test 3: CN Flashcards
break down of the PNS
~ 36 nerves: 8 Cervical; 13 Thoracic; 7 Lumbar; 3 Sacral; and ~ 5 Caudal.
a spinal nerve contains what types of fibers
Somatic Afferents (SA)
Visceral Afferents (VA)
Somatic Efferents (SE)
Visceral Efferents (VE).
label
somatic afferent and visceral afferent have their bodies where?
dorsal root ganglion
(pseudo unipolar- This type of neuron contains an axon that has split into two branches; one branch travels to the peripheral nervous system and the other to the central nervous system.)
pseudounipolar
A pseudounipolar neuron is a type of neuron which has one extension from its cell body. This type of neuron contains an axon that has split into two branches; one branch travels to the peripheral nervous system and the other to the central nervous system.
example: SA and VA: cell body in dorsal root ganglion
SE their cell bodies where?
SE: cell body in the spinal cord- one nerve synapses on the skeletal muscle
VE axons have cell bodies where?
two part communication
autonomic: sympathetic or parasympathetic
cell body in spinal cord then can synapse down the communicating ramus in the paravertebral ganglion→ back up and down spinal nerve to smooth muscle of blood vessels or skin
or
down the communicating ramus → splanchnic nerve→ synapse on a prevertebral ganglion → continue to GI
The ___: axons that carry impulses from somatic or visceral structures to the central nervous system (CNS)
‘A’ stands for afferent (sensory
The ____: axons that carry impulses away from the CNS to somatic or visceral structures.
‘E’ stands for efferent (motor)
___ carry motor impulses from the CNS to peripheral motor ganglion that innervates smooth muscle, cardiac muscle, or gland cells.
Visceral efferent fibers (VE)
Special Afferents
Special afferent fibers carry sensation to the brain from special senses found only in the head (olfaction, vision, balance, hearing, taste).
Special efferents
Special efferent fibers (SE) carry motor impulses from the brain to striated muscle (branchiomeric) derived embryonically from the branchial arches (formally gills in aquatic animals). These will be considered as SE fibers along with the other SE fibers innervating non-branchiomeric striated muscles.
Cranial nerves
- Olfactory (CNI)
- Optic (CNII)
- Oculomotor (CNIII)
- Trochlear (CNIV)
- Trigeminal (CNV)
- Abducens (CNVI)
- Facial (CNVII)
- Auditory (Vestibulo-cochlear) (CNVIII)
- Glossopharyngeal (CNIX)
- Vagus (CNX)
- Spinal Accessory (CNXI)
- Hypoglossal (CNXII).
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sensory or motor CN
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which cranial nerves have sensory axons and possess sensory ganglia?
V, VII, IX, and X
trigeminal, facial, glossopharyngeal and vagus
(most sensory ganglion you can’t see expect for the distal ganglion of vagus)
which cranial nerves contain special sensory?
1,2,7,8,9,10
what cranial nerve contains special sensory for smell?
1 olfactory
what cranial nerve contains special sensory for taste?
7,9,10
facial, glossopharyngeal and vagus
what cranial nerve contains special sensory for vision
2 -optic nerve
what CN contains special sensory for hearing and balance
CN8, vestibulocochlear
which CN contain VE axons that are part of the parasympathetic division?
3,7,9,10
oculomotor, facial, glossopharyngeal and vagus
VE fibers of the CN 3,7,9, and 10 supply ___
such visceral structures as the: smooth muscles of the Iris and Ciliary Body of the eye and the Salivary and mucous glands.
Sympathetic Division axons from the upper thoracic segments of the spinal cord ascend the sympathetic and vago-sympathetic trunks, synapse on ___ neurons in the ____
postganglionic
Cranial Cervical ganglion.
Postganglionic axons of the Cranial Cervical ganglion then “hitch-a-ride” with the major blood vessels of the head to supply visceral structures of the head: ___
smooth muscles of the Iris (pupillary dilators), sweat glands, salivary glands, arrector pili muscles, and major blood vessels
CN 1
olfactory (sensory only)
special sensory information (Smell) to brain.
B.Sensory receptor cell bodies are located in Olfactory mucosa of ethmoidal labyrinth.
C.Their axons pass through the cribriform plate and connect with neurons in the Olfactory bulb of the brain.
D.Cannot see the olfactory nerve fibers grossly- they are small and unmyelinated.
E.Clinically, the olfactory nerve fibers can be damaged by head trauma leading to Anosmia. However, olfactory nerves can replace themselves.
Sensory receptor cell bodies for the olfactory nerve are located in ___
Olfactory mucosa of ethmoidal labyrinth.
the axons of the olfactory nerve pass through the ___
cribriform plate
CN 2
optic nerve (prechiasmatic optic tract) (sensory)
optic canal
A.special sensory: visual
B.The “optic nerve” originates from retinal ganglion cells, which are derived from the brain’s optic vesicle and not from the neural crest.
C. Can not repair itself
D.The ganglion cell axons in the “optic nerve” are not the axons of the visual sensory receptor neurons. The ganglion cells collect visual information from the rods and cones of the retina via the bipolar cells. The rods and cones which are the visual sensory receptor neurons project their axons to the brain through the Optic canal of the skull.
The ganglion cell axons in the “optic nerve” are not the axons of the visual sensory receptor neurons. The ganglion cells collect visual information from the rods and cones of the retina via the ___. The rods and cones which are the visual sensory receptor neurons project their axons to the brain through the Optic canal of the skull.
bipolar cells
CN 3
oculomotor (motor) orbital fissure
A.Is Motor only: Somatic efferents (SE) and Visceral efferents (VE).
B.SE fibers exit the skull via the Orbital fissure and innervate the following extraocular muscles: dorsal rectus, medial rectus, ventral rectus, and ventral oblique and the levator palpebrae superioris.
D.VE fibers are part of the Cranial subdivision of the Parasympathetic (Craniosacral) Division of the Autonomic Nervous System.
E.The preganglionic VE nerve fibers of the oculomotor nerve synapse on postganglionic neurons in the Ciliary ganglion (a “Head” ganglion), which in turn send their postganglionic axons into the eye to innervate pupillary sphincter muscles of the Iris and Ciliary body muscles.
F.When stimulated the sphincter muscles of the Iris contract and cause pupillary constriction (miosis).
G.The Ciliary body muscles when stimulated cause the lens to become more convex (rounder), shortening the focal length, and accommodating for close-up vision.
H.Sympathetic fibers from the Cranial Cervical ganglion innervate pupillary dilator muscles of the iris and when stimulated dilate the pupil.
parasympathetic will cause the pupil to __
sphincter muscles of the Iris contract and cause pupillary constriction (meiosis).
sympathetic innervation of the oculomotor will cause the pupil to ___
A.Sympathetic fibers from the Cranial Cervical ganglion innervate pupillary dilator muscles of the iris and when stimulated dilate the pupil.
The VE fibers of CN3 will cause the ciliary body to do what ___
The Ciliary body muscles when stimulated cause the lens to become more convex (rounder), shortening the focal length, and accommodating for close-up vision.
CN 4
trochlear (motor) orbital fissure
A.Is Motor only: only Somatic efferent (SE) fibers.
B.smallest
C.innervates the dorsal oblique muscle.
D.passes through the cartilagenous trochlea (pulley)
E.Only cranial nerve originating from the dorsal surface of the brain.
CN 4 contains what kinds of fiber
trochlear
motor only
SE fibers only to the dorsal oblique eye muscle
CN3 contains what kind of fibers
oculomotor
motor only
SE and VE
SE to eye muscles
VE: to eye: parasympathetic: pupil contracts and close up vision
sympathetic: pupil dilate
what kind of nerve fibers does CN 1 have
olfactory
sensory only
special sensory for smell
what kind of nerve fibers does CN2 have?
optic nerve
special sensory only: sight
CN 5
trigeminal (motor and sensory)
Ophthalmic: oribital fissure (SA only-sensory)
Maxillary: rostral alar foramen (SA only-sensory)
Mandibular: oval foramen (SA and SE- motor and sensory)
SA: sensory from face and head
SE: mastication muscles: masseter, temporalis and rostral belly of the digastricus
CN 5 has what type of fibers?
both sensory and motor
SA: sensory from face and head (all three branches- opthalmic, maxillary and mandibular)
SE: mastication muscles: masseter, temporalis and rostral belly of the digastricus (only mandibular has motor)
branches of trigeminal
Ophthalmic= Orbital fissure
Maxillary= Rostral Alar foramen→ maxillary formamen → infraorbital nerve → infraorbital formamen
Mandibular= Oval foramen, auriculotemporal, inferior alveolar, lingual
CN 6
abducent, orbital fissure (motor)
motor only: SE only
SE axons exit the skull via the Orbital fissure and innervate lateral rectus and retractor bulbi muscles of the eye.
what kind of fibers does CN6 have?
motor only: SE only to retractor bulbi and lateral rectus
CN7
facial (both: motor and sensory) (stylomastoid formamen)
branches: auriculopalpebral, dorsal buccal and ventral buccal
B. fiber types: SE; VE; SA; and Taste.
C.Motor axons (SE) innervate muscles of facial expression (branchial arch origins), e.g. Orbicularis Oris, Orbicularis Oculi, and caudal belly of Digastricus and some superficial muscles of the ear.
D. VE axons contain Parasympathetic fibers (Cranial subdivision of the Cranial-sacral part of the Autonomic Nervous System):
- innervate Lacrimal, Palatine, and Nasal glands for lacrimation and mucosal secretion via the pterygopalatine ganglion.
- the Mandibular and Sublingual Salivary glands for salivation. via the mandibular and sublingual ganglia, respectively.
H. Sympathetic innervation to the above glands is via the sympathetic trunk, vagosympathetic trunk, and cranial cervical ganglia post-ganglionic axons. Sympathetic innervation of the above glands is generally antagonistic to the parasympathetic innervation.
I. SA axons provide sensory innervation to the inside surface of the pinna of the ear and are connected to pseudounipolar neurons in a sensory ganglion.
J. Taste fibers originate from taste receptors on the taste buds of the rostral 2/3rds of the tongue. Taste (gustatory) receptor cells connect to pseudounipolar neurons in a sensory ganglion that conduct taste information to the brain.
what kind of fibers does CN7 have?
facial (both)
SE, VE, SA, taste
SE: muscles of facial expression
VE: parasympathetic and sympathetic: tear, mucous and salivary glands (lacrimal, palatine, nasal, mandibular and sublingual)
SA: sensory from the inside of ear
taste: rostral ⅔ of the tongue
what CN innervates the muscles of facial expression
CN7 facial
Orbicularis Oris, Orbicularis Oculi, and caudal belly of Digastricus and some superficial muscles of the ear
VE axons from CN7 to the ___ are via pterygopalatine ganglion.
lacrimal, palatine, and nasal glands
VE axons from CN7 to ___ are via the mandibular and sublingual ganglion
mandibular and sublingual
Sympathetic innervation from CN ___ to the Lacrimal, Palatine, Nasal, Mandibular and Sublingual Salivary glands is via the ___
CN7 facial
sympathetic trunk, vagosympathetic trunk, and cranial cervical ganglia post-ganglionic axons.
branches of CN7
facial: auriculopalpebral, dorsal buccal, ventral buccal
CN8
vestibulocochlear (sensory only)
special sensory: hearing and balance
A.The two different bundles of axons for auditory and vestibular senses are fused into one gross nerve.
B.Will not see this nerve grossly in this course because its two sensory organs, the Cochlea (Hearing) and SemiCircular Canals (Balance) are contained within one of the densest bones of the skull, the petrous part of the temporal bone.
what kind of fibers does CN 8 have
vestibulocochlear
sensory only
special sensory: hearing and balance
CN 9
glossopharyngeal (jugular → tympano-occipital fissure) (both- motor and sensory)
B. fiber types: SA,VA,SE, VE, and Taste.
C. SA axons: sensory innervation to skin of the external auditory meatus/canal.
D. VA axons: mucosa of caudal tongue and pharynx (involved with the gag reflex) and the carotid sinus/carotid body for, respectively, blood pressure and chemoreception (pO2 and pCO2).
E. SE axons: muscles of pharynx and soft palate for swallowing. These muscles are branchiomeric in origin.
F. VE axons of the Cranial subdivision of the Parasympathetic (Cranio-sacral) Division of the Autonomic Nervous System innervate the Parotid and Zygomatic salivary glands to produce salivary secretion.
G. sympathetic innervation to parotid and zygomatic salivary glands
H.Taste fibers: caudal 1/3rd of the tongue.
what kind of fibers does CN 9 have
glossopharyngeal (jugular → tympano-occipital fissure) (both- motor and sensory)
B. fiber types: SA,VA,SE, VE, and Taste.
C. SA axons: sensory innervation to skin of the external auditory meatus/canal.
D. VA axons: mucosa of caudal tongue and pharynx (involved with the gag reflex) and the carotid sinus/carotid body for, respectively, blood pressure and chemoreception (pO2 and pCO2).
E. SE axons: muscles of pharynx and soft palate for swallowing.
F. VE axons: parasympathetic and sympathetic: Parotid and Zygomatic salivary
H.Taste fibers: caudal 1/3rd of the tongue.
CN 10
vagus (jugular → tympano-occipital fissure) (both- 80% are sensory)
fiber types: SA,VA,SE,VE, and Taste.
E. SA axons: skin of the auditory canal.
F. VA axons: pharynx, larynx, trachea, esophagus, and thoracic and abdominal viscera and have their pseudounipolar neurons located within the Distal Vagal sensory ganglion.
I. SE axons: muscles of the pharynx, larynx, and esophagus for swallowing, respiration, and vocalization.
J. VE axons: Parasympathetic to thoracic and abdominal viscera.
K. Taste receptor for the pharynx and epiglottis and connect with pseudounipolar neurons in a sensory ganglion that conducts taste information to the brain.
what kind of fibers does CN10 have
fiber types: SA,VA,SE,VE, and Taste.
E. SA axons: skin of the auditory canal.
F. VA axons: pharynx, larynx, trachea, esophagus, and thoracic and abdominal viscera
I. SE axons: muscles of the pharynx, larynx, and esophagus for swallowing, respiration, and vocalization.
J. VE axons: Parasympathetic to thoracic and abdominal viscera.
K. Taste receptor for the pharynx and epiglottis
CN 11
accessory (foramen magnum→ tympano-occipital fissure) (motor)
motor: SE only
B. SE axons: trapezius, omotransversarius, cleidocervicalis, and sternocephalicus.
C. Weird route: Its fibers exit the first five or six cervical spinal cord segments midway between the dorsal and ventral root attachments of these cervical spinal cord segments. The exiting spinal accessory nerve fibers then ascend along the lateral surface of the spinal cord as the spinal accessory nerve, passing through the foramen magnum. The spinal accessory nerve continues to ascend to where the vagus nerve attaches to the brain. The accessory nerve then turns laterally and exits the Jugular foramen and Tympano-Occipital fissure of the skull along with the vagus and glossopharyngeal nerves. The spinal accessory nerve then travels down the neck adjacent to the omotransversarius muscle to innervate the aforementioned neck and forelimb muscles
what kinds of fibers does CN11 have
accessory
motor only: SE only: (BOTS) trapezius, omotransversarius, cleidocervicalis, and sternocephalicus.
CN 12
hypoglossal nerve (hypoglossal canal) motor
SE only: tongue muscles assisting swallowing, mastication, and vocalization
CN12 has what types of fibers
hypoglossal
SE only: tongue muscles assisting swallowing, mastication, and vocalization
Cn3 goes through which head ganglion to what
cililary ganglion
pupillary sphincter and ciliary body muscles
(parasympathetic)
CN7 goes through which head ganglion
two:
pterygopalpatine ganglion: lacrimal, nasal and palatine glands
sublingual and mandibular ganglion: mandibular and sublingual salivary gland
parasympathetic
CN 9 goes through which head ganglion
otic ganglion: parotid and zygomatic salivary glands
parasympathetic
5 head ganglion
parasympathetic
sublingual missing
facial nerve with hitch a ride with ___ to get to mandibular and sublingual salivary glands
Facial nerve → chorda tympani (branch of Facial nerve) → lingual nerve (branch of Mandibular branch of Trigeminal nerve) → Ramus communicans → Mandibular and Sublingual ganglia → Mandibular and Sublingual Salivary glands, respectively.
facial nerve with hitch a ride with ___ to get to lacrimal
Facial nerve → major petrosal nerve → nerve of pterygoid canal → Pterygopalatine ganglion → zygomatic nerve (branch of Maxillary branch of trigeminal nerve) → lacrimal nerve (branch of Ophthalmic branch of Trigeminal nerve) → Lacrimal gland.
facial nerve will hitch as ride on __ to get to palatine and caudal nasal mucosal glands
Facial nerve → major petrosal nerve → nerve of pterygoid canal → Pterygopalatine ganglion → Pterygopalatine nerve (a branch of the Maxillary branch of Trigeminal nerve)→ major palatine nerve, minor palatine nerve, accessory palatine nerve, and caudal nasal nerve → Palatine and Caudal Nasal mucosal glands
Facial nerve will hitch a ride on __ to get to rostral ⅔ of tongue
Lingual nerve (branch of Mandibular branch of Trigeminal nerve) → chorda tympani (branch of Facial nerve) → geniculate ganglion (sensory neuron cell bodies) → Facial nerve → “Taste” nucleus of caudal brainstem (Nucleus Solitarius).
CN9 will hitch a ride on ___ to get to the parotid salivary gland
Glossopharyngeal nerve → Otic ganglion → Auriculotemporal nerve (branch of Mandibular branch of Trigeminal nerve) → Parotid Salivary gland.
CN9 will hitch a ride on ___ to get to the zygomatic salivary gland
Glossopharyngeal nerve → Otic ganglion → buccalis nerve (branch of Mandibular branch of Trigeminal nerve) → Zygomatic Salivary gland.
function of CN1
smell
function of CN5
function of CN6
function of CN7
function of CN8
function of CN9
function of CN10
function of CN11
function of CN12
