The trigeminal nerve and galgnion are to the head what the spinal nerves and ___ are to the body as far as transmission of sensory informaiton is concerned.
Where are the cell bodies of the primary afferent fibers for the trigeminal pathway?
in the trigeminal ganglion
How many nuclei does the trigeminal pathway have and what info do they hold?
three are sensory and 1 is motor
What are some common pain syndromes involving trigeminal dermatomes?
TMJ, earaches, headaches, toothaches, sinus pain, trigeminal neuralgia
What areas of the body receive afferent supply from the trigeminal pathway?
top of head
anterior 2/3 of tongue = touch NOT taste
proprioceptors for the jaw
Three areas that are innervated only receive pain sensation regardless of the stimulus. What are they?
teeth, cornea, and eardrum
Where does efferent motor output go in the trigeminal pathway?
muscles of mastication and the tensor tympani
What are the three trigeminal sensory nuclei called?
What would be the impact of damage to the motor nucleus of the trigeminal nerve and its efferent fibers on muscles of mastication?
- paralysis of the contralateral mastication muscles
sensitivity to noise
mouth muscles would atrophy, so mouth would devidate to the affected side.
What type of information do the second order neurons int he SPINAL TRIGEMINAL NUCLEUS carry? THrough what tract?
mostly nociceptive (but some tactile) through the ventral trigeminothalamic tract
What type of receptors giev the major amount of input to the main sensory nucleus of the trigmeinal pathway?
What tract do the main sensory nucleus second order axons join to reach the VPM?
the ventral trigeminothalamic tract
What is the special situation for information related to intraoral mechanoreception?
A small component of the secondary axons from the main sensory nucleus project ot the IPSILATERAL VPM via the corsal trigeminothalamic tract instead of going contralateral with the ventral trigeminothalamic tract
How is the somatotopic organization of the VPM?
the face projections are positioned laterally in the nucleus, taste is medial and intraoral is betwen them
Here's an important exception!!
Where are the cell bodies (pseudounipolar neurons) of the neurons that synapse on the mesencephalic trigeminal nuclei?
They're located in the pons and midbrain! Not the trigeminal gnalgion!
it's a developmental quirk
Describe the jaw jerk reflex....
the pseudounipolar neurons with cell bodies in the mesencephalic trigeminal nucleus receive stretch input from the peridontium and muscles of mastication
axons project to the motor nucleus of the trigeminal pathway
motor fibers running back down to the muscles of mastication are activated in the jaw jerk reflex