Process of Somatosensory input

Question 1

What does the somatosensory system do?

Answer 1

Mediates all sensation that are not visual, auditory, gustatory, olfactory or vestibular

Question 2

What are exteroceptive sensations?

Answer 2

Sensation from the surface of the body

Question 3

What are proprioceptive sensations?

Answer 3

Sensation from sensors in muscles, tendons and joints concerning posture and movement

Question 4

What are visceral sensations?

Answer 4

Sensation from internal organs

Question 5

What is modality?

Answer 5

Type of stimulus transduced into an electrical signal (i.e. pain, itch etc.)

Question 6

What are deep sensations?

Answer 6

From fasciae, muscles and bone

Question 7

What are low threshold units?

Answer 7

Respond to low intensity stimuli

Question 8

What are high threshold units?

Answer 8

Respond to high intensity stimuli

Question 9

What is a type of high threshold unit?

Answer 9

Nociceptor

Question 10

What sort of stimuli induce a response from low threshold mechanoreceptors (LTM)?

Answer 10

Touch, vibration, pressure

Question 11

What is adaption?

Answer 11

The ability of a receptor to display a rate of change in the firing of action potentials under stimuli

Question 12

What is conduction velocity?

Answer 12

The speed at which a neuron is able to conduct

Question 13

How does myelination effect conduction velocity?

Answer 13

The thicker the myelination, the faster the neuron can conduct

Question 14

What is receptive field?

Answer 14

The region that when stimulated causes a response in a specific neuron

Question 15

What do free nerve endings do?

Answer 15

Responsible for sensation of pain and temprature

Question 16

What do Meissners corpuscles do?

Answer 16

Respond to stroking and flutter

Question 17

What do Merkel’s discs do?

Answer 17

Detect pressure and texture

Question 18

Where are meissner’s corpuscles found?

Answer 18

Often at areas where two-point discrimination is found. Very superficial

Question 19

What do Ruffini endings do?

Answer 19

Respond to stretching of skin - (constant stimuli)

Question 20

What do Pacinian corpuscles do?

Answer 20

Respond to vibrating stimuli - (rapidly changing stimuli)

Question 21

Where are merkel cells found?

Answer 21

Superficially

Question 22

Where are Pacinian corpuscles found?

Answer 22

Deep

Question 23

Where are Ruffini endings found?

Answer 23

Deep

Question 24

What are laminae of the spinal cord?

Answer 24

10 layers of grey matter within the spinal cord

Question 25

What laminae do nociceptors terminate in?

Answer 25

1&2

Question 26

What laminae do low threshold mechanoreceptors terminate in?

Answer 26

3-6

Question 27

What laminae do proprioceptors terminate in?

Answer 27

7-9

Question 28

What class of fibres transmit mechanical information

Answer 28

Ab

Question 29

What class of fibres transmit proprioceptive information

Answer 29

Aa

Question 30

What class of fibres transmit nociceptive information

Answer 30

Ac

Question 31

Where do the proprioceptive and mechanical sensation pathways decussate?

Answer 31

Medulla

Question 32

Where do the pain sensation pathways decussate?

Answer 32

spinal cord

Question 33

Damage to one side of the spinal cord would result in loss of proprioceptive and mechanical sensation on what side?

Answer 33

The ipsilateral side

Question 34

Damage to one side of the spinal cord would result in loss of pain sensation on what side?

Answer 34

The contralateral side