Somatosensory physiology

Question 1

How is the distribution of somatosensory receptors different from other sensations?

Answer 1

Somatosensory receptors are distributed throughout the body (other systems’ receptors are clustered)

Question 2

What are the four main classes of somatosensory receptors?

Answer 2

tactile
proprioception
thermal sensations
nociceptive (painful)

Question 3

Which two mechanoreceptors sit in the dermal-epidermal boundary?

Answer 3

Meissener’s corpuscles and Merkel’s disks

Question 4

Describe the morphology of Meisseners corpuscles

Answer 4

looping axon terminals that inter-twine supporting cells

Question 5

What do Meisseners corpuscles receive?

Answer 5

low frequency vibrations

Question 6

Describe the morphology or Merkel’s disks

Answer 6

dome structure atop axon terminals

Question 7

What type of sensation do Merkel’s disks receive?

Answer 7

small forms and shapes

Question 8

Describe the morphology of pacinian corpuscles

Answer 8

sensory axon surrounded by fluid filled capsule, onion shaped appearance

Question 9

What type of sensation are pacinian corpuscles responsible for?

Answer 9

high frequency vibrations

Question 10

What type of sensation are ruffini endings responsible for?

Answer 10

pressure

Question 11

What type of sensation are nociceptors responsible for?

Answer 11

noxious/harmful pain

Question 12

Describe the morphology of ruffini ending

Answer 12

nerve terminals intertwined with collagen fibrils

Question 13

Describe the morphology of nociceptors

Answer 13

free nerve endings that penetrate epithelial cells (no morphogological specialisation)

Question 14

Which mechanoreceptors are classed as slow adapting?

Answer 14

Merkel’s disks and ruffini endings

Question 15

Which mechanoreceptors are classed as fast adapting?

Answer 15

Meissener’s corpuscles and pacinian corpuscles

Question 16

Which mechanoreceptors have small receptive fields?

Answer 16

Meissener’s corpuscles and Merkel’s disks

Question 17

Which mechanoreceptor has the smallest receptive field size?

Answer 17

Merkel’s disks

Question 18

Which mechanoreceptors have large receptive fields?

Answer 18

Pacinian’s corpuscles and ruffini endings

Question 19

Which sensation is the most prioritized by the brain (which travels fastest)?

Answer 19

proprioception

Question 20

What is astereoagnosia?

Answer 20

inability to identify objects on basis of touch alone

Question 21

What is neglect syndrome?

Answer 21

body part or visual field is disregarded