Exam 3 - CNs Flashcards
cranial nerves are part of the PNS or CNS?
PNS
CNs emerge from? which numbers emerge from where?
- cortex (I and II)
- BS (III-XII)
CNs are vulnerable to ___
- examples
trauma
- twisting, tearing, shearing of the axon, degradation of myelin
what are the three types of CNs?
- sensory only
- motor only
- mixed (sensory and motor)
sensory only CNs use ____ for ____
peripheral ganglia for SENSORY INPUT
sensory only CNs use ____ for ____
peripheral ganglia for SENSORY INPUT
motor only CNs innervate? (2)
- use?
- Somatic innervates skeletal musicle
- autonomic (parasymp, innervates glands)
- peripheral ganglia for ANS INNERVATION
Afferent Special cranial nerves get info from?
- two divisions info comes from? type of info from each?
- HEAD only
- Somatic: sight, hearing, balance
- Autonomic: smell, taste
Afferent General CNs get info from?
- two divisions info comes from? type of info form each?
- everywhere except head
- Somatic: pain, temp, and mechanoreceptor info from skin/joints
- Autonomic: receptors in organs and glands
Efferent Special CNs get info from?
- info comes from? type of info?
HEAD ONLY
- Somatic ONLY: move facial muscles for facial expression, phonation, chewing, swallowing
Efferent General CNs get info from?
- two divisions info comes from? type of info from each?
- everywhere except head
- Somatic: innervate skeletal muscle, move eyes, move extrinsic tongue
- Autonomic: innervate organs, glands
Efferent General CNs get info from?
- two divisions info comes from? type of info from each?
- everywhere except head
- Somatic: innervate skeletal muscle, move eyes, move extrinsic tongue
- Autonomic: innervate organs, glands
which cranial glands are impacted by the parasympathetic system
3, 7, 9, 10
What are the AFFERENT parasympathetic cranial nerves
- list their functions
- CN IX - Glossophyaryngeal: sensation of taste, sensation of BP from carotid sinus & body
- CN X - Vagus: assists in decrease HR & BP, input from viscera in thorax/abdomen
What are the EFFERENT parasympathetic cranial nerves
- list their functions
- CN III, Oculomotor: pupil constriction/dilation, convexity of lens
- CN VII, Facial: salivary glands, lacrimal glands
- CN IX: Glossopharyngeal: parotid gland (salivation)
- CN X, Vagus: Glands & mucous membranes, pharynx/larynx/neck/thorax
list the cranial nerves in order
- Olfactory
- Optic
- Oculomotor
- Trochelar
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear
- Glossopharyngeal
- Vagus
- Accessory
- Hypoglossal
tell whether each number of cranial nerve is sensory, mixed, or both
- Sensory
- Sensory
- Motor
- Motor
- Both
- Motor
- Both
- Sensory
- Both
- Both
- Motor
- Motor
study picture on slide 6 - know the location of all the CNs
STUDY!!!
what are the Special Sensory Cranial Nerves? what does this mean? general function of these 3?
- I, Olfactory
- II, Optic
- VIII, Acoustic-Vestibulocochlear
- **They ONLY provide sensory input and it’s ONLY from the head
- **To convert some sort of energy into a neural impulse
What’s the Olfactory nerve do?
- what’s the pathway?
- converts chemical energy to smell
1. Receptor cells in nasal cavity
2. Nerve endings in mucosoul membrane
3. Nerve endings travel through skull to olfactory bulbs on the ventral aspect of frontal lobe
4. Terminate in temporal lobe
5. DOES NOT cross
the olfactory nerve goes directly into ____, bypassing ____
the limbic system
- the thalamus
the olfactory nerve emerges from ____, so?
the cerebrum, it’s TECHNICALLY in the CNS
the olfactory nerve emerges from ____, so?
the cerebrum, it’s TECHNICALLY in the CNS
VISION itself is a function of what CN?
CN II, Optic
what does CN II do? info gets sent where?
- converts light energy to a neural impulse
- thalamus to occipital
interesting fact about optic nerve?
it’s technically in CNS
what’s the more specific pathway of the optic nerve?
- receptor cells in lining of retina (rods, cones)
- To optic nerves (leaves eye socket, joints at OPTIC CHIASM)
- now are optic tracts
- ipsi and contralateral, supplying ino to both hemisphere - to thalamus (synapse with LGN)
- to occipital lobes (each lobe receives input form each eye)
what’s the pathway for CN VIII Acoustic/Cochlear Branch?
- hair cells in cochlea
- VIII nerve, cochlear division
- Brainstem (midbrain) - synapse on multiple nuclei in the cochlear nuclear complex
- Thalamus (MGN)
- Internal capsule
- Projection fibers
- temporal lobe
what’s CN VIII Vestibular Branch do? (3)
- ID resting head position
- ID change in head position
- Work w/ proprioception, vision
what’s the pathway for CN VIII vestibular brance?
- Internal ear to CNS
- Semicircular canals
- Vestibular ganglion
- Brainstem, between pons & medulla
- to synapse on vestibular nuclei
- to cerebellum OR to motor neurons for eyes OR to motor neurons for head/neck/limb movements
what’s the pathway for CN VIII vestibular brance?
- Internal ear to CNS
- Semicircular canals
- Vestibular ganglion
- Brainstem, between pons & medulla
- to synapse on vestibular nuclei
- to cerebellum OR to motor neurons for eyes OR to motor neurons for head/neck/limb movements
what are the MOTOR ONLY Cranial nerves? which three have a common function?
III Oculomotor
IV Trochlear
VI Abducens *****THESE 3 MOVE THE EYE
XI (Spinal) Accessory
XII Hypoglossal
Explain the main roles of the 3 CNs that move the eye
- Oculomotor (III): UP/DOWN, constricts PUPIL (ANS) *most eye movement, open eyelid
- Trochlear (IV): IN & DOWN
- Abducens (VI): OUT (lateral)
Two main purposes of the Oculomotor merve
1) Somatic (skeletal):
- move eye up/down
- open eyelid
2) Autonomic: pupil constriction
motor pathway of oculomotor nerve (probably don’t really need to know in depth)
- precentral gyrus to BS (midbrain)
- Synapse on 2 different nuclei (somatic & ANS)
- Becomes CN III (PNS)
- Leaves BS towards eye
- 2 branches (superior & inferior)
PROBLEMS with the oculomotor nerve?
- DROOPY look
- can’t open eye or eyelid
- can’t constrict pupil
- can’t look up/in
- can’t look down and out
Main purposes of trochlear nerve (2)
- move eye down and in
- maintain vertical perspective when head moves
motor pathway of trochlear nerve
- precentral gyrus to midbrain/brainstem
- synapses on trochlear nucleus (LMN)
- becomes CN IV (PNS) and exits dorsal BS
- Curves around to anterior aspect of BS
- wiggles around through many cerebral arteries
2 fun facts about trochlear CN
- smallest & longest CN
- only one coming around from posterior BS
problems with trochlear nerve?
- can’t look down
- eye stays too far up
- have to tilt my head down
- get double vision
- can’t look in towards own nose
abducens main purpose
- LATERAL eye movement (out/away from midline)
motor pathway for abducens
- precentral gyrus to BS (pons)
- synapse at LMN in pons (just below 4th ventricle)
- Is now CN VI
- Emerges and travels to eye
problems with abducens
- drifts to midline
- stuck looking at nose = crossed appearance
explain the two “components” of the spinal accessory nerve. What do each of these “components” do?
- cranial root: works w/ Vagus
- elevates soft palate - spinal root: controls trapezius and sternocleiodmastoid
- turn/tilt head
- raise/shrug shoulders
motor pathway for cranial root of spinal accessory CN (probably don’t need to know this)
- precentral gyrus
- medulla
- synapses with nucleus in BS
- travels along with vagus
motor pathway for spinal root of accessory CN (probably don’t need to know this)
- precentral gyrus
- medulla
- synapses w/ nucleus in C1 (SC)
- travels upward, enters skull through foramen magnum
- travels around toward carotid; joins up with cranial root
- hits the sternocleiodomastoid, then down/around to trapeziue
MAIN things to remember about spinal accessory nerve
MOTOR ONLY
- cranial root - elevate SOFT PALATE
- spinal root - trapezius and sterno. = turn/tilt head & shrug shoulders
hypoglossal nerve functions are important for?
speech, moving food around in mouth, swallowing
3 main things hypoglassal nerve does? (list functions under)
- INTRINSIC tongue muscles
- shorten, flatten, elongate
- elevate tongue - EXTRINSIC tongue muscles
- protrude, retract, depress - elevates HYOID
- helps w/ phonation
hypoglassal is ____ innervated
unilaterally
motor pathway of the hypoglossal nerve
- from precentral gyrus to BS
- synapses w/ hypoglossal nucleus
- exits BS and winds around Vagus
- winds between carotid artery & jugular vein
- arrives at tongue
problems with hypoglossal nerve?
- a BIG deal - can’t speak, chew, or move food to the back of the mouth, where it needs to be in order to trigger a swallow
list the MIXED cranial nerves (and anything especially significant about them)
- V Trigeminal (some motor, MOSTLY SENSORY)
- VII Facial (MOSTLY MOTOR, some sensory
- IX Glosspharyngeal
- X Vagus (long, winding)
How many branches does the trigeminal nerve have?
- list the branches, tell whether they’re sensory/motor/mixed
THREE
- V1, Opthalmic (sensory only)
- V2, Maxillary (sensory only
- V3, Mandibulary (mixed)
know picture on slide 28
study
the opthalmic branch of the trigeminal nerve does what?
- It’s sensory only, and it receives pain, temp, touch, and proprioception info from forehead/anterior scalp/eye/nose/sinuses
the maxillary brance of the trigeminal nerve does what?
- it’s sensory only, and it receives pain, temp, touch, and proprioception info from temples/upper cheeks/lower eye/upper lips and gums/teeth/palates
the SESNORY function of the mandibular branch of the trigeminal nevrve does what?
- receives pain, temp, touch, and proprioception from the sides of scalp/external ear/lower gum/anterior 2/3 tongue
the MOTOR function of the mandibular branch of the trigeminal nerve does what?
- chewing, soft palate elevation, eardrum protection
motor pathway of trigeminal nerve
- Precentral gyrus to BS (pons)
- synapses with LMN
- fibers exit skull & join up w/ mandibular branch of nerve
- innervate muscles of mastication
- elevates soft palate
- dampens sounds of chewing
look over pic on slide 30
look it over
what’s trigeminal neuralgia?
when this nerve is overactive, and it results in PAIN
The Facial nerve is very complicated. It has multiple branches:
- some are ____
- some are ____
- within skull
- outside skull
The Facial nerve has mixed jobs. Explain what this means.
- Mostly motor - both somatic and autonomic
2. Some sensory to autonomc
facial nerve runs in close proximity to what other nerve?
8th nerve
surgical procedures can often accidentally cut which neves? Why?
7 & 8: they’re very close to each other on the face
the EXTERIOR branches of the facial nerve engage in what functions?
MOTOR-SOMATIC
what are the TWO main exterior branches of the facial nerve
- digastric
2. posterior auricular branch
what are the 5 branches of the posterior auricular branch of the facial nerve. list functions (may not need to really know this)
- temporal branch: wrinkle forehead/move scalp
- zygomatic branch: close eyes tightly
- buccal branch: smile/snarl/elevate upper lip/cheeks
- mandibular branch: depress lower lip; chin
- cervical branch: frown; wrinkle neck
list the INTERIOR branches of the facial nerve with their functiosn
- parasympathetic sensory
- chorda tympani branch/taste from anterior 2/3 tongue - motor somatic
- innervates stapedius (controls excess sound) - motor autonomic
- parasympathetic
- salivary glands
- lacrimal glands
list the divisions of the glossopharyngeal nerve with functions (4=3)
- Sensory - somatic
- sensation from tonsils, pharynx, middle ear
- sensation from posterior pharynx to trigger GAG REFLEX
- taste from posterior 1/3 of tongue - Motor - somatic
- stylopharyngeus muscle
- helps elevate pharynx during swallowing, speech - Motor - parasympathetic
- supplies parotid gland
- SALIVATION
The vagus nerve has both ____ and ____ SOMATIC functions as well as both ____ and _____ AUTONOMIC functions
- motor & sensory
- motor & sensory
what are the MOTOR-Somatic branches of the vagus neve, and what are their functions?
- pharyngeal branch
- retract/elevate soft palate
- pharyngeal constriction - laryngeal branch (superior)
- more pharyngeal constriction
- EXTRINSIC laryngeal muscles
- cricothyroid (phonation/goicing, glottal coup_ - Laryngeal branch (recurrent)
- INTRINSIC laryngeal muscles
- elevates during phonation
- elevates during swallowing
what are the Sensory-Somatic functions of the vagus nerve?
- pain, temp, touch larynx, pharynx, and external ear
- contributes to ability to avoid aspirating
Motor-Autonomic functions of vagus nerve
- L recurrent laryngeal nerve
- smooth muscle of ehart
- respiratory system
- digestive system
sensory-autonomic functions of vagus nerve
- mucosal coating of epiglottis, tongue base, larynx
vagal nerve dysfunction?
- under/over active stimulation
- disrupted/impaired digestion
- overactive - cramping, pain
- insufficient heart rate/BP
- implant to stimulate/regulate
look over pics on 40, 41, & 43
look over them
