Masticatory feedback: Mechanoreception Flashcards
Mechanoreception: stimuli
Detection of mechanical stimuli
Peripheral receptor = mechanoreceptor
Adequate stimulus: mechanical distortion
– Pressure
– Vibration
– Tension
Exteroception
- Give information about things coming into contact with the body
Proprioception
- Proprio- (Latin=“About self”)
- Awareness of position
Touch
- The sensory experience when mechanoreceptors are excited - involves central nervous system
What is the effect of stimulation of mechanoreceptors?
§ 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
How can mechanoreceptors be classified?
- Physiological classification (adaptation properties, receptive field size)
- Anatomical classification
Rapidly adapting mechanoreceptors
Slowly adapting mechanoreceptors
Periodontal Ligament Mechanoreceptors (PDLMs) role
Exteroceptive and Proprioceptive role
Periodontal Ligament Mechanoreceptors (PDLMs): Nerve endings
Ruffini
Periodontal Ligament Mechanoreceptors (PDLMs): afferents
– A-beta axons
– ~300 per tooth
Periodontal Ligament Mechanoreceptors (PDLMs): Cell bodies
– V ganglion
– mesencephalic nucleus
How study PDLM properties?
§ Animal studies (e.g. Linden RWA et al) – Cat canine preparation
– Localise individual receptors – Single fibre recordings
§ Human studies (e.g. Trulsson M et al) – Recordings from inferior alveolar nerve – Discrete forces applied to teeth
Activity vs force: buccally, distally, mesially, lingually.
Sensory pathway: stage 1
Mechanoreception
– Transduction of stimulus
– Propagation along primary afferent nerve
How is touch sensation ‘sharpened’ by the brain
- Skin is distorted
- Nerve ending closes will be strongest from the centre, and weaker from the surrounding areas
- The presynaptic inhibition will mean that the surrounding nerves are inhibited.
- This effect “sharpens” the sense and
