Somatosensory

Question 1

Types of afferent fibres and the modality?

Answer 1

Aalpha - proprioception
Abeta - pressure/vibration
Adelta- thermal sensation/nociception
Cfibres - nociception and itch

Question 2

How is stimulus intensity detected?

Answer 2

Graded response can be produced

Question 3

Variance in receptive fields can by tested through

Answer 3

2-point descrimination

Question 4

Muscle spindles lie

Answer 4

In parallel with fibres

Question 5

GTOs lie

Answer 5

In series with fibres

Question 6

A alpha fibres synapse in which laminae

Answer 6

VI, VII and IX

Question 7

A beta fibres synapse in which laminae?

Answer 7

III, IV, V (nucleus proprius)

Question 8

Spinocerebellar afferents synapse in

Answer 8

VII, Clarke’s column and project to inferior cerebellar peduncle

Question 9

Clarkes column is associated with which ascending path?

Answer 9

Spinocerebellar

Question 10

Substantia gelatinosa is associated with which modality and ascending path?

Answer 10

Pain, anterolateral spinothalamic tract C fibres

Question 11

Nucleus proprius is associated with which, fibres and modality?

Answer 11

A delta carrying pain

A beta carrying general sensation

Question 12

Lamina 1 received input from

Answer 12

Lissauer’s tract (pain and temp)

Question 13

Dorsal column sends information to

Answer 13

VP thalamus and S1

Question 14

Proprioception S1

Answer 14

3a

Question 15

Touch S1

Answer 15

3b

Question 16

Rapidly adapting fibres

Answer 16

Stop firing action potentials as soon as the produced skin indentation is stationary

Question 17

Slowly adapting fibres

Answer 17

Respond to steady skin indentation with sustained discharge of action potentials.

Question 18

Which touch fibres (1 or 2 ) are superficial and deep?

Answer 18

1 superficial

2 deep

Question 19

SA1, SA2, RA1, RA2 types

Answer 19

Merkel’s discs
Ruffini
Meissner’s
Pacinian

Question 20

Type 1 sensory receptors better at

Answer 20

Small details

Question 21

Type 2 better at

Answer 21

Pressure and vibration

Question 22

Sensitive to edges and corners

Answer 22

Merkel’s discs

Question 23

Meissner’s structure

Answer 23

Encapsulated unmyelinated nerve endings, surrounded by Schwann cells.

Question 24

Good for microdetection of detailed surface features

Answer 24

Meissener’s (rapid adapting good for high acuity)

Question 25

Ruffini corpuscles located?

Answer 25

Palmar folds and finger joints

Question 26

Pacinian corpuscles structure

Answer 26

Wrapped in successive layers of connective tissue and myelin called lamellae separated by fluid-filled space.

Question 27

Ruffini sensitive to

Answer 27

Skin stretch, stereognosis

Question 28

Good for pressure and vibration

Answer 28

Pacinian corpuscles

Question 29

TRPV1

Answer 29

Hot painful capsaicin receptor

Question 30

TRPV2

Answer 30

Hot, not responding to chemicals (very hot >52 degrees)

Question 31

TRPV8

Answer 31

Extreme cold receptor

Question 32

A alpha fibres synapse on

Answer 32

Motor neurons, motor Ia inhibitory interneurons and sensory (lamina 6) interneurons

Question 33

A beta proprioception primarily from

Answer 33

Static bag and chain fibres

Question 34

A alpha proprioception primarily from

Answer 34

Both dynamic and static information

Question 35

Touch receptors afferent neuron

Answer 35

A beta (and static proprioception)

Question 36

Thermosensitive a delta project to

Answer 36

Nucleus proprius

Question 37

A delta pain synapses in

Answer 37

Laminae I

Question 38

C fibre pain synapses in

Answer 38

Laminae II interneurons

Question 39

Adelta touch is?

Answer 39

Crude touch

Question 40

Sensory afferents go to ipsilateral/contralateral thalamus

Answer 40

Contralateral

Question 41

Spinal level above which cuneate tract

Answer 41

T6 up

Question 42

Spinal level below which gracile tract

Answer 42

T7 down

Question 43

Gracile is medial/lateral to cuneate

Answer 43

Medial

Question 44

Sensory decussation occurs

Answer 44

Lower medulla (medial lemniscus forms)

Question 45

In medial lemniscus are lower limb medial or lateral

Answer 45

Lateral

Question 46

Mesencephalic nucleus of trigeminal

Answer 46

Midbrain, proprioception | A alpha

Question 47

Principle nucleus of trigeminal

Answer 47

Pons, touch, A beta

Question 48

Spinal nucleus of trigeminal

Answer 48

Medulla, pain/temp, a delta

Question 49

Where does principle trigeminal nucleus axons go?

Answer 49

Cross to join medial lemniscus and terminating in VPm

Question 50

Where do mesencephalic trigeminal nucleus axons go?

Answer 50

Motor nucleus V

Question 51

Where does spinal trigeminal nucleus axons go?

Answer 51

Anterolateral tract

Question 52

Area 1

Answer 52

Receives large amounts of input from RA1/2 and is thus important in integrating texture

Question 53

Area 2

Answer 53

Receives inputs from 3a in addition to 3b and therefore is key in combining proprioception with touch information, this underpins stereognosis

Question 54

S2

Answer 54

Tactile memory

Question 55

Areas 5&7 posterior parietal

Answer 55

Tactile memory and sensory integration

Question 56

Brown sequard

Answer 56

Loss of ipsilateral sensation and proprioception Contralateral loss of pain and temperature LMN lesion at the level of the lesion UMN lesion below level of the lesion ANS loss

Question 57

Central cord syndrome

Answer 57

Medial corticospinal tract (upper limb/axial muscles) UMN lesion Progressive loss of sensations

Question 58

Anterior cord syndrome

Answer 58

Preserve proprioception and touch Crossing anterolateral pain fibres - loss of pain and temperature sensation Loss of corticospinal fibres

Question 59

White matter, the higher the vertebrae?

Answer 59

White matter increases as more fibres

Question 60

Until T6 there is only one...

Answer 60

Dorsal column (gracilis)

Question 61

Intermediate horn is much larger where?

Answer 61

``` Thoracic spine (T1-T12) lots of visceral output ``` and Clarke's column

Question 62

Larger ventral horns where?

Answer 62

(L2-S2), shows where there are large amounts of motor neurons for innervation of the lower limb. Upper limb is in the cervical segments C4-T2