Peripheral Nervous System Flashcards
Parts of Peripheral Nervous System (PNS)
- cranial nerves
- spinal nerves
- Autonomic nervous system
- sympathetic branch
- parasympathetic branch
The PNS is a collection of nerves outside the _____ ______ and skull
spinal column and skull
nervous system that carries sensory and motor impulses back and forth fromt he brain to various parts of the body
PERIPHERAL NERVOUS SYSTEM
Three types of nerves in the PNS
- Cranial (12)
- Spinal (31 pairs)
- Autonomic
Cranial Nerves
- On Occasion Our Trusty Truck Acts Funny Very Good Vehicle Anyhow
- I - Olfactory
- II - Optic
- III - Oculomotor
- IV - Trochlear
- V - Trigeminal
- VI - Abducens
- VII - Facial
- VIII - Vestibulocochlear
- IX Glossopharyngeal
- X - Vagus
- XI - Spinal accessory
- XII - Hypoglossal
Cranial Nerve I
Olfactory
Smell (sensory)
CN II
Optic
Vision (sensory)
CN III
Oculomotor
Eye movement (motor)
CN IV
Trochlear
Eye movement (motor)
CN V
Trigeminal
Face (sensory); Jaw (motor)
CN VI
Abducens
Eye movement (motor)
CN VII
Facial
Tongue (sensory); face (motor)
CN VIII
Vestibulocochlear
Hearing and balance (sensory)
CN IX
Glossopharyngeal
Tongue and pharynx (sensory); pharynx only (motor)
CN X
Vagus
Larynx, respiratory, cardiac and gastrointestinal systems
(sensory and motor)
CN XI
Spinal accessory
Shoulder, arm, and throat movements (motor)
CN XII
Hypoglossal
Mostly tongue movement (motor)
Which Cranial Nerves are involved with speech, language and hearing?
V, VII, XII
Vagus, Facial, Hypoglossal
3 sensory branches of CN V
- Opthalmic - sensory branches for nose, eyes, forehead
- Maxillary - sensory branches from nose, upperlip, maxilla, upper cheek, upper teeth, maxillary sinus, nasopharynx, palate
- Mandibular - from mandible, lower teeth, lower lip, tongue, part of the cheeck and part of external ear
- transmits tactile, pain, and temperature but not taste stimuli from anterior two-thirds of tongue
- Also has motor fibers that innervate various jaw muscles, including temporalis, lateral & medial pterygoids, masseter, tensor veli palatini, tensor tympani, mylohyoid, anterior belly of digastric
Sign of unilateral upper motor neuron lesions to cranial nerve V
- minimally impacts motor function because CN V is bilaterally innervated
- will cause jaw to deviate towards affected side when mouth is closed
Bilateral damage to cranial nerve V
- inability to close mouth
- difficulty chewing
- Trigeminal neuralgia - sharp pain in facial area
CN V is a motor nerve
False
its a motor and sensory nerve (mixed nerve)
CN VII is a mixed nerve
True
Sensory fibers are responsible for taste sensations on the anterior two thirds of the tongue
Motor fibers innervate muscles important to facial expression and speech
Unilateral upper motor neuron lesion to CN VII will only paralyze the lower face
T/F
TRUE
the upper portion of the face is bilaterally innervated so unilateral UMN damage would result in paralysis only to lower face
Inability to move the upper and lower face resulting in mask-like appearance with miniml or no facial expression indicates damage to what cranial nerve?
Cranial Nerve VII - Facial
indicates bilateral damage to facial nerve
When there is a sign of unilateral damage to the facial nerve?
A smile drawn to the undamaged side
Glossopharngeal Nerve CN IX is a mixed nerve
T/F
True
it has sensory, motor, and autonomic components
Functions of sensory component of CN IX glossopharyngeal
- assists in processing taste sensations from the posterior third of tongue
- provides sensation for tympanic cavity, ear canal, eustachian tube, faucial pillars, tonsils, soft palate, and pharynx
Functions of motor fibers of glossopharyngeal nerve CN IX
- innervates the stylopharyngeus - a muscle that raises and dilates the pharynx.
- May innervate the superior pharyngeal constrictor
- Supplies motor fibers to pharyngeal plexus along with CNX that innervates the upper pharyngeal constrictor muscles.
Signs of lesions in glossopharyngeal nerve
- difficulty in swallowing
- unilateral loss of gag reflex
- loss of taste and sensation from posterior third of tongue
CN X Vagus is a mixed nerve
T/F
True
- contains motor, sensory and autonomic fibers
- called a wandering “vagus” nerve cause it extends from neck into chest and stomach
- Motor fibers supply the digestive system, heart, lungs, pharynx, and larynx
- Sensory- conveys info from digestive system, heart, trachea and bronchi, lower pharynx, larynx, and epiglottis.
- transmits pain, touch and temperature sense from skin covering the tympanic membrane and ear canal.
- Includes RLN and SLN, pharyngeal branch
Branch of the vagus nerve that regulates the intrinsic muscles of the larynx, excluding the cricothyroid; The left side courses uner the heart and back up to the esophagus, trachea and larynx
Recurrent Laryngeal Nerve (RLN)
Damage to this branch of the vagus nerve during thyroid surgery can result in total or partial paralysis fo the vocal folds;
Damage to its left branch during cardiac surgery can result in paresis or paralysis of the left vocal fold
Recurrent Laryngeal Nerve
(RLN)
The branch of the vagus nerve that supplies the pharyngeal constrictors and all the muscles of the velum except the tensor veli palatini;
It also transmits sensory information from the base of tongue and pharynx
Pharyngeal Branch
Branch of vagus nerve that is divided into internal (sensory) and external (motor) branches
SUPERIOR LARYNGEAL NERVE (SLN)
- Internal - receives sensory information from the larynx above the vocal folds
- External - innervates the cricothyroid muscle; damage to this branch results in inability to change pitch
Signs of Damage to Vagus Nerve
Due to its extensive course, damage to vagus nerve includes a variety of sequelae
- difficulty swallowing
- paralysis of velum (resulting in nasality issues)
- voice problems (aphonia, hoarseness, breathiness, roughness) if RLN is damaged
Motor Nerve that runs under the tongue
CN XII Hypoglossal Nerve
Cranial nerve that supplies all extrinsic tongue muscles except for palatoglossus muscle; and supplies all intrinsic muscles of tongue.
CN XII Hypoglossal
Signs of damage to CN XII
Lesions to hypoglossal nerve can result in :
- tongue paralysis
- diminished intelligibility
- swallowing problems
