Physiology Midterm- Sensory Physiology

Question 0

Sensitivity

Answer 0

Ability to localize where stimulus is without looking at it

Question 1

Transducer

Answer 1

Something that converts one form of energy to another

Ie. retina converts light energy to electrical

Question 2

What happens if a sensory neuron does not spike?

Answer 2

No sensation

Question 3

Peripheral receptive field

Answer 3

Specific region of skin which a receptor monitors

-Usually applies to touch receptors

Question 4

Body parts with peripheral receptive fields smallest in area

Answer 4

Fingertips and lips

Question 5

Where are larger Peripheral receptive fields found?

Answer 5

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

Question 6

Where is greatest overlap of peripheral receptive fields?

Answer 6

Areas that require greater sensitivity

Fingertips and lips

Question 7

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

Answer 7

More

Question 8

Specific energy

Answer 8

Type of energy that the receptor is most sensitive to

Question 9

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

Answer 9

Light

Question 10

Can other types of energy stimulate a different energy receptor?

Answer 10

Yes

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

Question 11

Two point discrimination

Answer 11

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

Question 12

Hyperesthesia

Answer 12

Patient does not have adaptation with sensory stimuli

Question 13

Receptor adaptation

Answer 13

How fast the fiber will accommodate to stimuli

Question 14

What kind of receptors are the fastest adapting receptors?

Answer 14

Touch receptors on skin and hair receptors

Question 15

Slowest adapting receptors

Answer 15

Pressure receptors in carotid artery

Question 16

Labeled lines

Answer 16

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

Question 17

Phantom limb

Answer 17

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

Question 18

What causes phantom limb pain?

Answer 18

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

Question 19

Generator potential

Answer 19

Depolarization of nerve ending

Question 20

What does a generator potential do?

Answer 20

Will cause membrane potential to move toward 0

Question 21

Basic properties of generator potentials

Answer 21

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

Question 22

Trigger zone

Answer 22

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

Question 23

Voltage clamping

Answer 23

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

Question 24

What is the generator potential magnitude determined by?

Answer 24

Stimulus intensity (higher stimulus intensity=higher GP)

Question 25

Rhythmic discharge

Answer 25

Several spikes in sequence

Question 26

What causes rhythmic discharge?

Answer 26

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

Question 27

What causes faster repetitive rates of spikes?

Answer 27

Larger generator potential

Question 28

Frequency coding

Answer 28

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

Question 29

What is the rate of discharge measured in

Answer 29

Spikes/sec

Question 30

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

Answer 30

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

Question 31

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

Answer 31

Property of frequency coding combined with the property of labeled lines

Question 32

Classes of receptors

Answer 32

Mechanoreceptors Thermoreceptors Chemoreceptors Nociceptors

Question 33

Pain sensation theories

Answer 33

Specificity theory | Pattern theory

Question 34

Specificity theory

Answer 34

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

Question 35

Pattern theory

Answer 35

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)

Question 36

Gate control of pain

Answer 36

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

Question 37

Gate control of pain provides evidence for what therapeutic modalities?

Answer 37

``` TENS (transcutaneous electroneural stimulation) Acupuncture Massage Heat Cold ```

Question 38

Referred pain

Answer 38

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

Question 39

Why does referred pain happen?

Answer 39

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.

Question 40

Redicular pain

Answer 40

Pain resulting from nerve irritation

Question 41

Example of referred pain

Answer 41

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

Question 42

Example of redicular pain

Answer 42

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