somatosenses/ somatosensory system

Question 1

what is the somatosensory system

Answer 1

A network of neuronal structures in the brain that produces the perception of touch, temperature, and pain

It consists of organic senses (provides info and pleasant or unpleasant sensations)

and consists or proprioception and kinaesthesia (body position and movement)

and consists of cutaneous sense (skin senses)

Question 2

what does our skin contain?

Answer 2

2 different sensory receptors
encapsulated somatosensory receptors
free nerve endings

Question 3

encapsulated somatosensory receptors, touch receptors

Answer 3

touch receptors are called mechanoreceptors

they respond to vibrations and changes in pressure.

the movement of dendrites of these receptors causes ion channels to open changing receptor potential causing an AP and SIGNAL BEING TRANSFERRED ALONG AN AXON (VIA LARGE MYELINATED AB FIBRES resulting in high conduction velocity)

Question 4

free nerve endings- perception of temp?

Answer 4

thermoreceptors have free nerve endings
we have warm and cold thermoreceptors.

warm use unmyelinated c fibres

cold use same as warm and lightly myelinated A fibres

Question 5

free nerve endings- perception of pain

Answer 5

nociceptors

pain is conveyed via lightly myelinated A fibres and unmyelinated C fibres.

types of nociceptors= mechanical, thermal, chemical (histamine), polymodal

Question 6

somatosensory cortex

Answer 6

consists of primary (s1) and secondary (s2)

volume of somatosensory cortex is not proportionate to body surface e.g. fingers and stomach

Question 7

chronic pain=

Answer 7

involves pathways to the prefrontal cortex