Somatosensory 3

Question 1

Trigeminal nerve innervation

Answer 1

CN V most of the head

Question 2

Facial nerve innervation

Answer 2

Facial nerve Cn VII : part of the ear

Question 3

Glossopharyngeal nerve innervation

Answer 3

CN IX: throat

Question 4

Spinal nerve C2

Answer 4

Part of pinna, cranial neck

Question 5

Spinal nerve C3 innervation

Answer 5

Caudal neck

Question 6

Branches of the trigeminal nerve

Answer 6

Ophthalmic
Maxillary
Mandibular

Question 7

Sensory modalities of the trigeminal nerve

Answer 7

Touch, pain, temp, jaw position, muscle stretch

Question 8

Trigeminal ganglion

Answer 8

In trigeminal canal of temporal bone
Contain neuron cell bodies from first order sensory neurons

Question 9

Trigeminal sensory nuclei

Answer 9

3 sensory nuclei in the brainstem
Spinal - pain & temp
Pontine - light touch & proprioception
Mesencephalic - input from muscle spindles

Question 10

First order neuron for trigeminal pathways

Answer 10

Processes in branches of CN V
Cell bodies in trigeminal ganglion
Synapse in trigeminal sensory nuclei in brainstem

Question 11

Second order neurons in trigeminal pathways

Answer 11

Crosses midline
Ascends in the trigeminothalmic tract
Synapses in thalamus

Question 12

Third Order neuron trigeminal pathways

Answer 12

Cell bodies in thalamus
Projects to primary sensory cortex

Question 13

Somatosensory parts of VII and IX
First order neurons

Answer 13

cell bodies in separate ganglia associate w the cranial nerves

Question 14

Second and third order neurons of VII and IX

Answer 14

Same as trigeminal

Question 15

Visceral sensation

Answer 15

Sensory information from viscera (internal organs, heart, lungs stomach)
- can’t sense itch or temperature
Can sense stretch

Question 16

Receptors of visceral sensation

Answer 16

Mechanoreceptors - stretch & distention
Chemoreceptors- pH, oxygen levels, CO2
Nociception - tissue damage, inflammation, ischemia

Question 17

Visceral pain

Answer 17

Dull, aching pain
Poorly localized
- colic, pancreatitis, urinary obstruction, bowel obstruction

Question 18

Visceral pain receptors

Answer 18

Free nerve endings w specialized ion channels
Opening channels cause depolarization (transient receptor potential)
If depolarization reaches threshold, action potential fires

Question 19

Visceral pain pathways

Answer 19

Dual innervation of viscera
Somatic - spinal nerves
Autonomic - sympathetic: splenic nerves
Parasympathetic: vagus & sacral nerves

Question 20

How signal is transmitted in visceral pain pathways

Answer 20

Signal ascends to the brain via the Spinothalamic and dorsal somatosensory pathways

Question 21

Nociceptive or physiologic pain

Answer 21

Visceral or somatic pain
Caused by damage or potential damage to tissue

Question 22

Neuropathic pain

Answer 22

Pain due to disease of nervous system
Burning, prickling, tingling
Can be central or peripheral

Question 23

Causes of neuropathic pain

Answer 23

Trauma
Metabolic disease
Neurotoxic chemical
Infection
Tumor invasion

Question 24

Mechanisms of neuropathic pain

Answer 24

Abnormal generation of action potentials by nociceptors
Decreased threshold for action potentials in first order neurons

Question 25

Recognizing neuropathic pain

Answer 25

Constant chewing, biting, scratching at same spot Spontaneous vocalization Defensive to touch Hypersensitivity - hyperalgesia, allodynia

Question 26

Sensitivities for neuropathic pain

Answer 26

Loss of inhibitory interconnections in the spinal cord or brain Activation or attack of the nervous system by immune cells CNS sensitization to pain signals Abnormal neural pathways