01 structure function of peripheral sensory receptors

Question 1

Examples of each category of sensory receptors:

1. Exteroreceptive
2. Proprioceptive
3. Interoceptive

Answer 1

1. (external world)
   - ex. mechano-, thermo-, nociceptors
2. muscle length, tension, joint angle
   - ex. muscle spindles, golgi tendon organs
3. internal organs
   - ex. baroreceptors

Question 2

Neuron types by conduction velocity

Answer 2

1. Large myelinated:
   - A alpha–muscle spindles
   - A beta–light touch, vibration, pressure
2. Thin myelinated:
   - A delta–fast pain, cold
3. Unmyelinated:
   - C fibers–slow pain, warmth

Question 3

Compound Action Potential

Answer 3

A clinical diagnostic tool to detect nerve damage. Use electrodes to measure nerve conduction/damage.

Diagnose:

• nerve entrapment
• trauma
• peripheral neuropathies

Question 4

Rapid vs Slowly adapting response for receptor terminals, and example stimuli

Answer 4

• Rapid: constant stimulus soon becomes unnoticeable–impact, motion of objects
• Slowly: stimulus remains noticeable–pressure, shape of objects

Question 5

List mechanoreceptor types in skin (5)

Answer 5

1. Merkel disks
2. Meissner’s corpuscles
3. Ruffini corpuscles
4. Pacinian corpuscles
5. Hair follicle receptors

Question 6

Merkel disks:

• location
• sense type
• slow/rapid adapting
• neuron myelination type

Answer 6

• superficial
• fine touch, 2 point discrimination, sustained pressure
• slow adapting
• A beta

Question 7

Meissner’s corpuscles:

• location
• sense type
• slow/rapid adapting
• neuron myelination type

Answer 7

• superficial
• fine touch+2 point discrimination (edges of objects), low frequency vibration
• rapid adapting (you stop feeling your clothes)
• A beta

Question 8

Ruffini corpuscles

• location
• sense type
• slow/rapid adapting
• neuron myelination type

Answer 8

• deep
• pressure, shape of objects
• slow adapting
• A beta

Question 9

Pacinian corpuscles

• location
• sense type
• slow/rapid adapting
• neuron myelination type

Answer 9

• deep
• pressure, high frequency vibration
• rapid adapting (stop feeling one’s clothes)
• A beta

Question 10

Hair follicle receptors

• location
• sense type
• slow/rapid adapting
• neuron myelination type

Answer 10

• hair follicle
• sense hair movement
• rapid
• A beta or A delta

Question 11

Braille: which mechanoreceptors used?

Answer 11

-Merkel and Meissner’s. (fine touch)

Question 12

Temperature receptors:

-myelination types

Answer 12

• Cold: A delta, thinly myelinated

- Warm: C fibers, no myelination

Question 13

Nociceptor types

• conduction speed
• type of pain
• myelination type
• slow/rapid adapting

Answer 13

1. Fast (A-mechanoreceptors)
   - Sharp intense pain, easily localized
   - A delta, thinly myelinated
   - slow adapting
2. Slow (C-polymodal nociceptors)
   - Dull aching pain, difficult to localize
   - C fibers, no myelination
   - slow adapting