Somatosensory and Proprioception

Question 1

What is meant by the terms

1) proprioception
2) kinaesthesia

Answer 1

1 = detection of a limb in space
2 = detection of movement

Question 2

What are the somato-senses?

Answer 2

Touch
Pain
Temperature
Proprioception
Kinaesthesia

Question 3

Which pathways do not decussate?

Answer 3

Kinaesthesia and proprioception

Question 4

Where does pain decussate?

Answer 4

Around the spinal cord segment

Question 5

What is a nociceptor?

Answer 5

Neuron that detects pain

Question 6

What is the name of the touch/sensory receptors in the skin?

Answer 6

Pacinian corpuscles

Question 7

What are the 5 types of sensory receptor?

Answer 7

• Meissner
• Merkel disc
• Pacinian
• Ruffini
• Free nerve ending

Question 8

How do slowly adapting primary afferents fire action potentials?

Answer 8

When a force is applied to a receptor the response is slower and then action potentials continually fire

Question 9

Where are large receptive fields found?

Answer 9

Hairy skin

Viscera

Question 10

What is a mechanoreceptor and what is its function?

Answer 10

Ion channel that sits in the neuronal membrane and when it detects a chemical, temperature or movement it registers a depolarisation and fires

Question 11

Which types of nerve fibres is the fastest?

Answer 11

Aa fibres = 72-120m/s

Question 12

Which type of nerve fibres is the slowest?

Answer 12

C-fibres = 0.4-2m/s

Question 13

Where do pain and temperature pathways cross over?

Answer 13

in spinal cord

Question 14

Where do touch and proprioception pathways cross over?

Answer 14

Medulla

Question 15

What is the medial lemniscus?

Answer 15

A collection of nerve pathways that runs through the midbrain

Question 16

Which pathway is most involved with pain?

Answer 16

Ventrolateral pathway

Question 17

What does the ventrolateral pathway include?

Answer 17

Spinothalamic tract & spinoreticular tract

Question 18

Where does the spinocervical tract cross over and travel through?

Answer 18

Crosses just below the midbrain and travels through the medial lemniscus

Question 19

Where does a somatosensory reflex have to travel through before we are consciously aware of it?

Answer 19

The thalamus

Question 20

Where is gait generated?

Answer 20

In the spinal cord - each limb has a central pattern generator

Question 21

How is speed calculated?

Answer 21

stride frequency x stride length

Question 22

What is the role of proprioceptors?

Answer 22

Proprioceptors inform CNS of body position, strength and speed of movement, so motor output can be modified as needed.

Question 23

When can an animal demonstrate normal proprioception?

Answer 23

If they have normal motor function

Question 24

What is the difference between conscious and sub-conscious proprioception?

Answer 24

Conscious – fine detailed movement

Subconscious – larger movements e.g. position of arms and legs

Question 25

Does conscious or sub-conscious proprioception decussate?

Answer 25

Conscious

Question 26

What deficits are shown by damage to conscious proprioception?

Answer 26

Stumbling, knuckling, intention tremor

Question 27

What deficits are shown by damage to sub-conscious proprioception?

Answer 27

Ataxia = Alteration in the rate, range and force of movements

• swaying of the body
• wide/narrow stance
• non-intention tremor

Question 28

Where are conscious and subconscious tracts located?

Answer 28

Conscious = dorsal funiculus 
Subconscious = lateral funiculus

Question 29

Which type of proprioception is the cerebellum involves with?

Answer 29

Sunconscious

Question 30

What is mentation?

Answer 30

Behaviour, reactions, etc