General Receptors - Nociceptors

Pain Receptors - Nonciceptors

found in skin and internal organs

Types of pain receptors

1. Somatic

2. Visceral

Somatic nociceptors

• skin and skeletal muscles

• Respond to mechanical, thermal, electrical, or chemical damage in these tissues

• Examples: skinning a knee, straining a muscle, burning a finger

Visceral nociceptors

• internal organs

• responds to excessive stretching of the internal organs, oxygen deprivation when blood supply is reduced, or chemicals released by damaged tissue

• Examples: pain when the stomach is too full, pain from a heart attack

Referred pain

• stimulation of internal pain receptors is sometimes felt as pain from the skin as well as the internal organs

  • somatic pain nociceptors travel in the same pathway as the internal visceral nociceptors

  • brain cannot distinguish between the two

Examples of referred pain

• pain from a heart attack is often accompanied by pain in the left shoulder and arm

• brain freeze gain is in mouth and throat but vagus nerve is stimulated and pain is felt in brain and back of head

• intestinal pain felt in upper back between shoulder blades