Lecture 12: Cranial Nerve Lecture + Names Flashcards
I
Olfactory
II
Optic
III
Ocularmotor
IV
Trochlear
V
Trigmenial
VI
Abducens
VII
Facial
VIII
AudioVestibular
IX
Glossopharyngeal
X
Vagus
XI
Spinal Accessory
XII
Hypoglossal
What do nerves III, IV, and VI have to with?
Moving of the eye inside its orbit
What is the biggest nerve?
The Trigeminal nerve
What is the name of CN I?
Olfactory nerve
What type of nerve is the olfactory nerve? (Motor/Sensory)
Pure Sensory
What is the Olfactory nerve (I) responsible for?
Smell
What is the Olfactory Epithelium?
Sensory receptors in the roof of nasal cavity that connect to the Olfactory nerve
What do Olfactory Nerve Filaments do?
Supply Olfactory epithelium
What is the pathway from the Olfactory epithelium?
- Olfactory epithelium
- Olfactory Olfactory nerve
- Olfactory bulb
- Olfactory tract
- 1º Olfactory cortex (temporal lobe)
What does the Thalamus serve as?
A relay station for sensory input
What is the only system to bypass the Thalamus?
The Olfactory system
What does Damage or Disease to the olfactory nerve cause?
Hyposmia and or Anosmia
What is Hyposmia and Anosmia?
Hyposmia is the partial loss of smell and Anosmia is the full loss of smell
What bone do the Olfactory nerves go through?
The Cribriform plate
What are the Special Senses?
- Olfaction
- Vision
- Auditory
- Taste
How does Olfactory sensation work?
Odorants bind to the axons and cause an action potential
Where is the 1º Olfactory cortex found?
In the temporal lobe
What kind of nerve is the Optic nerve (II)? (Motor/Sensory)
Pure sensory
What is the optic nerve responsible for?
Vision
What is the pathway of the Optic Nerve from the eye?
- Axons of ganglion cells
- Optic Nerve
- Optic Chiasm
- Optic Tract
- Lateral Geniculate Nucleus (Thalamus)
- Optic Radiation
- 1º Visual Cortex
What is the Orientation that Visual fields are projected on the visual cortex?
In an inverted and reversed fashion
Which part of the Thalamus does does the Optic Tract travel through?
The Lateral Geniculate Nucleus of the Thalamus
What does a Damaged or Diseased optic nerve lead to?
Visual field defects
Where does the optic nerve synapse for the first time?
In the Thalamus
Where is the Primary Visual Cortex found?
In the occipital lobe
What divides the Primary Visual Cortex?
The Calcarine Sulcus
When does the Optic nerve become the Optic Tract?
When they pass the optic chiasm
What is Nerve II?
The optic nerve
What type of nerve is the Oculomotor Nerve (III)? (Sensory/Motor)
Mixed Sensory and Motor
Where does the Oculomotor Nerve arise from?
The midbrain
What is the Motor function of the Oculomotor nerve?
Move the eyeball in orbit
What is the Parasympathetic motor function of the Oculomotor nerve?
Pupillary constriction and accommodation (ciliary ganglia)
What extraocular muscles does the Motor Component of the Oculomotor Nerve innervate?
- Medial Rectus
- Superior rectus
- Inferior Rectus
- Inferior oblique
- Levator Palpebrae
What extraocular muscles does the Motor Component of the Oculomotor Nerve NOT innervate?
- Lateral Rectus
* Superior Oblique
What is the acronym for remembering which nerves innervate the muscles of the eye and explain it
LR6SO4
Lateral rectus is innervated by CN VI and Superior oblique is innervated by CN 4
What does Damage or Disease to the Oculomotor nerve result in?
- Pupillary dilation
* Ophthalmoplegia
What is Ophthalmaoplegia?
Eye movement weakened or paralysed
What are the 6 muscles of the eye?
- Medial rectus
- Superior rectus
- Inferior rectus
- Lateral Rectus
- Inferior oblique
- Superior oblique
- Levator palpebrae superioris
Explain the function of the Oculomotor nerve (Somatic/Autonomic and Sensory/Motor)
It has Somatic motor function and Parasympathetic functions
What are the Somatic Motor functions of the Oculomotor nerve?
Moving the eyeball
What are the Parasympathetic functions of the Oculomotor nerve?
Constriction of the iris and accomodation of the eye
What does the Superior Rectus muscle do?
Makes the eye look up
What does the Inferior rectus do?
Makes the eye look down
What does the Medial rectus do?
Makes the eye look medially
What does the Lateral rectus do?
Makes the eye look laterally
What does the Inferior Oblique do?
Elevates the anterior part of the eye
What does in Superior Oblique do?
Moves the eye down and out
What is the function of the Superior Levator Palpebrae muscle?
Lifts the eyelid
What is CN IV?
The Trochlear Nerve
What is the smallest Cranial Nerve?
CN IV the Trochlear nerve
What kind of nerve is the Trochlear Nerve? (Sensory/Motor)
Pure Motor
Which muscle does the Trochlear Nerve supply?
The Superior Oblique
Where does the Trochlear Nerve emerge?
The back of the brainstem
Why is damage to the Trochlear Nerve uncommon?
Because it’s really isolate
What is the Motor function of the Trochlear Nerve?
To move the Superior Oblique
What is the name of nerve VI?
The Abducens Nerve
What type of nerve is the Abducens Nerve? (Sensory/Motor)
It is pure motor
What is the motor function of the Abducens nerve?
Move the lateral rectus
What does the lateral rectus do?
Abducts the eye, hence the abducent nerve
Where is the Abducens nerve found?
At the Pontomedullary junction
Which nerve has the longest intracranial course of all nerves?
The Abducens nerve
What is the Abducens nerve vulnerable to?
Injury in head trauma or raised intracranial pressure
What does Damage to the Abducens do?
Paralysis of the lateral rectus causes nothing to oppose the medial rectus and the eye deviates medially causing double vision and squinting
Which nerve is sensitive to intracranial pressure and head trauma?
The abducens nerve
Which nerve can be responsible for Strabismus?
VI, the abducens nerve
What is nerve V called?
The Trigeminal Nerve
What nerves does the Trigeminal Nerve split into and what are their names?
- V1-Ophthalmic Nerve
- V2-Maxillary Nerve
- V3-Mandibular Nerve
What type of nerve is the Trigeminal Nerve? (Sensory/Motor)
Sensory and Motor
Where does the Trigeminal originate?
The pons
What type of nerve is V1? (Motor/Sensory)
Pure Sensory
What type of nerve is V2? (Motor/Sensory)
Pure Sensory
What type of nerve is V3? (Motor/Sensory)
Motor and Sensory
What does V1 innervate?
The eye
What does V2 innervate?
The cheek
What does V3 innervate?
The Mandible
What does CN V serve as a conduit for?
Parasympathetic functions of CN’s III, VII, IX
What disease is associated with the Trigeminal nerve?
Trigeminal Neuralgia (Tic Douloureux)
What is V2 responsible for?
All feeling around the cheek area
What is V1 responsible for?
Feeling in the eye
What is V3 responsible for?
Movement and sensation in the Mandible
What is found in the Trigeminal Ganglia?
The cell bodies for the sensory axons
What does V1 branch into?
The Supraorbital nerve
What is the function of V1 the Opthalmic nerve?
- Supplies sensation to the frontal and ethmoidal paranasal air sinuses
- Sensory innervation to nasal cavity
- Supplies sensation to upper eyelid, side of nose, forehead and scalp
Which nerve supplies sensation to frontal and ethmoid paranasal air sinuses?
V1 - Ophthalmic Nerve
Which nerve supplies sensory innervation to the nasal cavity?
V1 - The Ophthalmic nerve
Which nerve supplies sensation to the upper eyelid, side of nose, forehead and scalp?
V1 - Ophthalmic nerve
What is the Ciliary Ganglion?
Where cranial nerve III synapses onto V1 in order to constrict the pupil
What Ganglion is associated with V1?
Ciliary Ganglion
How does V2 enter the floor of the Orbit?
Through the inferior orbital fissure
What ganglion is associated with the Maxillary nerve?
Pterygopalatine ganglion
What does the Pterygopalatine ganglion do?
Serve as a synapse point for CN VII
What does the Maxillary nerve (V2) supply sensation to?
- Maxillary air sinus
- Nasal cavity
- lower eyelid, skin of cheek, upper lip
- Maxillary (upper) teeth and gums
Which nerve branches off V2?
The Infraorbital nerve
What does the Infraorbital nerve that branches off V2 do?
Supply sensation to:
•Lower eyelid, skin of cheek, upper lip
What kind of nerve is V3? (Sensory/Motor) + (Somatic/Autonomic)
It is a mixed nerve with somatic sensory and somatic motor function
What is the biggest nerve of the Trigeminal nerve?
Mandibular nerve V3
Which ganglion are associated with the Mandibular Nerve?
Submandibular (CN VII) and Otic (CN IX)
Where does V3 enter from?
The Infratemporal fossa
What is the motor function of V3?
Supplies the muscles of mastication
What are the Sensory functions of V3?
- Supplies lower lip and skin of mandible
- Mandibular teeth and gums
- sensation of anterior 2/3 of tongue
Which nerve supplies sensory information to the anterior 2/3 of tongue?
V3
Which nerve supplies the lower lip and skin of the mandible as well as mandibular teeth and gums?
V3
What does V3 end as?
The mental nerve of the chin
How does V3 help with proprioception of the jaw?
It carries information from muscles of mastication to the brainstem (force of bite)
Where does the Inferior Alveolar Nerve originate?
From V3
Which nerve does the Lingual nerve originate from?
From V3
What is the name of VII?
Facial nerve
What type of nerve is VII? (Motor/Sensory) (Autonomic?)
Somatic Motor
Somatic Sensory
Parasympathetic
What is the Facial Nerve attached to?
The pons
Where are the cell bodies of the sensory nerves of the Facial Nerve found?
In the geniculate ganglion
What does Damage or or Disease to the facial nerve cause?
- Inability to taste, inability to salivate and lacrimation in one eye
- Bell’s Palsy
What is the Motor function of the facial nerve?
Facial expression
What are the Sensory functions of the Facial nerve?
- Taste to the anterior 2/3 of tongue
* Some sensory skin around the ear
Which nerve supplies taste to the anterior 2/3 of the tongue?
The facial nerve via the chorda tympani
What are the Parasympathetic functions of the facial nerves?
Tearing and salivation
What does the lacrimal gland innervated by the facial nerve do parasympathetically?
Allow for tearing (lacrimation)
What do the Submandibular and Sublingual glands innervated by the facial nerves do?
Allow for salivation
What nerve does the lacrimal gland nerve join onto?
V2
What nerve does the submandibular and sublingual gland join onto?
V3
What are the main things that the facial nerve does?
Sensation of taste and movement of the facial muscle
Which branch of the facial nerve controls taste in the first 2/3rds of the the tongue?
The Chorda Tympani nerve
What are the Parasympathetic functions of the facial nerve?
Tearing and Salivation
What is the Somatic sensory function of the facial nerve?
Taste
What are the 4 main functions of the Facial nerve?
- Somatic Tasting
- Somatic Motor Facial expression
- Salivation
- Lacrimation
Which nerve does the Chorda Tympani of the facial nerve hitchhike on?
V3
What is the name of the branch of the Facial Nerve that is responsible for taste?
The Chorda Tympani
What is the name of Nerve VIII?
Vestibulocochlear Nerve
What type of nerve is the Vestibulocochlear nerve? (Autonomic/Sensory)
A Pure Sensory nerve
What are the two components of the Vestibulocochlear nerve?
The Vestibular and the Cochlear component
What does the Vestibular portion of the vestibulocochlear nerve supply?
Semicircular canals and vestibules for balance and equilibrium
What diseases arise as a result of issues with the Vestibular part of the vestibulocochlear nerves?
Meniere’s syndrome (vertigo, nausea, vomiting)
What does the Cochlear portion of the Vestibulocochlear nerve supply?
The organ of corti in cochlea for hearing
What is the pathway for the cochlear portion of the Vestibulocochlear Nerve?
Temporal lobe to Primary auditory cortex
What does damage or disease to the cochlear part of the vestibulocochlear nerve do?
Cause difficulty localizing sound and deafness
What is the name of nerve IX?
Glossopharyngeal nerve
What kind of nerve is the Glossopharyngeal nerve? (Motor/Sensory + Autonomic?)
Mixed Somatic Motor and Somatic Sensory and Parasympathetic
Which parts of the body does the Glossopharyngeal Nerve supply?
The Tongue and the Pharynx
What part of the brainstem is the glossopharyngeal nerve attached to?
The medulla
Which nerve regulates the gag reflex?
The glossopharyngeal nerve
What can damage to the Glossopharyngeal nerve cause?
Difficulty in swallowing, loss of gag reflex
What does the Motor portion of the glossopharyngeal nerve innervate?
The Stylopharyngeus which elevates the pharynx
What is the function of the Sensory portion of the Glossopharyngeal Nerve?
- Taste to posterior 1/3 of tongue
* Sensory to posterior 1/3 of tongue, pharynx, palatine tonsils, carotid sinus + body
What is the Parasympathetic function of the Glossopharyngeal Nerve?
The Parotid gland
What does the Parasympathetic portion of the glossopharyngeal (parotid gland) nerve hitchhike on?
V3 via the otic ganglion
Which nerve innervates Baroreceptors?
The glossopharyngeal nerve
What is the Parasympathetic function of the Glossopharyngeal nerve?
Salivary through the Parotid Gland
What is CN X known as?
The Vagus nerve
What kind of nerve is the Vagus Nerve? (Motor/Sensory + Autonomic?)
Mixed Motor, Sensory and Parasympathetic
Where does the Vagus nerve arise?
The medulla
What does damage to the vagus nerve cause?
Difficulty in speech and swallowing
What is the main motor function of the Vagus nerve?
Help with swallowing
What is the main parasympathetic function of the vagus nerve?
To ramp up digestion and slow down heart rate
What are the main Sensory functions of the Vagus nerve?
- Sensory receptors to eardrum
- Baroreceptors for hollow organs
- Carries visceral afferents
- Sensory to eardrum
- Sensory to muscles of the palate, pharynx and larynx
What is the name of nerve XI?
The Spinal Accessory nerve
What kind of nerve is the Spinal Accessory Nerve? (Sensory/Motor + Autonomic)
Pure Motor
Where does the Spinal Accessory nerve originate?
The medulla and upper spinal cord
What is the Cranial portion of the Spinal Accessory Nerve distributed to and by what?
Distributed by CN X to palate, pharynx and larynx
What is the Spinal portion of the Spinal Accessory Nerve distributed to and by what?
The spinal accessory nerve and supplies trapezius and sternocleidomastoid mastoid muscles in the neck
What does the Spinal portion of the Spinal Accessory Nerve innervate?
The trapezius and the Sternocleidomastoid muscles in the neck
What is the result of damage to the Spinal Accessory Nerve?
Weakness when shrugging shoulders and turning head to one side against resistance
What kind of Nerve is the Hypoglossal Nerve? (Sensory/Motor + Autonomic?)
Pure motor
Where does the Hypoglossal Nerve originate?
The medulla
What does the Hypoglossal Nerve innervate?
The muscles of the tongue
What does damage or disease to the Hypoglossal Nerve cause?
The inability to protrude tongue symmetrically