Week 3A Flashcards
(TRUE OR FALSE) The soleus will have lower motor unit
firing rates (less rate coding) than the biceps brachii. Why?
TRUE - becuase soleus has large range of recruitment - small range of firing rate
wheras biceps brachi uses less recuitment and more firing rate
(TRUE OR FALSE) To maintain a steady/ smooth contraction
at 8Hz, each motor unit produces a partially fused tetanus
by firing synchronously.
FALSE. - each motoru init fires asycnchronysly to produce smooth tetanus
(TRUE OR FALSE) During a fast contraction, the motor
neuron action potential threshold will be lower, or decrease
compared to a slower contraction.
false the threshold for wich ap is fired stays the same stays the same - recuitment theroshold just changes - amount of force needed to get MU firing AP
does action potential threshold change?
No action potential threosshold does not change but recruitemnt throshold does
what is the function of a muscle spinde;?
A muscle spindle dtects velocity(rate of length change) and length of the stretch of a muscle
msucle receptors that rpovide feedback to CNS about muscle length (stretch) + rat of length change
what is alpha gamma coactivation?
During avoluntary both the alpha and gamma system are activated (alpha MN and gamma MN) which activate both msucle spindles and the muscle so that the spindle maintains sensivity during shortening
why does tendon tap cause a reflexive kick
it stretches the muscle and spindle and typ Ia afferents sensitive to strectch activate MN via the monosynaptic reflex
why are gamma motor neurons so important
Because they prevent the muscle spindles from becoming unloaded and keeps it sensitive to stretch
whre are GTOS located?
in the tendon junction
spindles like _____ to teh muscle while GOS lie _____
spindles - parallel
GTO’s line in series with muscle fibres
the affernt fibre tha innervated the golgi tnedon organ is the _____ afferent
Ib
what is the role od GTO receptors?
provide feedback to the CNS about muscle force /tension
primarily ACTIVE force/tension
GTOs are bundles within a capsule containing ___ an d____
these things are ____ with one another
nerve endings nad collagaen fibres
interdigitate with each other (intertwined)
what is the role of muscle spindles vs GTO
msucle spindles sense muscle length and velocity (both static and dynamic) whereas GTO receptors detect ACTIVE muscle force and tension
what technique alows experimenter to record action potetnitals from sensory afferents in awake human?
microneurography
level of force eneeed to excite a GTO depedns
on mode of activation
passive stretch of GTO requires ____ newtons whereas active ovnraciron (eg activation of single muscle iber) can actiate GTO at ___
2, 30-90millinewtonss
Golgi tendons are more sensitive to ___ forces __ than __ stretch
active, passive
A ___ is the force output of. amusclein response to one stimulus
twitch
golgi tendon organs respind to increaed ___ during a twitch
muscle tension
what is the main thing that the GTO does and what are the 2 main fucntion
ingibit the agonist muscle
which is a proctive mechanism and monitors and mdoualtes force control
GTOS provide motor feedback to ____ via the ____ and ___ the inhibiitory____
motro feedabck to spincal chord via Ib afferent and Ib inhibitory interneuron
GTOS have. ______synaptic connection to motor neuron
DI
what is autogenic inhibition
trggered by activation of golfit tendon organs - reflex wher emsucle relaxes involunatiry when it expriences excessie tension
GTOs are aer sentitive to __ and activeae when___
muscle tension and acivated when muscle tension incrased
Reflexive inhibiton of motor neuron activity - used as a ___ mechanism
protective
how are golgi tendon organ relevant in low force tasks
Help w fine tuning of muscle activity - mroe rpecise and control mvoements - basically modualting force control for low force tasks
how does GTO act as a protective mechanism?
he GTOs are part of the body’s feedback system that protects against excessive force. When tension in the tendon becomes too high, the GTOs send signals to the spinal cord to inhibit the motor neurons, which reduces the muscle’s contraction strength
