Cranial Nerves (Lecture) Flashcards
T or F: cranial nerves and their ganglia are part of the peripheral nervous system
True
Which cranial n. does not originate from the cranial cavity?
XI
Where do cranial nerves travel before exiting the named foramina and fissures?
On the Cranial Floor
What gives rise to the origin or a spinal nerve?
Fusion of dorsal (sensory) and Ventral (motor) rootlets
T or F: like spinal nerves cranial nerves also participate in forming similar nerve plexuses
False
T or F: crainial motor and sensory fibers of the cranial nerves are combined and attached at approximately the same point on the brain
True
What cranial nerves direct their fibers into sensory ganglia?
Most of the CNs that contain a sensory component:
- V, VII, VIII, IX, and X
e.g. Trigeminal Ganglion
T or F: the sensory ganglia of cranial nn. are often further removed from the origin of the nerve in the CNS than the sensory ganglia of spinal cords
True
What two cranial nerves are sensory yet do not associate with an organized sensory ganglia?
I and II
*Note: these nerves are purely sensory
What do GSA cranial nerves do?
Sensation from:
- Somatic Structures (skin, msucle, fascia, joints, tendons, peristeom etc.)
Sensation of Mucosal Lining:
- Oral Cavity
- Nasal Cavity
- Nasal Sinuses
- Pharynx
- Esophagus
- Larynx
- Trachea
- Middle Ear
What does the GVA component of cranial nerves do?
- Sensation from visceral structures of the head (carotid body and carotid sinus)
- Thoracic and Abdominal Viscera (Foregut and Midgut)
What does the SA component that’s unique to cranial nerves do?
- Sensation from specialized receptors in the head which are related to (Vision, Hearing, Equilibrium, Taste and Smell)
What cranial nerves contain a special sensory component?
- I, II, VII, VIII, IX, X
What does the GSE component of Cranial Nerves do?
- Motor innervation to skeletal muscle in the head derived from SOMITE MESODERM
What does the GVE component of Cranial nerves do?
- CNs involved
- Parasympathetic Motor Innervation to smooth muscle and glands of the head
- Only in CNs III, VII, IX, X
What does the BE (Branchiomeric Motor, SVE) component of Cranial Nerves do?
- Motor to Skeletal Muscle in head derived from branchial (pharygeal arch) mesoderm
Which skeletal muscles of the head:
- Paraxial vs. Pharyngeal Arch mesoderm
- Location
- Innervation
Paraxial Mesoder:
- More Posterior
- Orbit and Tongue (and a couple other structures)
- Traditional GSE innervation
Pharyngeal Arch Mesoderm:
- More Anterior
- Everything else
- Branchiomeric Motor Innervation (BE)
What arises from the 5th pharyngeal arch?
Nothing, it rudimentary
What is the innervation of each of the Pharyngeal Arches?
Arch 1 (mandibular arch): V3 Mandibular of Trigeminal (V)
Arch 2 (Hyoid arch): VII Facial
Arch 3: IX Gloassopharyngeal
Arch 4-6: X Vagus
Which Muscles innervated by cranial nerves develop from Somite mesoderm?
- All muscle of the tongue (CN XII), EXCEPT palatoglossus
- Skeletal muscles of Orbit (III, IV and VI)
- Sternocleidomastoid (XI)
- Trapezius (XI)
**THESE ARE NOT branchiomeric muscles
What muscles are derived from the first pharyngeal arch?
- Innervation
MAST-MATT
Muscles of MASTication:
- Medial pterygoid
- Lateral Pterygoid
- Temporalis
- Masseter
Mylohyoid muscle
Anterior belly of digastric muscle
Tensor Veli Palatini Muscle
Tensor Tympani Muscle
**Innervation = CN V3 mandibular
What muscles are derived from the second pharyngeal arch?
- Innervation
Muscles of Fascial Expression
Posterior Belly of Digastric Muscle
Stylohyoid muscle
Stapedius Muscle
**Innervation = CN VII facial
What muscle are derived from the third pharyngeal arch?
- Innervation
Stylopharyngeus Muscle
**CN IX; glossopharyngeal
What muscles are derived from the 4th and 6th pharyngeal arches?
- Innervation
- All Muscles of larynx
- All muscles of palate, EXCEPT tensor veli palatini (V3)
- All muscles of pharynx, EXCEPT stylopharyngeus (IX)
