Cranial nerves Flashcards
(94 cards)
Where are the GSE cell bodies of CN III located?
Oculomotor nucleus in the rostral mesencephalon at the level of the rostral colliculi
The oculomotor nucleus is responsible for innervating several extraocular muscles.
What muscles does CN III innervate?
- Medial rectus
- Dorsal rectus
- Ventral rectus
- Ventral oblique
- Levator palpebrae superioris
These muscles control eye movement and eyelid elevation.
How does CN IV exit the cranial cavity?
Through the orbital fissure
In some horses, it may exit through the trochlear foramen.
What is unique about CN IV regarding muscle innervation?
It is the only cranial nerve with GSE neurons that innervate a muscle solely on the side opposite its nucleus
This means that the dorsal oblique muscle is innervated from the opposite side of the brain.
What muscles does CN VI innervate?
- Lateral rectus
- Retractor bulbi
These muscles are involved in eye movement.
What is the physiological response of nystagmus?
A move to the right results in fast phase jerk to the right
This involves coordinated movement of the eyes in response to head movement.
What results from lesions of CN VI?
Paralysis of lateral rectus leading to medial strabismus
Medial strabismus is characterized by the eye deviating medially.
What are the GSE cell bodies of CN V located?
In the motor nucleus in the pons
The trigeminal nerve is responsible for sensations in the face and motor functions such as biting and chewing.
What muscles does CN VII innervate?
- Muscles of facial expression
- Caudal digastricus
These muscles are responsible for movements such as smiling and frowning.
What is the function of the nucleus ambiguous?
Contains GSE neuronal cell bodies for CN IX, X, and XI
This nucleus plays a crucial role in regulating muscles involved in swallowing and speech.
What branches does CN IX provide?
Pharyngeal branches to pharyngeal muscles
These branches form part of the pharyngoesophageal plexus with CN X.
How does CN X exit the cranial cavity?
Through the jugular foramen
It is involved in various autonomic functions.
What does the internal branch of CN XI join?
Joins the vagus nerve
The accessory nerve has both cranial and spinal roots.
What does the external branch of CN XI innervate?
- Intrinsic muscles of the larynx
- Cervical and cranial thoracic esophagus
- Trapezius
- Sternocephalicus
- Cleidocephalicus
These muscles are involved in neck movement and swallowing.
Where are the GSE cell bodies of CN XII located?
In the motor nucleus in the medulla
This nerve is primarily responsible for tongue movement.
What muscles does CN XII innervate?
- Styloglossus
- Hyoglossus
- Genioglossus
- Intrinsic tongue muscles
- Geniohyoideus
These muscles are essential for movements such as speaking and swallowing.
What cranial nerves are involved in the parasympathetic GVE LMN of the Medulla?
CN VII, IX, X, XI
Where are the preganglionic GVE LMN nuclei located in relation to the hypoglossal nucleus?
Dorsal, adjacent to the floor of the fourth ventricle, and lateral to the hypoglossal nucleus
What is the location of the parasympathetic nucleus for CN VII?
Rostral in the medullary column
What do the preganglionic axons of CN VII join to enter the internal acoustic meatus?
CN VII GSE motor neurons
What structure do the preganglionic axons of CN VII join with to form the nerve of the pterygoid canal?
Major petrosal nerve and deep petrosal nerve
Where do the preganglionic parasympathetic axons of CN VII synapse?
Pterygopalatine ganglion
What glands are innervated by the ganglionic axons from CN VII?
- Lacrimal gland
- Gland of the 3rd eyelid
- Palatine glands
- Lateral and mucosal nasal glands
What does the chorda tympani branch off from in CN VII?
Other preganglionic axons within the facial canal