5 referred pain

Question 1

what is reffered pain?

Answer 1

¡Referred pain is the perception of visceral pain some way away from the organ involved

Does not accurately represent where the problem is

Signal from several areas of the body often travel through the same nerve pathways ->spinal cord -> brain

Question 2

where is visceral pain conducted along and why

Answer 2

visceral afferent fibres

General visceral afferent fibres (GVA) – conduct sensory impulses (usually pain/ reflex sensations) from viscera, glands, blood vessels to the CNS.

Considered to be part of the ANS, however the afferent fibers are not classified as either sympathetic or parasympathetic. (efferent has classification)

Cranial nerves that contain GVA include glossopharyngeal nn, vagus nn.

Question 3

Somatic vs visceral pain

Answer 3

somatic:

Epitomized by pain arising from the skin

Many modalities

Sensitive, well localised, often sharp

Many sensory receptors

visceral:

Fewer sensory endings in viscera

Often in smooth muscle

Poorly localised

Dull, heavy or gripping

May be referred

Question 4

anatomy of visceral afferent fibres

Answer 4

• Do not have a peripheral synapse (unlike visceral efferent (autonomic motor)
• Join a spinal (or cranial) nerve, enter the CNS along the dorsal nerve root (or CN equivalent)
• Cell body is found in the dorsal root ganglion
• enter spinal cord at: T1-L2 (sympathetics motor outflow), S2-4 (sacral parasympathetic outflow)

also applies to somatic body wall afferents

Question 5

mechanism of referred pain

Answer 5

The explanation for referred pain is not known

Nociceptors from several locations converge on a single ascending tract in the spinal cord

Pain signal from the skin are more common

Brain associates activation of the pathway with pain in the skin

Question 6

Answer 6

Question 7

Answer 7