4: Physiology - Primary sensory neurons and their modalitiies 2 Flashcards Preview

Neurology Week 2 2018/19 > 4: Physiology - Primary sensory neurons and their modalitiies 2 > Flashcards

Flashcards in 4: Physiology - Primary sensory neurons and their modalitiies 2 Deck (35)
Loading flashcards...
1

Starting at slide 10:

Where is the primary somatosensory area of the brain?

Post-central gyrus

Parietal lobe, just after the central sulcus

2

Which body parts are found at the medial and lateral ends of the sensory strip?

Medially - peripheries i.e upper and lower limbs

Laterally - face, pharynx, abdominal organs

3

What is the sensory homunculus?

Visual representation of how much cortex is devoted to each body part's sensation

i.e massive hands big lips

4

How many layers of cells does the somatosensory area have?

Six

5

In the somatosensory area, neurons corresponding to different parts of the body are arranged into what?

Columns

e.g columns for each finger 

6

What happens to the columns of somatosensory cortex corresponding to an area of the body if that area of the body is amputated?

They process info from the adjacent areas of the body instead

i.e other sensory areas take over

7

What happens to the contralateral somatosensory cortex if a part of the body receives more sensory input?

It enlarges

8

Sensory info from one side of the body is processed on the (ipsilateral / contralateral) side of the brain.

contralateral

9

Which somatosensory cortex integrates sensory, visual and auditory information?

S2

just posterior to S1

10

Where is the S2 somatosensory cortex?

What is its function?

Posterior parietal cortex

Integrates information from S1 so you know what an object is without having to analyse it

11

What are the two main sensory pathways we need to know about?

Dorsal column / medial lemniscus pathway

Spinothalamic tract

12

Where do sensory nerve fibres decussate (cross over) in the DC/ML pathway?

Pyramids of the medulla

13

Where do sensory nerve fibres decussate in the spinothalamic tract?

Immediately at the spinal cord level they entered at

14

What structures are connected by the

a) 1st

b) 2nd

c) 3rd order neurons of the DC/ML pathway?

a) Spinal cord to medulla

b) Medulla to thalamus

c) Thalamus to post-central gyrus

15

What structures are connected by the

a) 1st

b) 2nd

c) 3rd-order neurons of the spinothalamic tract?

a) Sensory neuron to spinal cord

b) Spinal cord to thalamus

c) Thalamus to post-central gyrus

16

What is the medial tract of the DC/ML pathway called?

Fasciculus gracilis

17

What is the lateral tract of the DC/ML pathway called?

Fasciculus cuneatus

18

The fasciculus cuneatus runs in the ___ aspect of the dorsal column.

The fasciculus gracilis runs in the ___ aspect of the dorsal column.

fasciculus cuneatus lateral dorsal column

fasciculus gracilis - medial dorsal column

19

Sensory fibres from which parts of the body run in the fasciculus cuneatus?

Upper trunk

Arms

20

Sensory fibres from which parts of the body run in the fasciculus gracilis?

Lower trunk

Legs

21

Sensory information from which spinal levels is carried in the fasciculus gracilis?

T6 and below

22

Sensory information from which spinal levels is carried in the fasciulus cuneatus?

T5 and above

23

The DC/ML pathway is the main route by which sensory fibres reach the brain.

Which cranial nerve is the exception and which part of the body does it supply?

CN V

Anterior head

24

Where do fibres synapse at the end of the

a) fasciculus cuneatus

b) fasciculus gracilis?

a) Cuneate nucleus

b) Gracile nucleus

25

Where do fibres from the DC/ML pathway decussate?

Medulla

26

Sensory information regarding fine touch, proprioception and vibration from the right side of the body is processed on the left side of the brain.

Why?

100% ​decussation at medulla

27

After decussating at the medulla, how do DC/ML fibres reach the thalamus?

Medial lemniscus

hence the name

28

How do sensory fibres from the DC/ML pathway travel from the thalamus to the primary somatosensory area?

Internal capsule

29

Which senses are provided by the DC/ML pathway?

Fine touch

Vibration

Proprioception

30

What is stereognosis?

Ability to recognise an object using fine touch