Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NE2 > Sensory Physiology > Flashcards

Sensory Physiology Flashcards

1
Q

How are peripheral nerves classified

A

By its contribution to an action potential (A, B, C waves) and by its physical characteristics (diameter, myelin thickness, conduction velocity).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How are conduction velocity and action potential related?

A

Conduction velocity determines a fibers contribution to the compound action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Meissner corpuscle receptor type and sensation

A

Glaborous skin
Low threshold, rapidly adapts.
Touch/vibration < 100 Hz.
Easily activated because of such a low threhold.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Pacinian corpuscle receptor type and sensation

A

Hairy and hairless skin
Low threshold, rapidly adapting
Rapid indentation of the skin
100-400 Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Ruffini corpuscle receptor type and sensation

A

Hairy and hairless skin
Low threshold, slowly adapting
Stretch magnitude and direction
Touch, pressure, proprioception

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Merkel cell receptor type and sensation

A

Glaborous
Low threshold, slowly adapting
Pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Hair follicle receptor type and sensation

A

Rapidly and slowly adapting

Motion and directionality across skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Tactile free-nerve ending type and sensation

A

High threshold, slowly adapting

Pain and temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Compare the receptive fields in the fingertips vs. the back

A

Fingertips have a high density of small receptive fields, whereas the back has large receptive fields. Discriminative touch is easier to do then you have a high density, small receptor field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are convergence and receptive fields related?

A

Convergence can cause you to feel only 1 sensation in 2 receptive neurons. The number of neurons doesn’t necessarily predict the size of the receptive field.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the 2 point discrimination test look for?

A

Test is a diagnostic tool for peripheral sensory deficiencies.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does the somatosensory area I do? Where is it? What happens to the somatotopic map?

A

Primary sensory cortex in the post-central gyrus. Cutaneous, crude touch. Integrates position, size, shape. The somatotopic representation is kept.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What does the somatosensory area II do? Where is it? What happens to the somatotopic map?

A

Compares between objects and different tactile sensations. Has a role in whether something becomes a memory, but does not do the emotional part of pain. Located in the wall of Sylvian fissure. Receives input from S1. Less maintained somatotopic map.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the parieto-temporal-occipital association area do?

A

High-level interpretation of sensory inputs. Analyzes spatial coordinates of self. Identifies objects.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the law of projection?

A

Important to amputees. Stimulation to the point in the cerebral cortex, or anywhere on the pathway, will project the sensation to the location of the receptor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is pain?

A

Sensory and emotional experience assctd. w/ actual or potential tissue damage. It is the FEELING of pain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is nociception?

A

The actual process of neurally encoding noxious stimuli.

Note: encoding consequences may be autonomic (HTN). The pain sensation is not always present.

18
Q

What is hypersensitivity?

A

Increase in the responsiveness of neurons more related to pain and/or recruitment of a response to normally subthreshold inputs.

19
Q

What is hyperaesthesia?

A

Increased sensitivity to stimulation, EXCEPT special senses. A heightening of any sense makes this different from hypersensitivity, which is more related to pain.

20
Q

What is hyperalgesia?

A

abnormally increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves and can cause hypersensitivity to stimulus.

21
Q

What is allodynia?

A

Pain due to a stimulus that doesn’t usually cause pain. Ex. laying sheets on sunburnt skin

22
Q

Describe A delta fibers. Size, speed, what they carry, location of pain, and receptive field?

A 
Size: 2-5 mm, myelinated
Speed: 5-40 m/s, faster than C fibers
Carry nociceptive mechanical or mechanothermal specific nociceptors
Small receptive fields
Precise localization of pain
23
Q

Describe C fibers. Size, speed, what they carry, location of pain, and receptive field?

A

Size: 0.4-1.2 mm, unmyelinated
Speed: 0.5-2 m/s
Activated by high-intensity mechanical, chemical, and thermal stimulation and carry info from polymodal nociceptors
Larger receptive area, less precise pain localization

24
Q

What is the biphasic response to pain?

A

The combination of sensations elicited initially by A delta then by C-fibers. It is why we feel a sharp, localized pain at first, then the pain becomes dull and less localized.

25
Q

What are the 3 general modalities?

A

Mechanical
Chemimcal
Thermal

26
Q

Mechanical modality?

A

Responds to moderate pressure w/ a blunt object

27
Q

Chemical modality?

A

Responds to endo or exo chemicals (pro-inflammatory mediators, acids, capsaicin)

28
Q

Thermal modality?

A

Responds to noxious heat and cold

29
Q

What is the transient receptor potential (TRP) family?

A

A family of receptor ligand gated nonselective cation channels. Sense lots of stuff: pH, inflammatory mediators, heat, cold, exo chemicals.

30
Q

What does activation of TRPV1 lead to?

A

Leads to AP firing and release of neuropeptides (CGRP, substance P)

31
Q

What does sustained activation of TRPV1 do?

A

Leads to increased CGRP & SP ->vasodilation and immune response -> proinflammatory mediator release -> positive feedback loop w/ potnetiation of the TRVP1 channel

32
Q

What kinds of pain are involved with TRVP1?

A 
Migraine
Dental
Cancer
Inflammatory
Neuropathy
Visceral pain
osteoarthritis
33
Q

What activates TRPA1?

A

Allyl isothiocyanate in mustard oil, wasabi, horseradish. *Anesthetics have paradoxical pro-nociceptive effects by acting thru TRPA1

34
Q

What activates TRPM8?

A

Innocuous cooling (26-15 Celcius) and noxious cold (15-8 Celcius)

35
Q

What inflammatory pain states are involved with TRPA1?

A 
Allergic contact dermatitis
Chronic itch
Painful bladder syndrome
Migraine
IBC
Pancreatitis
36
Q

How does gate theory work?

A

With strong pain, the C fiber stops inhibition of the pathway and pain signals are sent to the brain (“open”)

Activate A beta fiber which will synapse on the inhibitory neuron and activate it.

Inhibitory neuron will then release Glycine, which will decrease the painful stimulus by inhibiting the secondary neuron of the nociceptive pathway.

37
Q

How does the descneding inhibition pathway work?

A

PAG is activated by opiates, EAA, and cannabinoids. The descending projections go to locus ceruleus (NE) and raphe nuclei (5HT). NE and 5HT goes to the dorsal horn to activate inhibitory interneurons that release opiates. Opiates bind to mu receptors on a C fiber to reduce SP from the C fiber. Reduces nociception.

38
Q

2 actions of descending serotenergic and noradrenergic neurons?

A
  1. Activate local interneurons to help decrease the pain

2. Suppress spinothalamic projection neurons so pain doesn’t have a chance to be felt

39
Q

What do peptidergic nociceptors express and how many are there?

A

Express neuropeptides (SP, CGRP)
Response to nerve growth factor
Most visceral afferents are peptidergic; contributes to visceral pain syndromes
Chronic inflammation upregulates neuropeptides

40
Q

What do non-peptidergic nociceptors do and how many are there?

A

Do not express SP or CGRP. Respond to glial-derived neurotrophic factor. Half of cutaneous afferents are non-pepti, other half are pepti. Involved in somatic chronic pain, like DM neuropathy

41
Q

What does the insular cortex do in regards to pain?

A

Interprets the pain as uncomfortable. Damage to this causes asymbolia (feel pain, but indifferent to it)

42
Q

What does amgydala do?

A

Important in emotional component of pain

NE2 (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions