Physiology Midterm- Sensory Physiology Flashcards Preview

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Flashcards in Physiology Midterm- Sensory Physiology Deck (43):
0

Transducer

Something that converts one form of energy to another
Ie. retina converts light energy to electrical

1

Sensitivity

Ability to localize where stimulus is without looking at it

2

What happens if a sensory neuron does not spike?

No sensation

3

Peripheral receptive field

Specific region of skin which a receptor monitors
-Usually applies to touch receptors

4

Body parts with peripheral receptive fields smallest in area

Fingertips and lips

5

Where are larger Peripheral receptive fields found?

In areas requiring less need for sensitivity, ie. on your back

6

Where is greatest overlap of peripheral receptive fields?

Areas that require greater sensitivity
Fingertips and lips

7

More overlap of peripheral receptive fields= (more/less) sensitivity

More

8

Specific energy

Type of energy that the receptor is most sensitive to

9

How is the stimulation of light receptors always perceived by the brain as?

Light

10

Can other types of energy stimulate a different energy receptor?

Yes
Ie. you can rub your eye(mechanical stimulus) and stimulate the light receptors and perceive light

11

Two point discrimination

Stimulating 2 points on the body to determine the minimum distance apart that the person can tell that there are two stimuli occurring

12

Hyperesthesia

Patient does not have adaptation with sensory stimuli

13

Receptor adaptation

How fast the fiber will accommodate to stimuli

14

What kind of receptors are the fastest adapting receptors?

Touch receptors on skin and hair receptors

15

Slowest adapting receptors

Pressure receptors in carotid artery

16

Labeled lines

Refers to how the receptors are attached to CNS, which tells the brain how to locate where stimulus is coming from

17

Phantom limb

Feeling a sensation in a limb that has been removed and is no longer there

18

What causes phantom limb pain?

Nerve trunks that are still present in the stump that correlate to the part of the limb that has been removed can still be stimulated, causing the brain to perceive a stimulus in the nonexistent limb

19

Generator potential

Depolarization of nerve ending

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What does a generator potential do?

Will cause membrane potential to move toward 0

21

Basic properties of generator potentials

1. They are depolarizations
2. The greater the stimulus, the larger the generator potential
3. Travel by electrotonic conduction
4. They can sum

22

Trigger zone

Region on membrane near the specialized sensory ending where the spike is initiated if threshold is surpassed

23

Voltage clamping

Process by which the general potential remains as long as the stimulus is in contact with the sensory ending

24

What is the generator potential magnitude determined by?

Stimulus intensity (higher stimulus intensity=higher GP)

25

Rhythmic discharge

Several spikes in sequence

26

What causes rhythmic discharge?

As repolarization proceeds to the level of membrane charge the cell is clamped at, you will get another spike

27

What causes faster repetitive rates of spikes?

Larger generator potential

28

Frequency coding

Brain can estimate the intensity of the stimulus you experience by the frequency of firing of the sensory nerve

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What is the rate of discharge measured in

Spikes/sec

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Relationship between intensity of the stimulus and how the brain perceives it

^stimulus intensity, ^generator potential
^generator potential, ^rate of discharge
^rate of spikes, brain perceives as ^intense stimulus

31

How does the CNS know exactly where a stimulus is occurring and how intense it is?

Property of frequency coding combined with the property of labeled lines

32

Classes of receptors

Mechanoreceptors
Thermoreceptors
Chemoreceptors
Nociceptors

33

Pain sensation theories

Specificity theory
Pattern theory

34

Specificity theory

Receptor specific for pain sense
-problem: does not explain what sort of specific energy pain is
-true because nociceptors respond to prostaglandins and kinins that are produced as a result of inflammation due to damaged tissue

35

Pattern theory

Brain sensed pain by the pattern of spike discharge of receptors of various specific energies
-true because if a rate of firing passes a certain threshold it is perceived as pain (Any type of receptor)

36

Gate control of pain

Non-nociceptive sensory fibers branch as they enter the spinal cord and provide IPSP input to pain pathways.
Pain, touch, and temperature information are all carried by the same tract and are in close proximity, allowing the interneurons to attach in this manner

37

Gate control of pain provides evidence for what therapeutic modalities?

TENS (transcutaneous electroneural stimulation)
Acupuncture
Massage
Heat
Cold

38

Referred pain

Sensation of pain in a structure that is not injured. The pain comes from a different structure that is injured

39

Why does referred pain happen?

During fetal development, structures shared the developing ectoderm that later became neural tissue. As development proceeds , the structures separate but still share the same neuronal pool in the spinal cord.

40

Redicular pain

Pain resulting from nerve irritation

41

Example of referred pain

Patients with supraspinatus tendinitis typically also end up with pain in the C5 dermatome

42

Example of redicular pain

Pain down the leg due to bulging disk pressing on nerve trunk