5.3 Trigeminal Neuroanatomy Flashcards
Where in the CNS is the mesencephalic nucleus?
midbrain
Where in the CNS is the chief sensory nucleus?
pons
Where in the CNS is the spinal trigeminal nucleus?
medulla
What type of sensory modality does the chief sensory nucleus receive?
discriminative tactile and pressure input from the face and oral cavity
What type of sensory modality does the spinal trigeminal nucleus receive?
Pain and temperature inputs from the face and oral cavity
What type of sensory modality does the mesencephalic nucleus receive?
proprioceptive input from the head (muscles of mastication, teeth and hard palate, TMJ)
What cranial nerves have 1st order sensory neurons that synapse in the spinal trigeminal nucleus?
CN V, VII, IX, X
Which thalamic nucleus receives sensory info from the sensory trigeminal nuclei?
VPM nucleus of thalamus
Axons from the Chief sensory nucleus ascend ipsilaterally as what tract?
dorsal trigeminothalamic tract
Axons from the Spinal trigeminal nucleus cross and ascend as what tract?
ventral trigeminothalamic tract
Where do the dorsal and ventral trigeminothalamic tracts project to/terminate?
3rd order VPM –> project to face area of post central gyrus
Where is the trigeminal motor nucleus?
pons
Are the cell bodies in the trigeminal motor nucleus upper or lower neurons?
lower neurons that innervate muscles of mastication
What are the 2 sources of input that the trigeminal motor nucleus receives?
bilateral corticobulbar (upper motor neurons) and mesencephalic nucleus
What is the afferent limb of the jaw jerk reflex?
sensory portion of V3
What is the efferent limb of the jaw jerk reflex?
motor branch of V3
If the jaw jerk reflex is present, what motor neurons were damaged in the trigeminal motor system?
corticobulbar pathways (upper motor neurons) –> trigeminal motor nucleus
What is the efferent limb of the corneal reflex and where are its cell bodies?
CN VII cell bodies in facial motor nucleus
What happens with the corneal reflex if there is a CN V1 lesion?
no direct or consensual reflex = can’t blink on either side
What happens with the corneal reflex if there is a left CN VII lesion?
No direct = can’t blink left eye
intact consensual = right eye will blink
What is the efferent limb of the lacrimal reflex and where are its cell bodies?
CN VII transmits impulses via superior salivatory nucleus
What is the oculocardiac reflex?
bradycardia induced by compression of the eye ball
What is the afferent pathway of the oculocardiac reflex?
CN V1
What is the efferent pathway of the oculocardiac reflex?
dorsal motor nucleus of CN X (preganglionic parasympathetic fibers to cardiopulmonary plexus)
