Proprioception Flashcards
1
Q
What is proprioception? - kinaesthesia?
List some proprioceptors:
A
Proprioception: awareness of position of body parts in relation to each other and surroundings
- kinaesthesia - movement awareness
Proprioceptors:
- muscle spindles: present within body of muscle (muscles of mast, maybe lateral pterygoid)
- golgi tendon organs: within tendons, force receptors - not present in masticatory system, replaced by PDLM acting as force tranducers
- joint receptors: in the capsule of TMJ, tendons and ligaments of the joint
- generally no tendons in the masticatory system, only between ABD and PBD
2
Q
What are the fibres in muscles?
A
Extrafusal: bulk of muscle fibres
- contractile
- supplied by alpha motor neurones
Intrafusal: receptors in the muscles (muscle spindles)
- specialised muscle fibres within a capsule
- in parallel to extrafusal fibres
3
Q
What innervates intrafusal fibres?
A
Afferents (from periphery to CNS): activated by stretch
Primary annulo-spiral nerve ending: detects length of fibres and speed of change of length
Secondary nerve endings: detects length of fibres on contractile portion
Efferent: gamma motor neurones - supply contractile ends
4
Q
What is the role of the muscle spindle?
A
- information about muscle length - the more stretched, the more APs that are fired
- acts to maintain muscle length
- load compensation
5
Q
What are gamma motor neurones?
A
- cause contraction of intrafusal fibres
- maintain tension in spindle
- maintain spindle afferent activity
- alpha-gamma co-activation
