The Cranial Nerves Chapter 6 Flashcards
Where are CN?
PNS
What do CN do?
- provides sensory/ motor information to structures in head and neck
How many CN are there?
12
CN I ?
Olfactory
CN ll ?
Optic
CN lll ?
Oculomotor
CN lV ?
Trochlear
CN V?
Trigeminal
CN Vl ?
Abducens
CN Vll ?
Facial
CN Vlll ?
Vestibulocochlear
CN lX ?
Glossopharyngeal
CN X ?
Vagus
CN Xl ?
Accessory
CN Xll?
Hypoglossal
Where is CN 6, 7, 8 located?
in between pons and medulla
What nerve is in the pons?
- Trigeminal
Where are CN 9,10,11, 12 located?
medulla
What are 3 ways to define CN?
- Function
- Area of service
- Type of Fiber
What are the 2 types of functions?
- General
2. Special
What does General Function mean ?
- Motor and sensory or both
2. Sensory information provides motor info
What does special functions mean?
- never conveying special senses
- no motor
- smell CN l , auditory CN Vlll , vision CN ll
CN l / CN ll / CN Vlll are ?
!. Special senses and sensory senses
What are the 2 areas of service for CN ?
- Somatic - functions were we have control
2. Visceral - functions that we don’t have control
What are the 2 types of fibers in CN ?
1 Afferent - sensory
2. efferent - motor
- could be both*
Afferent connection ?
arrives
Efferent connection ?
exist
Olfactory CN ?
- CN l
- Only nerve fibers / projection that don’t go to the thalamus for further processing
- Sensory / special
- Afferent - smell
Olfactory CN location ?
Level at Cerebrum Brain
Olfactory CN pathway ?
- Initial receptors ( BIPOLAR ) of smell are in the nasal cavity.
- Bipolar neurons take smell and assist on to the second neurons—— Olfactory bulb
- Olfactory bulb passes though the ethmoid bone ——-cribaform palate
- through the cribaform palate holes projections / fibers of the nerve passes through to reach the cortex
Where do the Olfactory CN end up in the cortex ?
- temporal lobe
2. Lombax system
Lombax system ?
- Memory and emotion
Optic Nerve ?
- CN ll
- Special / Sensory
- Afferent / Vision
What is the Optic Nerve Pathway ?
- respecters of the retina
- the nerve comes out the most posterior part of the eyes ( nasal or temporal )
- travels until optic Chiasm - nasal crosses and temporal continues to go down
- some of the nerves will travel to the superior colliculus and some will go to the LGN Thalamus
- continues to the cortex —- occipital lob
what is optic chiasm ?
Crossing for nasal fibers of the Optic Nerve
Where is the Optic Nerve ?
Level at the cerebrum brain
Oculomotor Nerve ?
CN lll
Movement of Eyes
What are the 2 Main fibers of Oculomotor Nerve ?
- GVE – constriction of pupil
- GSE – Holding eyelid open
No Sensory !!
What are 3 pathologies of Oculomotor Nerve ?
- Ptosis - eyelids droopy
- strabismus - eyes crossing
- diplopia - seeing double
Which Nerve Nuclei is located the pons?
5
n/a
n/a
Trochlear nerve ?
- Movement of the eyes
- GSE - Motor
- CN lV
what small muscle does Trochlear nerve innervate?
- superior oblique musclé of the eye
2. downward movement
Trochlear nerve is the ONLY CN that exist where?
from the dorsal aspect
Trigeminal ?
- CN V
- Largest Nerve
- Has 3 major branches
- Sensory touch, pain, temp, and vibration for face and mouth —- GSA
- motor chewing ——- GVE
what are the 3 major branches of Trigeminal ?
- Ophthalmic
- maxillary
- mandibular
Trigeminal CN Ophthalmic branch ?
- sensory
- eye / forehead area
- passes through superior fissure
Trigeminal CN maxillary branch ?
- Sensory
- Maxilla skin
- foramen rotundum
Trigeminal CN mandibular branch ?
- sensory / motor
- anterior 2/3 of the tongue —- sensory
- mandible - chewing muscles – motor
- formen ovale
Abducens ?
- CN Vl
- Motor GSE
- controls movement of a signal muscle
Abducens muscle?
- Lateral rectus muscle of eye
Facial ?
- CN Vll
- Morot and Sensory
- problems could be bells palsy
What are the motor of facial?
- Muscle of facial expressions
2. chewing/ speaking
What are the sensory of facial CN?
- taste anterior 2/3 of the tongue
What is bells palsy ?
- weakness in facial muscle
- could be because of viral infection or not proper intervention of the facial Nerve
- could be resolved in 4 - 6 months
What nerves go through the internal acoustic meatus?
CN 7
CN 8
Vestibulocochlear ?
- CN 8
- two branches —- vestibular and cochlear
- sensory
- deals with balance and audio at the same time
Auditory Nerve pathway in Vestibulocochlear CN ?
- stimulating the hair cells in the inner ear
- goes to the spinal ganglion - cochlea
- goes to the medulla
- goes to the pons—- superior olivary complex
- goes to mid brain — inferior colliculus
- MGN - thalamus
- Auditory cortex
Glossopharyngeal ?
- CN 9
2. sensory and motor
Sensory in the Glossopharyngeal CN? ( 4 items )
- posterior 1/3 tongue
- tonsils
- pharynx
- middle ear
Motor ( parasympathetic fibers ) in the Glossopharyngeal CN? ( 2 items)
- Gag reflux
2. stylopharyngeus muscle innervation
stylopharyngeus muscle innervation ?
elevates the larynx
What nerves go through the Jugular foramen ?
9, 10 ,11
Vagus CN?
- Important for voice
- lateral side of medulla
- afferent , efferent , somatic , visceral
n/a
n/a
What are the 2 main branches of motor in vagus CN?
- pharyngeal
2. Laryngeal
Pharyngeal Vagus CN ?
- Superior
- Middel
- Inferior pharyngeal constrictors
- levator veli palatinl
levator veli palatinl?
- elevating volume
2. doesn’t work right could cause nasal speech / regurgitation
Laryngeal Vagus CN ?
- muscle of the larynx
- sensory above and below the larynx
- not feeling anything going into the air way
Motor Vagus CN ?
1. pain from pharynx larynx esophagus abdominal
Accessory ?
CN 11
2 branches spinal and cranial
provides motor innervation 2 muscles
GSE nerve
in the Accessory CN what two muscles are innervated?
- sternocleidomastoid muscle
2. Upper part of trapezius muscle
Hypoglossal Nerve ?
- GSE motor
- Motor fibers to all muscle of the tongue EXEPT PALATOGLOSSUS — innervated by vagus
- if not innervated could cause articulation problems
