Week 6 - Lecture 1 - Introduction to somatosensory nervous system Flashcards Preview

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Flashcards in Week 6 - Lecture 1 - Introduction to somatosensory nervous system Deck (12)
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1
Q

in the brain, nerve impulses are required for

A

sensation (awareness of stimulus)

perception (interpretation of meaning of stimulus)

2
Q

Classifcation of somatosensory stimulus is based on

A

type of stimulus
location in body
structural complexity

3
Q

mechanoreceptors

A

activated by mechanical forces ( receptor stretching - membrane permeability change )

  • stretch receptors of muscles
  • skin receptors - respond to touch, pressure, vibration, and stretch
4
Q

Thermoreceptors

A

sensitive to changes in temperature

  • cold receptors (10-40 degrees celsius) in superficial dermis
  • heat receptors (32-40 degrees) ; in deeper dermis
  • outside those temperature ranges - nociceptors activated - pain
5
Q

nociceptors

A

sensitive to pain-causing stimuli (eg. extreme heat or cold, excessive pressure, inflammatory chemicals )

6
Q

Exteroreceptors

A

respond to stimuli arising outside the body
receptors in skin for touch, pressure, pain and temperature
present in most special sense organs

7
Q

interoreceptors (visceroreceptors)

A

respond to stimuli arising in internal viscera and blood vessels

sensitive to chemical changes, tissue stretching and temperature changes of these organs

sometimes cause discomfort but usually we are unaware of their workings

8
Q

proprioceptors

A

respond to stretch in skeletal muscles, tendons, joints, ligament, and connective tissue coverings of bones and muscles
inform brain of one’s movements and position

9
Q

Nerve fibre types

A

Type A : largest, myelinated, rapid transmission

  • Type A alpha and beta : may promote inhibitory effects to diminish pain sensation
  • Type A delta : pressure, touch, cold, heat, pain

Type B : smaller than A, myelinated, slower conduction
- transmitted by cutaneous and subcutaneous mechanoreceptors

Type C : smallest, unmyelinated, slowest
- transmitted by warm -hot, mechanical, chemical, temperature induced pain

10
Q

Somatosensory processing

A

primary processing in the thalamus
processing refined in the PSC
interpretation in the somatosensory association areas

11
Q

five major somatosensory system modalities

A
discriminative touch 
proprioception (body position and motion) 
Nociception (pain and itch) 
temp
visceral function
12
Q

Acuity

A

ability to locate the site of initiation