Lecture 8: The Perception of Touch

Question 1

3 parts of somatosensory system

Answer 1

1) cutaneous senses
2) proprioception
3) pain perception

Question 2

Cutaneous senses

Answer 2

perception of touch and pain from stimulation of skin

Question 3

Proprioception

Answer 3

ability to sense position of the body and limbs

Question 4

Kinesthesis

Answer 4

ability to sense movement of body and limbs

Question 5

Heaviest organ in body

Answer 5

skin

Question 6

Epidermis

Answer 6

outer layer of skin made up of dead skin cells

Question 7

Dermis

Answer 7

Below epidermis, contains mechanoreceptors for pressure, stretching and vibration

Question 8

Two types of mechanoreceptors located close to surface of skin

Answer 8

1) Merkel receptor

2) Meissner corupuscle

Question 9

2 Functions of Merkel receptor

Answer 9

1) detects when stimulus is present

2) responsible for sensing fine details

Question 10

2 Functions of Meissner corupuscle

Answer 10

1) details when stimulus is applied and when removed

2) responsible for controlling hand-grip

Question 11

Two types of mechanoreceptors located deeper in skin

Answer 11

1) Ruffini cylinder

2) Pacinian corpuscle

Question 12

2 Functions of Ruffini cylinder

Answer 12

1) Fires continuously to stimulation

2) Associated with perceiving stretching of skin

Question 13

Three Functions of Pacinian corpuscle

Answer 13

1) Fires when stimulus is applied and when removed
2) Associated with sensing rapid vibrations and fine texture
3) Good for perceiving vibration

Question 14

Two major pathways in spinal cord from skin to cortex

Answer 14

1) medial lemniscal pathway

2) spinothalamic pathway

Question 15

Medial lemniscal pathway

Answer 15

large fibres that carry proprioceptive and touch information

Question 16

Spinothalamic pathway

Answer 16

smaller fibres that carry temperature and pain information

Question 17

3 measures of tactile acuity

Answer 17

1) two-point threshold (minimum separation between two points)
2) Grating acuity (orientation of the grating on grooved stimulus)
3) raised pattern identification (smallest pattern identifiable)

Question 18

Katz (1925) Two cues for perceiving texture

Answer 18

1) spatial cues (size, shape etc)

2) temporal cues (vibration etc)

Question 19

Haptic perception

Answer 19

use hands to actively explore 3D objects

Question 20

Three types of pain

Answer 20

1) nociceptive
2) inflammatory
3) neuropathic

Question 21

Nociceptive pain

Answer 21

skin, impending damage to skin

Question 22

Inflammatory pain

Answer 22

damage to tissue joints

Question 23

Neuropathic pain

Answer 23

damage to CNS