The Trigeminal System Flashcards

1
Q

What is the nervous system made up of?

A

CNS: - brain and spinal cord

Peripheral NS: - spinal nerves and cranial nerves

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2
Q

What does the primary afferent nerve do?

What is trigeminal sensory nuclei?

Name the pathway of nerves:

Where does it synapse?

A

Primary afferent: takes info from periphery into CNS at first synapse

Trigeminal sensory nuclei: synapse with second order neurone - crosses midline and synapses in thalamus

This pathway of nerves is called the trigemino-thalmic tract

In thalamus on contralateral side, it synapses with a nerve at the somatosensory cortex

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3
Q
A
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4
Q

What is the peripheral trigeminal nerve made up from:

A
  • 3 divisions: opthalmic, maxillary, mandibular
  • 1 ganglion: trigeminal (or semilunar/gasserian)
  • also trigeminal mesencephalic nucleus
  • 2 roots: sensory, motor, both enter at pons
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5
Q

What are the 4 structures in the trigeminal sensory nuclear complex?

A
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6
Q

What is the main function processed at nucleus caudalis?

A

Damage to nucleus caudalis or trigeminal tractotomy:

  • loss of ipsilateral facial pain, hot/cold
  • still feel touch

Therefore, nucleus caudalis is the site for suynapses for pain, hot and cold

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7
Q

Function of nucleus oralis?

A

Nociceptive inputs to nucleus oralis especially for teeth

  • ? necessary for oral and dental pain
  • ? nociceptive neurones in nucleus oralis for reflexes rather than sensation
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8
Q

Function of main sensory nucleus?

A

Damage to MSN

  • ipsilateral loss of funtion to face
  • still feel pain, hot and cold

Experiment was carried out by small no. of pts with other CNS lesions aswell

Conclusion: MSN is probably the site for synapses for touch

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9
Q

What are the likely function of trigeminal sensory nuclei?

  • main sensory nucleus
  • nucleus caudalis
  • nucleus oralis
  • nucleus interpolaris
A
  • main sensory nucleus: probable synapses for touch
  • nucleus caudalis: synapses for facial pain and hot/cold, possible site for oral/dental pain
  • nucleus oralis: possible site for oral/dental pain, reflexes
  • nucleus interpolaris: reflexes
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10
Q

Functions of motor root of peripheral trigeminal nerve?

Where are the cell bodies for these functions?

Where do they synapse?

A
  • sends signals to muscles of mastication
  • efferent: takes signals from CNS to PNS
  • also contains some afferents: muscle spindles and PDL mechanoreceptors

Trigeminal mesencephalic nucleus contains cell bodies for:

  • jaw muscle spindle afferents
  • some mechanoreceptive afferents from the PDL

Synapse in trigeminal motor nucleus

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