Thermal and Nociceptors

Question 1

Thermal Afferents encode what?

Answer 1

Temperature changes sensed by the skin

Question 2

What is normal skin temperature?

Answer 2

34º C

Question 3

What is the primary receptor for Thermal receptors and where are they located?

Answer 3

Free nerve endings located in the dermal layer of the skin

Question 4

Cold afferents respond to what range of temperature changes?

Answer 4

10-33º C

Question 5

Heat afferents respond to what range of temperature changes?

Answer 5

32-45º C

Question 6

Cold afferents travel over what fiber types?

Answer 6

Type A-𝛿 and C fibers

Question 7

Heat afferents are restricted to what fiber type?

Answer 7

Type C

Question 8

In regards to Thermal receptor fibers, where can the highest concentration of the A-𝛿 and C fibers be found?

Answer 8

Near the midline

Question 9

True or False:

Thermoreceptors are classified by their response to cold or heat…they are seperate receptors with seperate responses

Answer 9

True

Question 10

Nociceptors (pain) occurs where in the body?

Answer 10

1. ) Dermal layers of the skin
2. ) Many deep tissues including muscles and joints

Question 11

What is the primary receptor for Nociceptors?

Answer 11

Free nerve endings

Question 12

What is the primary stimulus for nociceptors?

Answer 12

Mechanical damage to tissue, either by temperature extremes or distruction of tissue (mechanical, chemical)

Question 13

Name the 3 Afferent categories of Nociceptors

Answer 13

1. ) Cutaneous Nociceptive Afferents
2. ) Muscle and Joint Nociceptive Afferents
3. ) Visceral Nociceptive Afferents

Question 14

What fiber type/s are Cutaneous Nociceptive Afferents classified as?

Answer 14

1. ) A-𝛿 Mechanoreceptive Nociceptor
2. ) A-𝛿 Mechanothermal Nociceptor
3. ) C-Polymodal Nociceptors

Question 15

What are the 3 fiber types assoicated with Nociceptors?

Answer 15

1. ) A-𝛿 Mechanoreceptive Nociceptor
2. ) A-𝛿 Mechanothermal Nociceptor
3. ) C-Polymodal Nociceptors

Question 16

Muscle and Joint Nociceptive Afferents have what fiber type/s associated with them?

Answer 16

1. ) A-𝛿 Mechanoreceptive Nociceptor
2. ) A-𝛿 Mechanothermal Nociceptor
3. ) C-Polymodal Nociceptors

Question 17

When dealing with Muscle and Joint Nociceptive Afferents A-𝛿 fiber components are activated by what? What is this term?

Answer 17

Muscle Stretch or Contraction

–Ergoreceptive

Question 18

When dealing with Muscle and Joint Nociceptive Afferents C fibers are activated by what?

Answer 18

Intense Mechanical or Chemical Stimuli

—Ischemic muscle pain

Question 19

Joint receptors are activated by what?

Answer 19

Intense pressure and movement

Question 20

What are Joint receptors sensitized by?

Answer 20

Inflammation

Question 21

High background firing occurs when?

Answer 21

In the presence of inflammation

Question 22

Visceral Nociceptive Afferents are which fiber type?

Answer 22

C fibers similar to C polymodal nociceptors

Question 23

Visceral Nociceptive Afferents relay what?

Answer 23

Poorly localized and referred information

Question 24

Visceral Nociceptive Afferents are stimulated how?

Answer 24

By twisting, distention (enlarged), and/or inflammation

Question 25

A-𝛿 Mechanorecetive Nociceptors are characterized by having *high/low* threshold stimulation with *large/small* receptive areas?

Answer 25

They have **High** threshold for stimulation with **Small** receptive areas

Question 26

A-𝛿 mechanoreceptive nociceptors have small receptive areas where \_\_\_% lie within the facial planes?

Answer 26

20%

Question 27

What is the Primary Stimulus when dealing with A-𝛿 Mechanoreceptive is what?

Answer 27

Sharp pain allowing for discrimination between sharp and dull

Question 28

A-𝛿 Mechanoreceptive nocioceptors are sensitized by what?

Answer 28

Intense heat that results in burn hyperalgesia

Question 29

A-𝛿 Mechanothermal nociceptors are maximally responive to what temperatures?

Answer 29

45-53º C But also respond to temperatures \>20º C

Question 30

A-𝛿 Mechanothermal nociceptors are responsible for what?

Answer 30

The first pain from intense themral stimuli as well as intense mechanical stimuli

Question 31

C-polymodal nociceptors are the majority of _______ receptors and are which type of fibers?

Answer 31

Majority of **Cutaneous receptors** and are Free nerve endings

Question 32

What are C-polymodal nociceptors activated by?

Answer 32

1. ) Thermal (\<10º C and \<50ºC) 2. ) Mechanical (crush) 3. ) Chemical (histamine release from tissue damage)