Somatosensory System

Question 1

Somatosensory Receptors are of two basic types:

Answer 1

Free Nerve Endings and Encapsulated Nerve Endings

Question 2

Deformation (or other physical impact on cell)

Answer 2

=> Action potentials in these Receptor cells

Question 3

Free Never Endings

Answer 3

respond to change in Temperature (Thermoreceptors) and pain & itch (Nociceptors)

• Plus many hair follicles have Free Nerve Endings (Follicle Receptors) coiled around them, just under the surface of the skin

Question 4

When hair moved, receptor responds =

Answer 4

Body hair a “reception” mechanism for increasing sensitivity to touch

Question 5

Encapsulated Nerve Endings respond to

Answer 5

1) various types of Touch and
2) Proprioception = internal muscle & organ movement
- Have various, layered, outer coverings that determine which kind of stimulus produces a response

Question 6

Meissner’s

Answer 6

have small Receptive Fields & are fast adapting - so respond to rapid change (e.g slippage)

Question 7

Merkel’s

Answer 7

have small Receptive Fields & are slow adapting - so for detail discrimination (e.g. reading Braille)

Question 8

Pacinians

Answer 8

have large Receptive Fields & are fast adapting - so respond to large scale changes (e.g. bend)

Question 9

Ruffinni’s

Answer 9

have large Receptive Fields & are slow adapting - so respond to sustained, large-scale events (e.g. sit)