Neurologic Exam Week 9

What fibers carry fast pain?

Ad fibers (type III)

What fibers carry chronic pain?

C fibers (Type IV)

Which tract carries pain?

Lateral spinothamaic tract

Which reed lamina carries pain in the spinal cord?

2 (substantia gelatinosa)

How is pain modulated in the ascending pathway?

mechanoreceptors/large diameter fibers inhibiting nociceptors

What centres of the brain modulate pain?

Somatosensory cortex

Thalamus

Periaqueductl gray

Ventral tegmental area

Rostal ventromedial medulla

Raphe nuclei

What is stimulated by the periaqueductal ray?

Rostral ventromedial medulla (RVM)

Nucleus raphe magnus

Reticular formation ventral

Where is the periaqueductal gray?

Midbrain

Where do the transmissions from the periaqueductal ray eventually transmit to?

Lamina I, II, and V

What is released by the RVM, raphe nucleus, and reticular formation to lower pain transmission?

Glycine

What opioids are used to suppress pain in the spinal cord?

Enkephalin

Dynorphin

What is the key descending tract for modulating and lowering nociception?

Raphespinal tract

Which psychological factors affect perception of pain?

Arousal

Attention

Expectation

What is the term for the idea that pain results from balance of nociceptive and nonnociceptive afferent activity?

Pain gate theory

What type of neuron do nociceptors stimulate?

Interneuron

What is released by nociceptive interneurons?

Substance P

What does substance P do?

Increases pain

What do mechanoreceptors release to lower pain perception?

Enkephalin

What is the main inhibitory compound din the natural pain gate theory?

Glycine

What part of the body is glycine used in?

PNS

What part of the body is GABA used in?

CNS

What are other inhibitory compounds used in pain modulation?

Glycine (PNS)

GABA (CNS)

Noradrenaline

Opioids

5-HT (serotonin)

Cannabinoids

Adenosine

What is the AKA of 5-HT?

Serotonin

What type of fibers close the pain gate?

Type II afferents

How does a chiropractic adjustment reduce pain?

Increases mechanoreceptor firing, closing the pain gate