Thermal and Nociceptors Flashcards
Thermal Afferents encode what?
Temperature changes sensed by the skin
What is normal skin temperature?
34º C
What is the primary receptor for Thermal receptors and where are they located?
Free nerve endings located in the dermal layer of the skin
Cold afferents respond to what range of temperature changes?
10-33º C
Heat afferents respond to what range of temperature changes?
32-45º C
Cold afferents travel over what fiber types?
Type A-𝛿 and C fibers
Heat afferents are restricted to what fiber type?
Type C
In regards to Thermal receptor fibers, where can the highest concentration of the A-𝛿 and C fibers be found?
Near the midline
True or False:
Thermoreceptors are classified by their response to cold or heat…they are seperate receptors with seperate responses
True
Nociceptors (pain) occurs where in the body?
- ) Dermal layers of the skin
- ) Many deep tissues including muscles and joints
What is the primary receptor for Nociceptors?
Free nerve endings
What is the primary stimulus for nociceptors?
Mechanical damage to tissue, either by temperature extremes or distruction of tissue (mechanical, chemical)
Name the 3 Afferent categories of Nociceptors
- ) Cutaneous Nociceptive Afferents
- ) Muscle and Joint Nociceptive Afferents
- ) Visceral Nociceptive Afferents
What fiber type/s are Cutaneous Nociceptive Afferents classified as?
- ) A-𝛿 Mechanoreceptive Nociceptor
- ) A-𝛿 Mechanothermal Nociceptor
- ) C-Polymodal Nociceptors
What are the 3 fiber types assoicated with Nociceptors?
- ) A-𝛿 Mechanoreceptive Nociceptor
- ) A-𝛿 Mechanothermal Nociceptor
- ) C-Polymodal Nociceptors
Muscle and Joint Nociceptive Afferents have what fiber type/s associated with them?
- ) A-𝛿 Mechanoreceptive Nociceptor
- ) A-𝛿 Mechanothermal Nociceptor
- ) C-Polymodal Nociceptors
When dealing with Muscle and Joint Nociceptive Afferents A-𝛿 fiber components are activated by what? What is this term?
Muscle Stretch or Contraction
–Ergoreceptive
When dealing with Muscle and Joint Nociceptive Afferents C fibers are activated by what?
Intense Mechanical or Chemical Stimuli
—Ischemic muscle pain
Joint receptors are activated by what?
Intense pressure and movement
What are Joint receptors sensitized by?
Inflammation
High background firing occurs when?
In the presence of inflammation
Visceral Nociceptive Afferents are which fiber type?
C fibers similar to C polymodal nociceptors
Visceral Nociceptive Afferents relay what?
Poorly localized and referred information
Visceral Nociceptive Afferents are stimulated how?
By twisting, distention (enlarged), and/or inflammation
A-𝛿 Mechanorecetive Nociceptors are characterized by having high/low threshold stimulation with large/small receptive areas?
They have High threshold for stimulation with Small receptive areas
A-𝛿 mechanoreceptive nociceptors have small receptive areas where ___% lie within the facial planes?
20%
What is the Primary Stimulus when dealing with A-𝛿 Mechanoreceptive is what?
Sharp pain allowing for discrimination between sharp and dull
A-𝛿 Mechanoreceptive nocioceptors are sensitized by what?
Intense heat that results in burn hyperalgesia
A-𝛿 Mechanothermal nociceptors are maximally responive to what temperatures?
45-53º C
But also respond to temperatures >20º C
A-𝛿 Mechanothermal nociceptors are responsible for what?
The first pain from intense themral stimuli as well as intense mechanical stimuli
C-polymodal nociceptors are the majority of _______ receptors and are which type of fibers?
Majority of Cutaneous receptors and are Free nerve endings
What are C-polymodal nociceptors activated by?
- ) Thermal (<10º C and <50ºC)
- ) Mechanical (crush)
- ) Chemical (histamine release from tissue damage)
