the somatosensory system: pain and thermal sensation

Question 1

how many forms can pain be classed as

Answer 1

3

Question 2

what are the three forms of pain

Answer 2

nociceptive
inflammatory
pathological

Question 3

how can nociceptive pain be described

Answer 3

acute - pin prick

Question 4

how can inflammatory pain be described

Answer 4

prolonged pain - sunburn

Question 5

how can pathological pain be described

Answer 5

damage to nerves or nervous system (no external stimulus)

Question 6

pain sensation in the skin is ____ localised
and can be described as what

Answer 6

well localised
pricking, stabbing or burning

Question 7

pain sensation in the muscle is _____ localised
and can be described as what

Answer 7

poorly localised
aching, soreness/tenderness, cramping, stabbing, burning

Question 8

pain in the viscera is _____localised
and can be described as what

Answer 8

poorly localised (often referred to an area of skin)
dullness, fullness, nausea

Question 9

nociceptive pain begins with the activation of what receptors

Answer 9

nociceptors

Question 10

what type of neurons are nociceptors

Answer 10

specific peripheral primary sensory afferent neurons

Question 11

nociceptors are specific peripheral primary sensory afferent neurons normally activated by _______

Answer 11

intense stimuli such as thermal, mechanical, chemical (noxious or damaging)

Question 12

cell bodies of nociceptors are located where

Answer 12

dorsal root ganglia and trigeminal ganglia

Question 13

what order of neurons are nociceptors

Answer 13

1st order neurons

Question 14

nociceptors are first order neurons that relay info to _____ order neurons

Answer 14

second order neurons

Question 15

nociceptors are first order neurons that relay info to second order neurons where and by what type of transmission

Answer 15

in the CNS and by chemical synaptic transmission

Question 16

what kind of pain is adaptive

Answer 16

nociceptive pain

Question 17

as nociceptive pain is adaptive, what does it serve as

Answer 17

an early warning system to detect and minimise contact with damaging stimuli

Question 18

what pain is hight threshold

Answer 18

nociceptive

Question 19

as nociceptive pain is high threshold, what does this entail

Answer 19

provoked only by intense stimuli that activate nociceptive

Question 20

give 2 properties of nociceptive pain

Answer 20

adaptive
high threshold

Question 21

nociceptive pain has the ability to _________ most other ongoing activites of the nervous system

Answer 21

override

Question 22

what type of pain initiates a withdrawal reflex

Answer 22

nociceptive pain

Question 23

what pain is said to be adaptive AND protective

Answer 23

inflammatory

Question 24

why is inflammatory pain said to be adaptive and protective

Answer 24

caused by activation of the immune system in injury, or infection

Question 25

inflammatory pain is caused by what system

Answer 25

immune system

Question 26

what pain causes pain hypersensitivity

Answer 26

inflammatory pain

Question 27

what pain is associated with allodynia (innocuous stimuli now elicit pain)

Answer 27

inflammatory pain

Question 28

what are the 2 ways that inflammatory pain assists in healing of a damaged body part

Answer 28

discourages physical contact (wound) discourages movement (inflamed joint)

Question 29

what pain is said to be maladaptive with no protective function

Answer 29

pathological pain

Question 30

what is pathological pain a result from

Answer 30

abnormal nervous system

Question 31

how can pathological pain (route of) be described

Answer 31

neuropathic or dysfunctional

Question 32

what happens in the absence of pain

Answer 32

gross damage to the body

Question 33

what is the rare condition that doesn't allow an individual to feel pain

Answer 33

congenital insensitivity to pain (CIP)

Question 34

what is the mutation that causes CIP

Answer 34

loss of function (missense) in gene SCN9A

Question 35

in CIP, the loss of function (missense) in the gene SCN9A encodes what kind of voltage channel

Answer 35

Na+ (Nav1.7)

Question 36

a stimulus to nociceptors opens what type of channel

Answer 36

cation selective channel ion channel

Question 37

stimulus (mechanical, thermal, or chemical) opens cation selective ion channel where

Answer 37

nerve terminal

Question 38

stimulus (mechanical, thermal, or chemical) opens cation selective ion channels in nerve terminal to elicit what

Answer 38

a depolarising receptor potential

Question 39

low threshold units respond to what

Answer 39

low intensity stimuli

Question 40

low threshold mechanoreceptors (LTMs) mediate what (3)

Answer 40

touch, vibration, pressure

Question 41

low threshold thermoreceptros mediate what (5)

Answer 41

cold, cool, indifferent, warm, and hot

Question 42

give an example of high threshold units

Answer 42

nociceptors

Question 43

high threshold units respond to what

Answer 43

high, but now low, intensity stimuli (noxious, potentially damaging)

Question 44

high threshold mechanoreceptors (mechanical nociceptors) respond to what

Answer 44

high mechanical stimuli

Question 45

thermal nociceptors respond to what

Answer 45

extreme degrees of heat >45C <10-15C

Question 46

chemical nociceptors respond to what

Answer 46

substances in tissue (as found in inflammation) e.g. prostaglandins, bradykinin, serotonin, histamine

Question 47

what do polymodal nociceptors respond to

Answer 47

at least 2 forms of painful stimuli

Question 48

in primary sensory afferents what is the decreasing value in this value Aalpa -> Abeta -> Adelta -> C

Answer 48

decreasing diameter conduction velocity

Question 49

Adelta and C fibres are what kind of nociceptors

Answer 49

mechanical/thermal

Question 50

Adelta fibres are mechanical/thermal nociceptors that are _____ myelinated

Answer 50

thinly

Question 51

A delta fibres mediate what kind of pain

Answer 51

first/fast

Question 52

give a reason why C fibres have the lowest conductance rate

Answer 52

unmyelinated

Question 53

C fibres respond to all noxious stimuli so they are said to be....

Answer 53

polymodal

Question 54

C fibres mediate what kind of pain

Answer 54

second or slow

Question 55

what is frequency coding

Answer 55

the rate of an action potential discharge correlates with the intensity of the applied stimulus

Question 56

signalling by nociceptors can be described as what (direction)

Answer 56

bidirectional

Question 57

in the nociceptor, what does the central terminal do

Answer 57

no responsive to environmental stimuli site of Ca2+ dependant transmitter release (glutamate , neuropeptides) targeted by endogenous molecules that regulate activity

Question 58

in the nociceptor, what does the soma allow

Answer 58

major site of protein synthesis - these are delivered to both the central and peripheral terminal

Question 59

in the nociceptor, what does the peripheral terminal do

Answer 59

responds to environmental stimuli site of release of molecules that influence local tissue environment

Question 60

what is a subset of C fibres

Answer 60

peptidergic polymodal nociceptors

Question 61

peptidergic polymodal nociceptors (a subset of C fibres) have what 2 functions

Answer 61

afferent and efferent functions

Question 62

peptidergic polymodal nociceptors (a subset of C fibres) have afferent and efferent functions explain the afferent function

Answer 62

transmit nociceptive info to the CNS via release of glutamate and peptides with the dorsal horn

Question 63

peptidergic polymodal nociceptors (a subset of C fibres) have afferent and efferent functions explain the efferent function

Answer 63

release pro inflammatory mediators from peripheral terminals contributes to neurogenic inflammation

Question 64

what is SP

Answer 64

a peptide

Question 65

what does SP (a type of peptide) cause in neurogenic inflammation

Answer 65

vasodilation and extravasation of plasma proteins release of histamine from mast cells sensitisation of surrounding nociceptors

Question 66

what is CGRP

Answer 66

a peptide

Question 67

what does CGRP induce

Answer 67

vasodilation

Question 68

(neurogenic inflammation) once CGRP induces vasodilation what ensues

Answer 68

hyperalgesia and allodynia ensue

Question 69

neurotransmission in the dorsal horn of the spinal cord what receptors are exhibited in the synaptic cleft during the movement of glutamate, Na, and Ca

Answer 69

NMDA and AMPA

Question 70

what does visecral pain originate from

Answer 70

nociceptors covering tissues

Question 71

visceral pain is perceived at a distance from the ....

Answer 71

affected organ

Question 72

how many neurons are there in the somatic sensory pathway

Answer 72

3 first order, second, third

Question 73

when you feel pressure, or a vibration, when do does the first neuron decussate to the contralateral side

Answer 73

brain stem

Question 74

what 3 structures make up the brain stem

Answer 74

medulla, pons, and mid brain

Question 75

what rout in the spine occurs when activation of the somatic pathway by touch/vibration

Answer 75

dorsal column

Question 76

when there is pain, what pathway do the neurons take

Answer 76

spinothalamic

Question 77

when there is a painful stimulus, where do they neruons decussate

Answer 77

close to the point of entry on the spinal cord

Question 78

where do the second and third order neurons synapse

Answer 78

thalamus

Question 79

where does the third order neuron synapse

Answer 79

point of the brain where the pain is perceived - somatopically mapped

Question 80

what 3 tracts make up the anterolateral system

Answer 80

spinothalamic spinoreticular spinomesencephalic

Question 81

what is the main tract in the anterolateral system for transmitting pain to the cerebral cortex

Answer 81

spinothalamic

Question 82

pain begins where through noxious stimuli (extreme heat etc...)

Answer 82

nociceptors

Question 83

when nociceptors are activated they send a signal through the sinal cord and then to the brain through what system

Answer 83

anterolateral

Question 84

what tract is responsible for the emotional compinent of pain

Answer 84

spinoreticular

Question 85

where does the spinoreticular tract originate

Answer 85

reticular formation

Question 86

where foes the spinomesencephalic tract synapse

Answer 86

periaqueductal grey

Question 87

when the periaqueductal grey is stimulated they can activate a natural what

Answer 87

pain suppression system

Question 88

when they periaqueductal grey is stimulated they can activate a natural pain suppression system through release of what

Answer 88

endogenous opioids -> inhibition of pain signal

Question 89

where is the periaqueductal grey located

Answer 89

in the midbrain of the brainstem

Question 90

what is analgesia

Answer 90

pain reduction

Question 91

what receptors in the PAG rich in

Answer 91

opioid receptors

Question 92

once PAG is activated what structure do they activate in the medulla

Answer 92

raphe nuclei

Question 93

the raphe nuclei is responsible for producing what nurotransmitter

Answer 93

serotonin

Question 94

where does the serotonin go after it is produced from the raphe nuclei

Answer 94

dorsal horn of the spinal cord

Question 95

what occurs once the raphe nuceli send the serotonin to the ventral horn of the spinal cord

Answer 95

inhibits the neurons responsible for transmitting pain signals

Question 96

GATE CONTROL THEORY what neuron is responsible for inhibiting the inhibitory interneuron

Answer 96

a branch off the first order cell body

Question 97

what is responsible for being able to inhibit the neuron that inhibits the inhibitory interneuron to stop it from inhibiting the pain signal

Answer 97

mechanoreceptor Abeta "closes the gate+

Question 98

where does the gate theory occur think about agate to an ice cream shop

Answer 98

substantia gelatinosa