulses from sensory endings in the body wall, tendons and joints
ECTODERMAL ORIGIN
GVA
- Fibers carrying sensory impulses (usually pain) from visceral structures within body lined by epithelium
- posterior third of tongue, ducts of parotid gland, carotid sinus, middle ear, larynx, gut, etc.
- ENDODERMAL ORIGIN
- supply blood vessels, even though they are mesoderamlly derived
SSA
Special somatic afferent: found only in cranial nn.
1. ear and eye (vision, hearing, equilibruim from outside)
SVA
special visceral afferent - found only in cranial nn.
- olfactory - smell
- gustatory - taste
* * named visceral b/c of the functional association of senation with digestive tract
GSE
fibers conveying motor impulses to somatic skeletal muscles
- cell bodies located in ventral motor horn
- 3,4,6,11,12
GVE
- cell bodies found in IMLCC
- autonomic fibers which innervate smooth m. of gut tube, blood vessels and cardiac muscle, and fibers for glandular secretion.
- symp: all spinal nn, ANS fibers
- PS: cranial nn: 3,7,9,10
SVE
special visceral efferent
- nerves which innervate the skeletal muscles derived from the visceral arch mesoderm (branchiomeric/pharyngeal)
- muscles of mastication, facial expression, pharynx, palate and larynx
- no ANS control
SSE
nerve fibers which influence sensory input to the ear - “selective hearing”
-8
CN I
Olfactory n.
SVA
- sense of smell
- b/c it assists the body in preparing for eating by causing reflex salivation and an increase in gastric motility, designated as a visceral afferent n.
CN II
Optic n.
SSA
- afferent fibers of the retina; primary receptor for the sense of sight
CN III
Oculomotor: GSE, GVE-P
GSE: motor component innervates extra-ocular muscles of the eye which assist in rotational movment of the the eye
GVE-P: PS innervation of intra-ocular muscles of the eye responsible for changing the shape of the lens for accommodation and pupilary constriction; via inferior division of CN III
CN IV
Trochlear: GSE
- innervation of one extra-ocular eye muscle: superior oblique (“sad eye muscle” - turns eye down and out)
- muscle utilizes a pulley to carry out its action: nerve carrier the name of “the pulley”
CN V
Trigeminal: GSA, SVE
- GSA: major sensory nerve of the head (innervates the scalp, most of face, all conjunctiva and provides all proprioceptive fibers to skeletal muscles of head)
- SVE: motor innervation to skeletal muscles of pharyngeal arch origin- first arch: muscle of mastication (4), mylohyoid, anterior belly of digastric muscle, tensor vli palatinia and tensor tympani muscles.
note: does not contain GVE-P, though GVE-P fibers of CNs III, VII, IX distribute their fibers via this nerve.
CN VI
Abducens: GSE
- innervation of extra-ocular muscle: lateral rectus
- turns the eye laterally - named for ability to abduct the eye
CN VII
Facial: SVE, GSA, SVA, GVA, GVE-P (all but SSA)
- SVE: motor innervation to skeletal muscles of second arch origin: muscles of facial expression, sylohyoid, posterior belly digastric muscle, stapedius
- GSA: sensory to a portion of the skin of the external ear and external auditory meatus
- SVA: taste to anterior 2/3 of tongue via chorda tympani
- GVA: sensory to uppermost portion of pharynx
- GVE-P: PS to lacrimal gland, nasal, palatal, oral and pharyngeal mucous glands via greater petrosal n. and pterygopalatine ganglion; to the submandiular and subliqual salivary glands via chorda tympani and submandibular ganglion
CN VIII
Vestibulocochlear: SSA, SSE
- SSA: affarent fibers from organ of Corti (sense of hearing). Afferent fibers from semicircular canals, utricle and saccule of internal ear relative to sense of equilibrium
- SSE: motor fibers related to modifying auditory input.
CN IX
Glossopharyngeal: SVE, GSA, SVA, GVA, GVE-P
- SVE: motor innervation of arch three: stylopharyngeus
- GSA: sensory to portion of external ear
- SVA: taste from posterior third of tongue
- GVA: sensory to epithelium of endodermal origin which lines the majority of pharynx, middle ear, internal tympanic membrane, tonsils, posterior third of tongue, parotid gland, carotid sinus.
- GVE-P: secretory fibers to the parotid salivary gland via the lesser petrosal n. and otic ganglion
CN X
Vagus: SVE, GSA, SVA, GVA, GVE-P
- SVE: motor innervation to skeletal muscles or arches 4 and 6: muscles of pharynx, palate, larynx and upper portion of esophagus
- GSA: Cutaneous innervation of skin of external ear, external auditory meatus, external TM and dura mater of posterior cranial fossa
- SVA: taste from epiglottic surface of tongue in area of epiglottic valleculae
- GVA: sensory of tongue, larynx, resp system, heart, gut tube, transverse colon and liver, spleen kidney and gonads
- GVE-P: PS of mucous glands of larynx, smooth m. glands of gut tube, distal third of transverse colon, resp. system and cardiac.
CN XI
Spinal Accessory: GSE
- motor innervation to sternocleidomastoid and trapezius m.
CN XII
Hypoglossal: GSE
- motor innervation to muscles of tongue: styloglossus, genioglossus, hyoglossus, and intrinsic muscles of tongue
