Somatosensory System

Question 1

What is proprioception?

Answer 1

Joint and muscle position in space

Question 2

What is nociception?

Answer 2

Pain

Question 3

What is pruriception?

Answer 3

Itch

Question 4

What are the 3 divisions of the somatosensory system?

Answer 4

Exteroceptive division
Proprioceptive division
Enteroceptive division

Question 5

Exteroceptive division - what is it?

Answer 5

Registers infromation from the surface of the body

Cutaneous senses

Question 6

Proprioceptive division - what is it?

Answer 6

Monitors posture, movement

Question 7

Enteroceptive division - what is it?

Answer 7

Closely related to autonomic function

Question 8

The 1st/2nd/3rd order neurone is the primary sensory afferent ?

Answer 8

1st order neurone

Question 9

Which order neurone (1st/2nd/3rd) starts at a peripheral site of the body ?

Answer 9

1st order neurone

Question 10

Cell body of the 1st order neurone will be located where?

Answer 10

Dorsal root ganglion (innervation of limbs, trunk, posterior head)

OR

Cranial ganglia (innervation of anterior head)

Question 11

The 2nd order neurone is located in the CNS. True or false?

Answer 11

True

Question 12

Where is the cell body location of 2nd order neurone?

Answer 12

Dorsal horn of SC or

Brainstem nuclei

Question 13

Where is the cell body location of 3rd order neurone?

Answer 13

Thalamic nuclei

Question 14

Light pressure has a low/high action potential frequency ?

Answer 14

Low

Question 15

What do mechanoreceptors detect?

Answer 15

Touch, pressure, vibration

Question 16

Low threshold units respond to high intensity stimuli. True or false?

Answer 16

False

- low intensity stimuli

Question 17

What do low threshold mechanoreceptors mediate?

Answer 17

Fine discriminatory touch

Question 18

High threshold units respond to nociceptors. True or false?

Answer 18

True

- extremes

Question 19

The greater the diameter of an axon, the lower/higher its internal resistance so the slower/faster the conduction

Answer 19

Greater diameter
Lower resistance
Faster conduction

Question 20

Which primary sensory afferent fibres have the largest diameter?

Answer 20

Proprioceptors

Question 21

Which primary sensory afferent fibres have the smallest diameter?

Answer 21

Temperature
Pain
Itch

Question 22

What is the receptive field ?

Answer 22

The territory from which a sensory unit can be excited.

Question 23

A large receptive field will have low/high density of innervation and low/high acuity ?

Answer 23

Low

Low

Question 24

A small receptive field will have low/high density of innervation and low/high acuity?

Answer 24

High

High

Question 25

Merkel cell neurone complexes is a sensory receptor of hairy/hairless/both skin and has a small/large receptive field ?

Answer 25

Hairless and hairy | Small receptive field

Question 26

Where are merkel cell neurone complexes located?

Answer 26

Areas with high sensory acuity (e.g. fingers)

Question 27

Meissner corpuscle is only ever found in hairy skin. true or false?

Answer 27

False | - only ever found in hairless skin (e.g. fingers)

Question 28

Pacinian corpuscle has a small/large receptive field and detects what?

Answer 28

Large | Deep vibration

Question 29

Name 3 sensory receptors of hairless and hairy skin ?

Answer 29

Pacinian corpuscle Merkel cell neurone complexes Ruffini endings

Question 30

Name 1 sensory receptor of purely hairless skin?

Answer 30

Meissner corpuscles

Question 31

As information is conveyed from one neurone to the next in a sensory pathway, differences in the activity of adjacent neurones are amplified. What is this called?

Answer 31

Contrast enhancement

Question 32

When one neurone is active, it inhibits the activity of its neighbours via inhibitors neurones. What is this called?

Answer 32

Lateral inhibition

Question 33

Somatic information from the anterior head is mediated by which system?

Answer 33

trigeminal system

Question 34

Where is the somatosensory cortex located?

Answer 34

Post central gyrus of the parietal cortex

Question 35

The somatosensory cortex is located immediately anterior/posterior to the central sulcus ?

Answer 35

Posterior

Question 36

The somatosensory system consists of Brodmann areas. True or false?

Answer 36

True

Question 37

How many layers does the somatosensory cortex have?

Answer 37

6 layers

Question 38

What does the homunculus illustrate?

Answer 38

How much cortex is devoted to a particular body part

Question 39

``` Which body part is located at the medial part of the post central gyrus? Trunk Face Upper limb Lower limb ```

Answer 39

Lower limb

Question 40

``` Which body part is located at the lateral part of the post central gyrus? Trunk Face Upper limb Lower limb ```

Answer 40

Face

Question 41

Which area of the brain receives and integrates information from the primary somatosensory cortex ?

Answer 41

Posterior parietal cortex