Exam #6: Introduction to Sensory Flashcards Preview

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Flashcards in Exam #6: Introduction to Sensory Deck (35):
1

Define proprioceptor.

Receptors that provide a sense of self i.e. information about joint angles, muscle length, and muscle tension

2

Define adequate stimulus.

Under normal circumstances, a receptor is only affected by a certain threshold of a specific stimulus

3

Define nociceptor.

Pain receptor

4

Define sensory modality.

Different types of sensory stimuli e.g. vision, hearing, taste, smell, touch, pain, temperature, itch

5

Define receptive field.

Region of tissue within which a stimulus can evoke a change in the firing rate of a neuron

6

Define graphesthesia & agraphesthesia.

Sense through which figure or numbers drawn on skin are recognized

7

Define sterognosis & asterognosis.

Ability to recognize objects through touch alone

8

What is the difference between a receptor potential & an action potential?

Receptor potential= graded potentials produced by signal transduction of a sensory stimulus

Action potential= depolarization once threshold has been reached

****Receptor potentials of a sufficient strength will trigger action potentials

9

How does the nervous system can code for the "what" of a sensory stimulus?

Labeled line principle= chain of connected neurons from sensory receptor to brain area that perceives the stimulus

10

How does the nervous system can code for the "where" of a sensory stimulus?

Receptive field

11

How does the nervous system can code for the intensity of a sensory stimulus?

1) Increase frequency of nerve firing
2) Increase number of nerves firing

12

How does the nervous system can code for the duration of a sensory stimulus?

On/off signaling with continuous firing during stimulation

13

What is adaptation of a receptor?

When maintained/ constant stimulus leads to a decrease in firing in the associated sensory nerve over time

14

What is the difference between phasic, tonic, rapidly adapting, & slowly adapting? Give an example of somatosensory receptors of each type of adaptation.

Tonic= slowly adapting & signal intensity/ duration of stimulus
- E.g. merkel's disk (detects steady pressure)

Phasic= rapidly adapting, signals onset & offset
- Pacinian corpuscle (detects rapid changes in stimulus)

15

How are nerve fibers classified?

Roman numeral (sensory only) & letter schemes (motor & sensory): I-IV & A-C
- I-III/ A & B are myelinated
- IV/C are NOT myleinated

16

State which type of nerve fibers is fastest & slowest.

Fastest= I/ A-alpha
Slowest= IV/ C

17

Which type of nerve fiber conducts action potentials at 100 m/s, 50 m/s, 20 m/s, 1 m/s?

100= I/Aa
50= II/ Ab
20= III/Ad
1= IV/ C

18

How could you measure spatial resolution in the somatosensory system?

Two-point discrimination test

19

What is "two-point discrimination"? Which areas of the body show the best discrimination? The worst?

Two-point discrimination is a test of tactile acuity
- Good discrimination at lips and finger tips
- Poor on back & calf

20

List the receptors involved in proprioception. What is the difference between these receptors?

- Joint receptors
- Muscle spindles & golgi tendon organs
- Skin tactile receptors

21

What kinds of information are carried by the dorsal column and anterior column systems?

DC/ML=
1) Proprioception
2) Two-point discrimination
3) Vibration

Anterolateral i.e. Spinothalamic=
1) Pain
2) Temperature

22

Where does information in the dorsal column & anterior column cross the midline?

DC/ML= midline in the brainstem--decussation of the medial lemniscus


Anterolateral i.e. Spinothalamic= spinal cord

23

What kinds of deficits are associated with damage to each system, dorsal column and anterior column?

DC/ML= deficits in:
1) Proprioception
2) Two-point discrimination
3) Vibration

Anterolateral i.e. Spinothalamic= deficits in:
1) Pain
2) Temperature

24

What is the location of the somatosensory cortex? How is the somatosensory cortex organized?

- Parietal lobe (post-central gyrus)
- Broadmann 3,1,2

Medial= foot, leg, & genitals
Lateral= face, trunk, arms

25

What type of information is carried by A-alpha nerve fibers?

Alpha-motoneurons

26

What type of information is carried by A-beta nerve fibers?

Touch & pressure

27

What type of information is carried by A-gamma nerve fibers?

gamma motoneurons to muscle spindles

28

What type of information is carried by A-delta nerve fibers?

Touch, pressure, temperature, & fast pain

29

What type of information is carried by B nerve fibers?

Preganglionic ANS

30

What type of information is carried by C nerve fibers?

Slow pain
Postganglionic ANS
Olfaction

31

What type of information is carried by Ia nerve fibers?

Muscle spindle afferents

32

What type of information is carried by Ib nerve fibers?

Golgi tendon organ afferents

33

What type of information is carried by II nerve fibers?

Secondary afferents of muscle spindles
Touch
Pressure

34

What type of information is carried by III nerve fibers?

Touch
Pressure
Fast pain
Temperature

35

What type of information is carried by IV nerve fibers?

Pain
Temperature
Olfaction

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