Sensory function Flashcards
what is a muscle spindle
contained in its own fascia, has actin/myosin at the ends, only cell bodies in the middle and no connective tissue, mediates tendon relfexes, proprioceptive responder
what type of afferent nerves go away from muscle spindles
1a afferetns
what do gamma motor neurones do
maintain the stretch of middle of 1a afferents so proprioceptive signal can keep going to the brain
what happens when you tap the patellar tendon
volley of action potentials
what motor neurones innervate extrafusal muscle fibres
alpha
what are extra/intra fusal motor neurones
extrafusal - normal
intra - inside muscle spindles
are gamma motor neurones innervated by reflexes (normally)
no
what happens when ++ gamma innervation
hyperreflexia
which tract innervates gamma motor neurones
CST
where are golgi tendon organs
in tendons, interweaved with collagen
what information do golgi tendon organs relay
how much tension in the tendons
what is the inhibitory neurotransmitter provoked by ++ golgi activation
glyceine
what afferents go away from golgi TOs
1b
what lamina do lower motor neurones arrive at
XI
how many action potentials/s needed for tetanus
> 10/s
what happens is motor action potentials <10/s
jerky twitchy
what happens if bits of motor neurones die & what’s the downside
neighbouring ones fill in te gap, but loss of fine motor control
which reflexes are monosynaptic
ankle, biceps, triceps, patellar, supinator
what is a homonymous reflex
same muscle eff and afferent
what is temporal summation
many action potentilas in a short time go over threshold
what is spatial summation
several inputs from different axons add up to go over threshold
which sort of receptor reacts in flexion withdrawal reflex ( eg step on a pin)
A delta
why can flexion withdrawal reflex be overridden
interneurones
what do MS and diabetic neuropathy have in common
falls
symptoms of U motor neurone pathology
spasticity, rigid paralysis
symptoms of lower motor neurone pathology
flaccid paralysis
