Test 2 - Lecture 2 (Somatosensory System)

Question 1

the capability to localize a stimulus is limited to…

Answer 1

the area of individual receptive fields

Question 2

the capability to distinguish between two separate stimuli is limited by…

Answer 2

the area of individual receptive fields

Question 3

_________ is used to preserve identification of the location of peripheral sensory information

Answer 3

somatotopic mapping

Question 4

peripheral somatosensory neurons are located in the

Answer 4

dorsal root ganglia

pseudo-unipolar

Question 5

somatosensory system is ______

Answer 5

multimodal, consisting of various receptors and processing centers

Question 6

A-alpha (peripheral fibers)

Answer 6

large diameter, heavy myelin sheath (fast conducting)

also considered “type 1”

Question 7

A-beta (peripheral fibers)

Answer 7

medium diameter, myelinated

also considered “type 2”

Question 8

C (peripheral fibers)

Answer 8

unmyelinated (slowest conducting )

Question 9

the largest myelinated fibers convey

Answer 9

proprioceptive information

Question 10

the A(alpha) and A(beta) fibers convey

Answer 10

mechanosensory information from the skin

Question 11

the smaller A(gamma) and unmyelinated C fibers convey

Answer 11

thermal information and pain

Question 12

population coding

Answer 12

increasing stimulus energy will activate an increasing number of receptors within a given receptive field

Question 13

superficial mechanoreceptors

Answer 13

Merkel’s disk (slow adapting) and Meisner’s corpuscle (rapid adapting)

Question 14

merkel discs

Answer 14

slowly adapting: responsive to continually applied pressure

Question 15

meissner’s corpuscles

Answer 15

rapidly adapting: responsive to repetitive, low frequency stimuli (light touch)

Question 16

deep mechanoreceptors

Answer 16

Pacinian (rapid adapting) and Ruffini corpuscles (slow adapting)

Question 17

Ruffini corpuscles

Answer 17

slowly adapting: signaling sustained pressure

Question 18

Pacinian corpuscles

Answer 18

rapidly adapting: signaling changes in pressure (vibrations)

Question 19

slowly adapting mechanoreceptors

Answer 19

stimulus is sustained

maintains signaling throughout the duration that the stimulus is applied

Question 20

rapidly adapting mechanoreceptors

Answer 20

stimulus “on” and stimulus “off”, generally variations in the stimulus intensity
(maintains signaling while the stimulus intensity is changing)

Question 21

enable discrimination of the shape and size of objects pressing against the skin

Answer 21

slowly adapting mechanoreceptors

frequency decreases as the skin being pressed in increases

Question 22

report changing stimulus energy that is caused by vibration or motion or texture

Answer 22

rapidly adapting mechanoreceptors

Question 23

somatotopic mapping and transmission of sensory information from each receptive field via labeled lines contributes to discernment of

Answer 23

points of contact with the object being grasped, the size and shape of objects that we grasp

Question 24

mixed population of receptor types allows discernment of

Answer 24

surface texture, movements of the object relative to the surface of the fingers and hand

Question 25

parallel channels of sensory information provide input to

Answer 25

the sensory cortex, where information is combined to form our perception "of the whole"

Question 26

each follicle is innervated by

Answer 26

a single nerve ending

Question 27

deformation of a hair follicle

Answer 27

induces a generator potential

Question 28

individual cutaneous thermoreceptors respond to either

Answer 28

heat or cold, but not to both (mostly cold)

Question 29

heat receptors (warm to hot)

Answer 29

non myelinated C fibers

Question 30

cold receptors (cool to cold)

Answer 30

myelinated A (gamma) fibers

Question 31

low threshold cold receptors detect

Answer 31

rapid drops in temperature (below 88)

Question 32

high threshold cold receptors/nociceptors detect

Answer 32

rapid drops in temperature in the lower range (32 and below)

Question 33

the most sensitive to changes in temperature are

Answer 33

rapidly adapting to sustained temperature

Question 34

peripheral thermoreceptors

Answer 34

transient receptor potential family of ion channels

Question 35

pain is the perception of

Answer 35

noxious (tissue damaging) stimuli

Question 36

polymodal nociceptors

Answer 36

responsive to a combination of mechanical/thermal/chemical modalities

Question 37

nociceptors have a _________ which prevents their activation by non-noxious stimuli

Answer 37

high stimulus threshold

Question 38

A(gamma) fibers arise from

Answer 38

mechanical and thermal nociceptors (sharp, short lasting, pain)

Question 39

C fibers arise from

Answer 39

polymodal receptors (dull or diffuse pain)

Question 40

first pain

Answer 40

A(gamma) fibers

Question 41

second pain

Answer 41

C fibers

Question 42

somatic pain reports

Answer 42

visceral discomfort and injury (referred pain)

Question 43

relatively few centrally projecting fibers; large receptive field = poor dicrimination

Answer 43

somatic pain (viscera)

Question 44

visceral afferent fibers synapse on

Answer 44

spinal relay neurons

Question 45

viscera causing pain referring its pain to a location on surface

Answer 45

somatic site

Question 46

transient receptor potential (TRP) channels

Answer 46

transduce noxious stimuli can sometimes become sensitized via molecular signaling pathways (@ given stimulus intensity = result will be greater or lesser action potentials)

Question 47

molecules released at a site of injury (bradykinin)

Answer 47

induce inflammatory sensitization by lowering the stimulus threshold for the nociceptive receptors

Question 48

hyperalgesia

Answer 48

sensitization, leading to a perception that the stimulus is MORE painful

Question 49

analgesia

Answer 49

desensitization, leading to a perception that the stimulus is LESS painful

Question 50

primary nociceptors

Answer 50

peripheral sensitization or desensitization of the receptors to the noxious stimulus

Question 51

secondary nociceptors

Answer 51

central sensitization or desensitization of synaptic transmission of peripheral afferent signals arising from nociceptors to the second order relay neurons

Question 52

released chemicals that sensitize adjacent nociceptors

Answer 52

potassium, bradykinin, histamine, serotonin, leukotrienes, prostaglandins, cytokines, and substance P

Question 53

released chemicals that directly activate nociceptors

Answer 53

hydrogen, serotonin, bradykinin, histamine

Question 54

neuropeptides that sensitize or activate surrounding nociceptors

Answer 54

substance P and calcitonin gene-related peptide

Question 55

neurogenic inflammation is caused by

Answer 55

substance P and calcitonin gene-related peptide (CGRP)

Question 56

mechanical hyperalgesia

Answer 56

region of tissue outside of the flare (secondary sensitization)

Question 57

inflammatory flare site

Answer 57

region within the immediate surrounding (primary sensitization)

Question 58

an increased stimulus threshold of the peripheral nociceptors will produce

Answer 58

primary analgesia

Question 59

restraints upon synaptic transmission at the second order relay neuron within the dorsal horn will produce

Answer 59

secondary analgesia

Question 60

analgesia is

Answer 60

reduced sensitivity to a painful stimulus

Question 61

allondynia

Answer 61

pain due to a stimulus that does not normally provoke pain

Question 62

central pain

Answer 62

pain initiated or caused by a primary lesion or dysfunction within the CNS

Question 63

neuralgia

Answer 63

pain in the distribution or a nerve or nerves

Question 64

neurogenic pain

Answer 64

pain initiated or caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or CNS