2 - Somatosensory system 1 Flashcards Preview

Semester 5 - Neuro > 2 - Somatosensory system 1 > Flashcards

Flashcards in 2 - Somatosensory system 1 Deck (30)
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1
Q

What are the somatic senses?

A
  • Pain
  • Temperature
  • Pressure
  • Stretch
  • 2-point discrimination
  • Vibration
2
Q

Which receptors detect pain?

A

Nociceptors

3
Q

Which receptors detect temperature?

A

Thermoreceptors

4
Q

Which receptors detect pressure on skin?

A

Pacinian corpuscles

5
Q

Which receptors detect stretch?

A

Ruffini nerve endings

6
Q

What is meant by a tonic receptor? Give an example:

A

Slow adapting, continue to fire APs as long as stimulus continues

  • Nociceptors
  • Muscle spindle
  • Golgi tendon
7
Q

What is meant by a phasic receptor? Give an example:

A

Fast adapting, freq of APs decrease over time even if stimulus is unchanged
All mechanoreceptors:
- Pacinian corpuscle
- Baroreceptors

8
Q

What type of receptors are fast adapting? What does this mean?

A

Phasic receptors
Freq. of APs decrease over time even if stimulus is unchanged = we can adapt to certain sensory stimuli
ie Pacinian corpuscles

9
Q

What type of receptors are slow adapting? What does this mean?

A

Tonic receptors
Freq. of APs continues as long as stimulus continues = we cannot adapt to certain stimuli ie pain
ie Nociceptors

10
Q

What is the 1st law of the somatosensory system?

A

1st order neurone is receptor, and has cell body in dorsal root ganglion of spinal cord

11
Q

What is the 2nd law of the somatosensory system?

A

2nd order neurone crosses the midline and passes up to thalamus

12
Q

What is the 3rd Law of the somatosensory system?

A

3rd order neurone passes from thalamus to sensory cortex via corona radiata

13
Q

Which order neurone in the somatosensory system is the receptor?

A

1st order neurone

14
Q

Which order neurone in the somatosensory system crosses the midline? Where does this neurone end-synapse?

A

2nd order neurone

Thalamus

15
Q

Which order neurone in the somatosensory system delivers sensory information to the cortex?

A

3rd order neurone

16
Q

Receptors of the somatosensory system have cell bodies…

A

in the dorsal root ganglion of spinal cord

17
Q

What factors affect the acuity of a somatic receptor?

A
  • Receptive field
  • Density of receptors
  • Lateral inhibition
18
Q

In which parts of the body do somatic receptors have high acuity? (^density, low receptive field)

A
  • Hands

- Face

19
Q

What is the relationship between acuity and receptive field?

A

Acuity is inversely proportional to the size of the receptive field
- ^ acuity if small receptive field

20
Q

What is meant by lateral inhibition?

A

The primary neurone which is MOST stimulated by the stimulus can inhibit lateral neurones, allowing localisation of the stimulus

21
Q

How do inhibitory neurones help us localise a stimulus?

A

Lateral inhibition
The primary neurone which is MOST stimulated by the stimulus can inhibit lateral neurones, allowing localisation of the stimulus

22
Q

Why is there a large representation of the face and hands on the cortical homunculus?

A

Representation of each body part is proportional to the density of receptors in that region
^density receptor on face/hands = ^representation

23
Q

Which areas of the body are represented on the medial aspect of the cortical homunculus?

A

Lower limb + genitals

24
Q

Which areas of the body are represented on the upper lateral aspect of the cortical homunculus?

A

Trunk + Upper limb

25
Q

Which areas of the body are represented on the lower lateral aspect of the cortical homunculus?

A

Face

26
Q

Describe the area of the brain responsible for the motor function of swallowing:

A

Lower lateral aspect of the pre-central gyrus (primary motor cortex)
- Frontal lobe

27
Q

Describe the area of the brain responsible for the motor function to bend the knee:

A

Medial aspect of pre-central gyrus (primary motor cortex)

- Frontal lobe

28
Q

Describe the area of the brain responsible for detecting a change in pressure on the feet:

A

Medial aspect of the post-central gyrus (primary somatosensory cortex)
- Parietal lobe

29
Q

Describe the area of the brain responsible for detecting a change in temperature in the hands:

A

Middle lateral aspect of the post-central gyrus (primary somatosensory cortex)
- Parietal lobe

30
Q

Describe the area of the primary motor cortex:

A

Pre-central gyrus, frontal lobe