05b: Somatosensation and Pain Flashcards Preview

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Flashcards in 05b: Somatosensation and Pain Deck (52):
1

List various sensory receptor types, from deep to superficial

1. Pacinian corpuscles
2. Ruffini's corpuscles
3. Merkel's disks
4. Meissner's corpuscles
5. Free nerve endings

2

T/F: All classes of cutaneous sensation are represented among the free nerve endings.

True

3

Two-point discrimination smaller on (fingertips/back)

Fingertips

4

Central neurons, (like/unlike) receptors, use (X) mechanism for transmitting info about a stimulus intensity.

Like;
X = frequency coding

5

(Primary afferent fibers/central neurons) have complex receptive fields. Explain.

Central neurons;

Lateral inhibition (sharpens transmission of sensory messages)

6

Detailed topographical representation of (ipsi/contra)-lateral body forms within thalamus.

Contralateral

7

Cutaneous afferents are found within (X) regions of thalamus.

X = posterior

8

T/F: Pain is always subjective.

True

9

T/F: Pain is always unpleasant.

True

10

T/F:Pain is activity induced in nociceptor/nociceptive pathway by noxious stimulus.

False - pain is psych state

11

T/F: Noxious stimulus is defined as one that produces tissue damage.

True

12

List 3 classes of nociceptors.

1. Mechanical
2. Thermal
3. Polymodal

13

Mechanical nociceptors respond to (X) stimuli and have (small/large) receptive fields.

X = crushing P
Large

14

Thermal nociceptors respond to (X) stimuli and have (small/large) receptive fields.

X = temperatures above 45C or below 15C

Large

15

Polymodal nociceptors respond to (X) stimuli and have (small/large) receptive fields.

X = both high threshold mechanical and thermal stimulation;

Large

16

(X) caused by (Y) provide(s) the principal stimulus for nociceptor activation.

X = chemicals;
Y = release from damaged tissue (into extracellular fluid)

17

List some "pain related molecules". Star those that sensitize all classes of nociceptors.

1. Bradykinin
2. Substance P
3. Histamine
4. K+
5. Prostaglandins*

18

A noxious stimulus evokes release of (X) from (Y). Be specific.

X = Bradykinin
Y = damaged tissue

19

List effect(s) of bradykinin.

1. Excites nociceptor
2. Increases prostaglandin production
3. Dilates blood vessels

20

You step on a nail. In response to (excitatory/inhibitory) actions of (Y), the nociceptor terminal releases (X).

Excitatory;
X = bradykinin and prostaglandins;
Y = substance P

21

You step on a nail. Effect of Substance P, when released from (X).

X = nociceptor terminal

1. Further sensitizes nerve terminal
2. Increases blood vessel dilation
3. Increases inflammatory response

22

T/F: Similar to other receptors, nociceptors adapt with frequent stimulation.

False - sensitize with frequent stimulation

23

Pain is subserved primarily by which peripheral nerve fiber types?

1. A-delta
2. C

24

In terms of conduction velocity, A-delta are the most rapid of (X) fibers, but the slowest of the (Y) fibers.

X = pain;
Y = A

25

A-delta fibers are distributed in (X) parts of body and carry information about (Y) stimuli.

X = skin and mucous membranes
Y = mechanical and thermal

26

C fibers are distributed in (X) parts of body and carry information about (Y) stimuli.

X = deep tissues and skin
Y = polymodal

27

T/F: C fibers outnumber A-delta fibers in the skin.

True

28

Sharp, stinging painful sensation carried by which type of pain fibers?

A-delta

29

Burning, unpleasant painful sensation carried by which type of pain fibers?

C fibers

30

A-delta fibers synapse in (X), on the dendrites of neurons with somata in Rexed's Laminae (Y). This gives rise to (Z) tract.

X = substantia gelatinosa
Y = 1 and 5
Z = neospinothalamic

31

Neospinothalamic tract terminates in (X). Then signal goes to (Y) cortex.

X = VPL thalamus;
Y = somatosensory cortex

32

C fibers synapse in (X), on the dendrites of (Y), which send info to cells in Rexed's Laminae (Z).

X = substantia gelatinosa
Y = small, excitatory interneurons
Z = 5-8

33

C-fibers use (X) as the NT at their synapse in substantia gelatinosa.

X = Substance P

34

Rexed Laminae (X) give rise to paleospinothalamic tract.

X = 6-8

35

Rexed Lamina 5 neurons, receiving input from (A-delta/C) pain fibers, contribute primarily to (X) tract.

C-fibers;
X = spinomesencephalic

36

T/F: Both neo and paleospinoathalmic tracts are somatotopically organized.

False - paleo is not

37

Paleospinothalamic tract terminates in (X). Then signal goes to (Y) cortex.

X = intralaminal nucleus of thalamus;
Y = cingulate

38

Collaterals from (neo/paleo)spinothalamic tracts contribute to which ascending brainstem tracts?

Both;

1. Spinomesencephalic
2. Spinoreticular tract

39

Spinomesencephalic tract arises from neurons in lamina (X) and projects to (Y).

X = 1 and 5
Y = PAG

40

Spinoreticular tract arises from neurons in lamina (X) and projects to (Y) via (Z).

X = 6-8
Y = thalamus
Z = reticular formation

41

WDR, aka (X), neurons are in lamina (Y). They're termed this because of which characteristic?

X = wide dynamic range;
Y = 5

Excited by multimodal/diverse inputs from A-beta, A-gamma, and C fibers

42

WDR neurons activate (X) via (Y) tract.

X = PAG;
Y = spinomesencephalic

43

In addition to receiving pain info from WDR neurons, the (X) receives input from (Y), conveying info on emotional/physio responses to pain.

X = PAG
Y = amygdala, hypothalamus, neocortical areas

44

PAG neurons normally (stimulate/inhibit) nucleus raphe magnus (NRM).

Inhibit

45

Enkephalin, released by (X), has (stimulatory/inhibitory) effect on (Y), thus activating (Z).

X = PAG neurons
Inhibitory;
Y = other PAG neurons
Z = NRM cells

46

Descending serotonergic (PAG/NRM) inputs (excite/inhibit) (X) interneurons in (brainstem/SC).

NRM;
Excite;
X = enkephalinergic
SC

47

Release of enkephalin in SC has which effect(s)?

Inhibits:
1. Afferent pain fiber activity
2. WDR activity

48

Ideal way to alleviate pain is to:

Treat underlying disease

49

Pharmacological treatment of pain is possible via:

1. NSAIDS
2. Opioids

50

NSAIDS mechanism

Inhibit cyclooxygenase

51

Cyclooxygenase involved in which reaction?

Conversion of arachidonic acid to prostaglandin

52

Give examples of commonly used NSAIDS

1. Ibuprofin
2. Aspirin
3. Acetaminophen