Trigeminal System Flashcards
3 nucleus’s the the trigeminal system?
- chief sensory nucleus
- trigeminal spinal nucleus
- mesencephalic nucleus
where is the chief sensory nucleus located?
pons
where is the trigeminal spinal nucleus located?
medulla and spinal cord
How does the chief sensory nucleus send off its branches?
from each nucleus it sends off an ipsilateral and contralateral branch to the VPM nucleus of the thalamus.
how does the chief nucleus nucleus ascend and where does it do to?
ascends via the trigeminothalamic tract to the VPM of thalamus
does the trigeminal spinal nucleus decussate?
yes it does completely
the spinal trigeminal nucleus ascends via the ____ to the ____
ascends via the trigeminothalamic tract to the VPM of thalamus
the principal/ chief nucleus is similar to the _____ pathway?
DCML (ascends close to medial lemniscus)
the spinal trigeminal nucleus is similar to the _____ pathway?
ALS
describe the reflex arc of the trigeminal system?
sensory info comes from V3 and goes to the mesencephaic nucleus (located in the upper trigeminal spinal nucleus) it the synapses outside the nucleus on a motor branch of V3.
how does sensory info make it from the trigeminal ganglion to the spinal trigeminal nucleus?
it descends via the spinal trigeminal tract.
what does the chief/ principal nucleus mediate?
fine touch, joint position and vibration
what does the spinal trigeminal nucleus mediate?
pain and temperature - associated with ALS
where is the spinal trigeminal nucleus located?
medulla to c2-c3 - continuous with the dorsal horn
what is the trigeminal motor nucleus similar to?
homologous to the ventral horn in the spinal cord
where is the trigeminal motor nucleus located?
medial to the prinicpal/ chief nucleus
what is a consensual reflex?
it occurs in both sides. the ipsilateral reflex occurs faster than contralateral
eye blink response ( touch cornea)
input
output
input - trigeminal nerve to chief nucleus (touch cornea)
output - facial nucleus to facial nerve - contract orbicularis oris of both eyes = consensual
why is the eyeblink response consensual?
b/c the facial nerve splits bilaterally to innervate both sides
what is the most common error in dentistry in regards to the inferior alveolar nerve?
neglegent implant placement
what are you more likely to have complication in extracting, a maxillary 3rd molar or a mandibular 3rd molar?
- mandibular teeth are harder and more dangerous b/c only one nerve (inferior alveolar nerve)
what are the 3 types of nerves in the pulp?
proprioceptive
nociceptive
sympathetic
What type of nerve develops 1st in the pulp?
nociceptive nerves for 1st in development- this is why in dentinal tubules
what is the second nerve to develop in the pulp?
proprioceptive nerves
what is the last nerve to develop in the pulp and why?
sympathetic nerves are the last to develop. The tooth errups as soo as sympathetics enter. If distorted you will loose the tooth b/c it suppresses inflammation
are there parasympathetics in the tooth?
no just like skin
what does an inferior alveolar nerve block do?
anesthetizes the mental , incisive, lingual and long buccal nerve.
what happens if a needle enters the inferior alveolar nerve?
partial injury with paresthesia - resolves
why do you shake someones cheek when giving an injection?
b/c tactile sensation is fast and it will block/ overwhelm the nociceptive signaling pathway.
the ipsilateral fibers of the chief nucleus travel in the
dorsal trigeminothalamic tract
the contralateral fivers of the chief nucleus travel in the
ventral trigeminothalamic tract
what is continuous with the dorsal horn?
the spinal trigeminal nucleus
what is continuous with the ventral horn?
the trigeminal motor nucleus
