Question

Question 9 0.4 pts The descending pain control pathway involves inhibition of the activity in peptide by the opioid A-alpha axons ; dynorphin A-beta axons; endorphin C-fibers: enkephalin A-beta axons; endorphin

Answer 1

Question 9:

The descending pain control pathway involves the inhibition of activity in -- by the opioid --?

Answer: (C) C-fibers; enkephalin

1. Type Aα:- Proprioceptive function- has both Type Ia and Ib of the sensory fibers.

2. Type Aβ:- Type of mechanoreceptors- cutaneous receptors and is a Type II afferent fiber.

3. Group C:- Nociceptive in function; unmyelinated and relatively slow conduction velocity; nerve fibers at the dorsal roots and postganglionic fibers in the ANS

Enkephalins are small peptides that can serve as neurotransmitters in the brain. Enkephalins act to attenuate substance P release in the dorsal horn of the spinal cord and inhibit afferent pain fibers.

The descending pain control pathway triggers the release of serotonin and noradrenaline from their axons at the spinal level which further promotes the secretion of enkephalins from interneurons of the dorsal horn and spinal cord.