Cranial Nerves- Anatomy/Function Flashcards
What is visceral?
Internal organs Respiratory apparatus (speech muscles, branchial arches)
What is somatic?
Skeletal
Skin
Ligaments
Joints
What are general sensory modalities?
Fine touch Crude (light) touch Pain Temperature Vibration
What are special sensory modalities?
Taste Smell Vision Hearing Balance
What helps to organize the way BOTH spinal and cranial nerves transmit information to the nervous system?
Sensory modalities
Functional components
What is a sensory modality?
Conscious perceived sensation from the skin
How is general sensory AFFERENT information conveyed?
Fibers distributed throughout head and body
-originates from body
How is special sensory AFFERENT information conveyed?
Via CN ONLY
-concentrated in small localized zones
How is general motor SOMATIC EFFERENT information conveyed?
spinal AND motor nerves innervated voluntary muscles (CN III, IV, VI, XII)
How is special motor VISCERAL EFFERENT information conveyed?
cranial motor nerves ONLY innervate skeletal muscles (CN V, VII, IX, X, XII)
What are the motor components of the CN that serve speech muscles?
SVE (special/visceral/efferents)
GVE (general/visceral/efferents)
OR BOTH
What are the motor components of the CN that serve speech muscles?
WHICH CN IS THE EXCEPTION TO THIS?? hint: it’s GSE
Hypoglossal
GSE (general/somatic/efferent)
Derived from similes
Which 6 cranial nerves are important to speech?
Trigeminal (CN V) Facial (CN VII) Glossopharyngeal (CN IX) VAGUS (CN X) Accessory (CN XI) Hypoglossal (CN XII)
Name the 12 cranial nerves
I OLFACTORY II OPTIC III OCCULOMOTOR IV TROCHLEAR V TRIGEMINAL VI ABDUCENS VII FACIAL VIII ACOUSTIC-VESTIBULAR IX GLOSSOPHARYNGEAL X VAGUS XI ACCESSORY XII HYPOGLOSSAL
what are the CN associated with hearing and balance
Acoustic-vestibular (CN VIII)
Which cranial nerves are purely sensory?
Olfactory (I)
Optic (II)
Acoustic-vestibular (VIII)
Which cranial nerves are PURELY motor?
Oculomotor (III) Trochlear (IV) Abducens (VI) Spinal accessory (XI) Hypoglossal (XII)
Which cranial nerves are mixed with motor and sensory?
Trigeminal (V)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
Where is the olfactory nerves located?
Telencephalon
Where is the optic nerve located?
Diencephalon
Where are cranial nerves III-XII located?
On the brainstem
Which 3 cranial nerves are involved in the movement of the eyeballs?
Occulomotor
Abducens
Trochlear
What is the difference between the sensory and motor cranial nuclei?
Sensory: nuclei of termination of afferent fibers (first order neurons)
Motor: nuclei of origin of LMN (final common pathway)
What are the 2 processes of the somatic unipolar neurons?
Peripheral process: to receptor
Central process: to CN nucleus
Where are the cell bodies of the sensory neurons?
In ganglia (outside of CNS)
What are the lower motor neurons innervated by?
Which pathways is used?
LMN innervated BG UMN
USES: Corticobulbar pathway
How do the UMN innervated with the motor cranial nerves?
Bilaterally /both hemispheres
LOWER FACE & TONGUE: contra lateral ONLY
Where is the trigeminal nerve located?
Pons
Name the 3 branches of the trigeminal nerve & what type of nerves they are
Ophthalmic (sensory)
Maxillary (sensory)
Mandibular (mixed)
The trigeminal ganglion is also called…
Semilunar
Gasserian
What are the 3 sensory nuclei of termination of the trigeminal cranial nerve (V)?
Main sensory nucleus
Spinal nucleus of V
Mesencephalic nucleus
The main nucleus of the Trigeminal nerve can also be called?
Chief sensory nucleus
Principal sensory nucleus
The main nucleus receives input from where?
About what type of General sensory information?
Light touch
Fine discriminative sensation
Input: face, mouth, anterior scalp (FROM ALL THREE BRANCHES)
What is the function of the spinal sensory nucleus of the trigeminal nerve?
Where does it get its input?
Mediates sensory portion of facial reflexes
Gets general sensory from tongue (mandibular nerve)
Input: pain and temperature (FROM ALL 3 BRANCHES)
What is the function of the Mesencephalic sensory nucleus of the trigeminal nerve?
Where does it get its input?
Conscious and unconscious proprioception
Innervates: Muscles of mastication Mylohyoid & digastric Tensor veil palatini Tensor tympani Mentalis
The first branch of the trigeminal nerve serves what type of input to what location?
The ophthalmic branch inputs SENSORY input to:
Upper face (eyeballs, eyelids, cornea)
Upper/ outer nose
Anterior scalp & forehead
The second branch of the trigeminal nerve serves what type of input to what location?
The maxillary branch of the trigeminal nerves sends SENSORY input to:
Midface Cheeks Lower nose/ nostrils Upper lip, teeth & alveolus Hard and soft palate
The third branch of the trigeminal nerve serves what type of input to what location?
The mandibular branch of the trigeminal nerves send MIXED input.
The sensory input is to:
Lower face Lower lip, lower teeth & alveolus Skin of mandible TMJ (temporomandibular joint) General sensory to anterior 2/3 tongue
The third branch of the trigeminal nerve serves what type of input to what location?
The mandibular branch of the trigeminal nerve gives MIXED input.
The motor input goes to:
Innervates: (same as MESENCEPHALIC) Muscles of mastication Mylohyoid & anterior belly of digastric Tensor veil palatini Tensor tympani Mentalis
What are major functions of CN V?
Mediates input of facial reflexes
Mediates input AND output of jaw jerk reflex
What type of nerve is the facial nerve (VII)?
What is it’s location
It’s a mixed nerve
It’s on the lower pons
What are the three functions of the facial (VII) cranial nerve?
Taste (SVA)
Motor to ALL facial muscles & 2 suprahyoids (posterior digastric and stylohyoid) & stapedius muscle (SVE)
Motor salivation & tears (GVE)
What is the name of the facial nerve ganglion?
Geniculate ganglion
How many nuclei does CN VII have? Name them and their function
Solitary nucleus: taste
Spinal nucleus of V: General sensory
How is taste interpreted from the facial nerve?
To solitary nucleus
Via chorda tympani branch
How are the general sensory modalities interpreted from CN VII?
From ear canal and skin behind the ear
To spinal nucleus of V
How is motor innervation supplied from CN VII motor nucleus?
Lower half: contra lateral cortical UMN supply
Upper half: bilateral cortical UMN supply
What are the 5 facial motor branches?
Temporal Zygomatic Buccal Mandibular Cervical
What areas do the CN VII branches supply?
ALL facial muscles
Posterior digastric & stylohyoid
Stapedius of the middle ear
What is the main function of CNVII?
Mediates MOTOR components of facial reflexes
CN V mediates SENSORY component
How do facial reflexes travel?
In through CN V
OUT through CN VII
What does the jaw jerk travel?
IN & OUT through CN V
What are the signs of a facial nerve pathology involving UMN?
Closing eyes wrinkles forehead
Lower facial quadrant paresis (facial asymmetry/ impaired labial retraction)
common in stroke victims
What are the signs of a facial nerve pathology involving UMN?
Signs are unilateral
Little or NO mobility
Facial lines disappear
Entire half face involved
What is Bell’s palsy?
Can people recover?
Acquired LMN disorder
Labial corner droops
No known etiology
Most cases recover
