Masticatory feedback: proprioception Flashcards
Kinaesthesia
movement awareness (swimming, dancing, running)
Muscle spindles
prioprioceptors in the body of the muscle
Golgi tendon organs
proprioceptors within the tendons
Fibre types in muscles (2)
- Extrafusal:
– Bulk of the muscle fibres – Contractile - Intrafusal
– Muscle spindles
– Specialised muscle fibres – Within a ct capsule
Anatomy of extrafusal fibres
Stripy parts represents contraction
Innervation of extramural fibres
Innervation of extramural fibres
Intrafusal fibres
Relationship between spindle activity and muscle stretch
Spindle activity increases with greater stretch
Masticatory muscle spindle cell bodies in…
trigeminal mesencephalic nucleus
Muscle spindle afferents synapse in…
§ V motor nucleus and….
§ Other areas linked to sensorimotor regulation:
– Cerebellum
– Cerebral Cortex
When muscle contracts in the jaw muscle…
As well as the alphas being active, the gamma is swell to keep the spindle in tension, allowing proprioceptive feedback. Without this we would loose perception of where the jaw is.
Joint receptor types
§ Pacinian – in ligaments - acceleration
§ Golgi – in ligament - position
§ Ruffini - in capsule- movement
Golgi tendon organs
§ In tendons, in series with muscle fibres
§ Very few, if any, in masticatory muscles
§ Tension receptors
§ Role in (inhibitory) reflex -prevention of XS stretch of muscle
