Physiology VIII: Pain and Thermosensation

There are 3 types of pain: [blank_start]Nociceptive pain[blank_end]: The normal response to noxious insult or injury of tissues such as skin, muscles, visceral organs, joints, tendons, or bones. [blank_start]Inflammatory pain[blank_end]: The result of activation of the pain pathway by the release of a variety of mediators such as IL-1-alpha, IL-1-beta, IL-6 and TNF-alpha. [blank_start]Pathological pain[blank_end]: A disease state caused by damage to the nervous system or by its abnormal function

The peripheral primary sensory afferent neurons activated by noxious stimuli are called [blank_start]nociceptors[blank_end]

Types of Nociceptor: [blank_start]A-delta-fibres[blank_end] respond to 'fast pain' such as stabbing, pricking, etc [blank_start]C-fibres[blank_end] respond to 'slow pain' such as burning, throbbing, cramping.

An increased sensitivity to pain is called [blank_start]Hyperalgesia[blank_end]

[blank_start]Allodynia[blank_end] is a condition whereby an individual experiences pain in response to a stimulus that would not normally provoke the sensation of pain.

[blank_start]Hyperalgesia[blank_end] Increased sensitivity to painful stimuli [blank_start]Allodynia[blank_end] Pain caused by usually non-painful stimuli

The grey matter of the spinal cord is split into ten separate sections called the [blank_start]laminae of Rexed[blank_end]

Label the various locations of referred pain.

[blank_start]Viscerosomatic[blank_end] pain is a sharp and well-localised type of pain that occurs when an inflamed organ comes into contact with the body wall. Think of appendicitis,; it is first visceral pain that refers to the umbilicus but then as it enlarges it comes into contact with the body wall and the pain shifts to the right iliac fossa.

Nociception and pain are two different things: [blank_start]Nociception[blank_end] is the sensory nervous system's response to noxious stimuli [blank_start]Pain[blank_end] is the awareness of suffering One can occur in absence of the other.

Major Nociceptive Tracts: [blank_start]The Spinothalamic Tract[blank_end]: Mainly projects fast fibre (A-delta-fibre) pain and is important in the localisation of painful stimuli [blank_start]The Reticulospinal Tract[blank_end]: Mainly projects slow fibre (C-fibre) pain and is important in the alertness and emotional responses to pain. Our fear of pain arises from this tract.