Cutaneous pain

Cutaneous pain is felt in superficial structures such as the skin and subcutaneous tissues. A pin prick and a paper cut are examples of cutaneous pain.

Periaqueductal Gray Matter in Midbrain

Enkephalin

Nucleus Raphe Magnus in Medulla

Nociceptive stimulus

Substance P

Spinal cord (Dorsal horn)

Substance P

Spinal cord (Dorsal horn)

Figure 8.2 The endogenous analgesic system. The three major components of the endogenous analgesic system include the periaqueductal gray matter in the mid-brain; nucleus raphe magnus in the medulla; and pain inhibitory complex in the dorsal horns of the spinal cord. This system causes presynaptic inhibition of pain fibers entering the spinal cord. The binding of enkephalin to opioid receptors on the pain fibers prevents release of the neurotransmitter, substance P. As a result, the pain signal is terminated in the spinal cord and does not ascend to higher centers in the CNS.

It is a sharp pain with a burning quality that may be easily localized. This pain may be abrupt or slow in onset.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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