2 - Somatosensory system 1 Flashcards Preview

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

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

What are the somatic senses?

- Pain
- Temperature
- Pressure
- Stretch
- 2-point discrimination
- Vibration

2

Which receptors detect pain?

Nociceptors

3

Which receptors detect temperature?

Thermoreceptors

4

Which receptors detect pressure on skin?

Pacinian corpuscles

5

Which receptors detect stretch?

Ruffini nerve endings

6

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

Slow adapting, continue to fire APs as long as stimulus continues
- Nociceptors
- Muscle spindle
- Golgi tendon

7

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

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

8

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

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

9

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

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

10

What is the 1st law of the somatosensory system?

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

11

What is the 2nd law of the somatosensory system?

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

12

What is the 3rd Law of the somatosensory system?

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

13

Which order neurone in the somatosensory system is the receptor?

1st order neurone

14

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

2nd order neurone
Thalamus

15

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

3rd order neurone

16

Receptors of the somatosensory system have cell bodies...

in the dorsal root ganglion of spinal cord

17

What factors affect the acuity of a somatic receptor?

- Receptive field
- Density of receptors
- Lateral inhibition

18

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

- Hands
- Face

19

What is the relationship between acuity and receptive field?

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

20

What is meant by lateral inhibition?

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

21

How do inhibitory neurones help us localise a stimulus?

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

22

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

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

23

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

Lower limb + genitals

24

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

Trunk + Upper limb

25

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

Face

26

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

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

27

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

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

28

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

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

29

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

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

30

Describe the area of the primary motor cortex:

Pre-central gyrus, frontal lobe