Neuroanatomy of toothache Flashcards
What are the 3 types of neurones
- Pseudo-unipolar neurones
- Bipolar neurones
- Multipolar neurons
Describe pseudo-unipolar neurons
- Sensory neurons that have no dendrites
- Branches axon serving both functions - one extends to organ like skin and the other to the spinal cord
Describe bipolar neurones
- Neurons that send signals and relieve information from the world (like ones in the eyes that receive light and transmit signals to the brain
Describe multipolar neurons
Neurones that receive impulses from multiple neurones, transmit signals down the axon by electrical impulse
What are the sensory pathways
- First order neurone
- From PNS to CNS
- Cell bodies in peripheral ganglia
- Pseudounipolar - Second order neurone
- Cell bodies in the CNS
- Axons cross midline
- Run to thalamus (part of diencephalon) - Third order neurone
- Run from thalamus to cerebral cortex - primary somatosensory area
What is a dermatome
- Specific region of the skin of the body innervated by the sensory fibres of a single segmental spinal nerve
- Areas of face are supplied by single cranial nerve, not a dermatome
Fill the gaps
What do sensory pathways do
General somatosensory pathways carry information of different modalities from skin, mucus membranes, joints and muscles to the brain
What are the modalities of sensory pathways
- Discriminative touch
- Pressure
- Vibration
- Proprioception
What are sensory pathways carried by
Carried via large diameter + heavy myelinated fibres
Do sensory pathways have a fast conduction?
Yes
What are the modalities of the spinothalamic pathway and trigeminothalamic pathway
- Pain
- Temperature
- Simple touch
- Some pressure
What are the spinothalamic pathways and trigeminothalamic pathways carried by
Thin, poorly myelinated and unmyelinated fibres
Do spinothalamic pathways and trigeminothalamic pathways have fast conduction?
No, it is relatively slow
What are the spinothalamic tracts responsible for
Sensory tract that carries neurones responsible for movement, pain, temp and crude touch
What neurones are the spinothalamic pathways made of
First, second and third order neurones
Fill the gaps
Describe the trigeminothalamic pathway
- Branches of the trigeminal nerve supply the innervation of the teeth
- Cranial nerves nuclei
Where are the trigeminothalamic pathways located
Within the brainstem
Describe the role of the motor and sensory fibres in the trigeminothalamic pathways
Motor - Give rise to motor fibres that leave the brainstem in cranial nerves
Sensory - Receive information form fibres entering brainstem in cranial nerves
What is the mesencephalic nuclei
Receives proprioceptive sensory information from the muscles of mastication
What is the role of the chief/principle nuclei
Responsible for 2 point discrimination, conscious proprioception, vibration and fine touch
What is the role of the spinal nucleus
- Caudal part - pain + temperature
- Rostral part - crude touch + pressure
