Mechanoreception

Question 1

What does peripheral receptor equal?

Answer 1

mechanoreceptor

Question 2

In terms of mechanoreception what does adequate stimulus equate to?

Answer 2

Mechanical distortion
- pressure
- vibration
- tension

Question 3

What is exteroception?

Answer 3

• Give information about things coming into contact with the body

Question 4

What is proprioception?

Answer 4

• Proprio (latin - “about self”)
• awareness of position

Question 5

What is touch?

Answer 5

The sensory experience when mechanoreceptors are excited - involves central nervous system

Question 6

What are examples of oro-facial mechanoreceptors?

Answer 6

Mucosa (and skin)
- food texture etc
- important for mastication
Periodontal ligament
- forces on teeth
Muscles
- muscle spindles - muscle length
Joint receptors
- joint position and movement

Question 7

What is the effect of stimulation of mechanoreceptors?

Answer 7

• sensation of touch
• reflexes e.g.
  jaw muscle reflexes
  salivary reflexes - chewing gum
• Interact/modulate other sensory modalities:
• the effect of rubbing a painful area - gate control

Question 8

What is the receptive field?

Answer 8

the area/space where a stimulus will affect the receptor

Question 9

What does 2 point discrimination reflect?

Answer 9

• innervation density
• size of receptive field

Question 10

describe PDL

Answer 10

important “sensory” organ
- exteroceptive role
and
- proprioceptive role

Question 11

PDLM properties

Answer 11

• no branched axons between adjacent teeth PDLs - easy to localise
• Innervation density higher at apex
  adequate stimulus:
• tension in the PDL due to pressure applied to tooth
• tooth moves around a fulcrum

Question 12

amount of PDLM activity depends on?

Answer 12

• direction of applied force
• magnitude of force
• adaptation properties
• threshold of the receptors
• position of receptors in PDL

Question 13

Same receptor, why differences in properties?

Answer 13

• linked to position relative to fulcrum
• smaller stimulus nearer the fulcrum

Question 14

describe sensory pathway

Answer 14

stage 1: mechanoreception
- transduction of stimulus
- propagation along primary afferent nerve
stage 2: processing at first synapse
- trigeminal nucleus
stage 3: processing in thalamus
stage 4: conscious perception
- somatosensory cortex

Question 15

describe trigeminal pathways

Answer 15

Primary afferent cell bodies:
- V ganglion
- mesencephalic nucleus (PDL)
Synapse:
- mainly in main sensory nucleus
- project to spinal V nuclei as well
Project to: sensory cortex via thalamus

Question 16

Answer 16

Question 17

Answer 17

Question 18

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Question 19

Answer 19

Question 20