What are the two types of general afferent fibers?
General Somatic Afferents
General Visceral Afferents
General afferent fibers are sensory fibers. Where do we find their cell bodies of origin?
(Dorsal root ganglia; nuclei/ganglia of the specific cranial nerves)
What are the two broad types of impulses that are conducted via general somatic afferents?
List three examples of exteroceptive impulses.
Where do these impulses originate?
From epithelium of ectodermal origin
Where do proprioceptive impulses originate from?
Sensory endings in the -
- Body wall
What afferent fiber types innervate blood vessels?
Where are the "special" fiber types found?
Only in the cranial nerves
What are the types of special afferent fibers?
Special Somatic Afferent (SSA)
Special visceral afferent (SVA)
What are SSA's connected to?
What roles do they function in?
Ear and Eye
Hearing, vision and equilibrium
Where are special visceral afferent fibers found?
What role do they play?
Nose and mouth
Olfactory (smell) and gustatory (taste
Why are SVA's named as visceral?
Because of the functional association of these sensations with the digestive tract.
What are general efferent fibers?
Motor fibers that innervate the musculature of the body.
What muscles do not recieve general efferent fibers?
What are the types of general efferent fibers?
General somatic efferent (GSE)
General Visceral Efferent (GVE)
What do GSE's innervate?
Somatic (skeletal) muscles
What are GVE's divided into?
Sympathetic and Parasympathetic
What are the two types of special efferent fibers?
Special visceral efferent (SVE)
Special Somatic Efferent (SSE)
What do SVE's innervate?
Skeletal muscles derived from the visceral (branchiomeric/pharyneal) arch mesoderm
SVE's innervate muscle derived from branchiomeric/pharyngeal arch mesoderm. What are these muscles involved in?
Mastication, facial expression, pahrynx, palate and larynx
In what way does the autonomic nervous system influence SVE's?
It does not. The visceral designation has naught to do with autonomics.
What do SSE's do?
Reflexively influence sensory input to the ear
What cranial nerves carry General somatic efferent fibers?
What cranial nerves carry SSE's?
What cranial nerves carry GVE's?
What cranial nerves carry SVE's?
What nerves carry GSA's?
(proprioception and exteroception)
All spinal nerves
All spinal nerves
CNL V, VII, IX, X
What cranial nerves carry GVA's?
What cranial nerves carry SVA's?
Taste via : VII, IX, X
Smell via: I
What fiber types do spinal nerves carry?
What is Cranial nerve I responsible for? What is it's designation?
Olfaction - causes reflex salivation and increased gastric motility.
(Thus designated a visceral afferent nerve)
What is the function of cranial nerve II?
What is it's designation?
Afferent fibers for the retina, primary receptor for the sense of sight.
What is cranial nerve III responsible for? What is it's designation?
The oculomotor nerve has two designations, GSE and GVE-P.
- GSE - The motor component innervates the extraocular muscles of the eye, which assist in roational movement of the globe (eye).
- GVE-P - Parasympathetic innervation of intra-ocular muscles of the eye. Responsible for changing the shape of the lens for accommodation and for narrowing the pupil.
GVE-P of CN III operates via what division and ganglion?
What is the function of CN IV? What is it's designation?
Why is it named the way it is?
The trochlear nerve innervates one extra-ocular muscle - the superior oblique.
The muscle utilizes a pulley to carry out its action, the nerve carries the name of the pulley - the Trochlea
What is the name of CN V?
What is the GSA component of the Trigeminal nerve responsible for?
GSA - Major sensory nerve of the head, it innervates:
- portion of the scalp
- most of the face
- all conjunctiva
- epithelium of the nasal cavity
- paranasal sinuses
- skin of outer ear
- external auditory meatus
- external surface of the tympanic membrane
- cranial dura mater
- Proprioception of All skeletal muscles of the head
What is the SVE component of Cranial nerve V responsible for?
Motor innervation to skeletal muscles of pharyngeal arch origin. Specifically:
- muscles of mastication (4)
- anterior belly of the digastric muscle
- tensor veli palatini
- tensor tympani muscles
Describe the GVE-P components of the Trigeminal nerve.
The nucleus of the trigeminal nerve does not contain GVE-P cell bodies/fibers of its own.
However, since it distributes to the majority of structures in the head and face, it is utilized as a carrier for GVE-P fibers of CN's:
and distributes their fibers to the smooth muscles of the eye and to the glands of the head.
What CN distribute their GVE-P's along the trigeminal nerve?
What is the name of CN VI, and why is it so named? What is its designation?
What is it responsible for?
Abducens - since the innervated muscle turns the eye laterally, it is named for its ability to abduct the eye.
Innervation of one extraocular eye muscle: Lateral rectus
What is the name of CN VII? What are it's fiber designations?
What is the SVE role of the facial nerve?
Motor innervation to mskeletal muscles of pharyngeal arch origin. Specifically the second arch -
- Muscles of facial expression
- posterior belly digastric muscles
What does the GSA component of CN VII do?
Sensory to a portion of the skin of the external ear and external auditory meatus.
What does the SVA component of the facial nerve do?
Taste to the anterior 2/3 of the tongue via chorda tympani.
What is the GVA component of the Facial nerve responsible for?
Sensory to the uppermost portion of the pharynx
What are the GVE-P via the greater petrosal nerve from the facial nerve responsible for? What ganglion is associated with this?
Parasympathetic innervation to the...
- lacrimal gland
- pharyngeal mucous glands
What are the GVE-P from CN VII wia the chorda tympani and the submandibular ganglion responsible for?
Innervation to the submandibular and sublingual salivary glands
What is the name and designation of CN VIII?
What is the role of the SSA component of the vestibulocochlear nerve fibers?
Afferent from the organ of Corti - related to the sense of hearing
Afferent from the semicircular canals, utricle and saccule of the internal ear relative to the sense of equilibrium.
What do the SSE fibers from CN VIII do?
Motor fibers related to modifying auditory input
What is the name of CN IX? Designations?
What is the SVE component of the glossopharyngeal nerve responsible for?
Motor innervation to skeletal muscle of pharyngeal arch origin, specifically arch three - stylopharyngeus
What is the GSA portion of CN IX responsible for?
Sensory to a portion of the skin of the external ear.
What is the SVA component of the glossopharyngeal nerve responsible for?
Taste from the posterior third of the tongue.
What is the GVA portion of CN IX responsible for?
Sensory to epithelium of endodermal origin which lines...
- majority of pharynx from base of skill to laryngeal aditus
- eustacian tube
- middle ear
- Internal surface of tympanic membrane
- mastoid air cells
- Posterior thurd of the tongue
- parotid gland
- carotid sinus
What is the GVE-P component of CN IX responsible for? How do they get to their destination?
Secretory fibers to the parotid salivary gland via the lesser petrosal nerve and the otic ganglion
What is the name of CN X? What are the fiber designations associated with this nerve?
What is the SVE component of the Vagus responsible for?
- Motor innervation to skeletal muscles of pharyngeal arch origin, specifically arches four and six. Including the pharynx and palate, larynx and upper portion of the esophagus.
What is the GSA component of the Vagus responsible for?
Cutaneous innervation to the skin of the -
- external ear
- external auditory meatus
- external surface of the tympanic membrane
- dura mater of the posterior cranial fossa
What is the SVA component of the Vagus nerve responsible for?
Taste from the epiglottic surface of the tongue in the area of the epiglottic valleculae
What is the GVA component of the Vagus responsible for?
Sensory innervation to the epithelium of endodermal origin, which lines the:
- root of the tongue
- lining of the respiratory system
- entire gut tube to distal third of transverse colon to capsule of other visceral organs
What is the role of the GVE-P fibers of the Vagus?
Parasympathetic innervation to mucous glands in the larynx, smooth muscle and glands of the gut tube to the distal third of the transverse volon, respiratory system and to cardiac muscle.
What is the name of CN XI? What is its designation? What does it do?
Spinal accessory nerve
Motor innervation to the sternocleidomastoid and trapezius muscles.
What is the name of CN XII?
Motor innervation to the muscles of the tongue:
- Intrinsitc muscles of the tongue