neuromuscular system Flashcards
what are 3 basic types of nerurons
motor neurons, interneurons, sensory neurons
Wher does cell body reside?
in spinal chord
What tupeof nerves do axons form?
perupheral nerves
what is a motor unit
a motor neuron and all the msucle fibres it innervates
What ate th three motor unit + muscle fivre types?
slwoly contractin - I (slow twitch)
fast contractin, fatigue resistant (IIa - fast twitch)
Fast contacting, fast fatigu (FF) - IIx IIb (fast-twitch)
what is hennemans size principle?
Excittor input require to reah threshold increases with soma size so motro neurons (MUS are ecruited in a orderly fahiion from small to large
Neurons and skel muscle cells have a ____ membrane witha. ____ charge on inside
Resting membran potential (RMP) is generall between ____
Neurons and skel muscle cells have a __polarized__ membrane witha. ___neg_ charge on inside
Resting membran potential (RMP) is generall between -65 and -70
if sum of inputs causes the RMP to change wga twill result?
if RMP changes to approx -55mV an action potential wukk occur
What is an action potential?
transient reversal in the potential differnce across membran that is trasnmitted rapidly across exciteable membrane
How does nerve impulse go to muscle contraction
if another AP arrives before msucle relaxes it will icnrease beyond a single twitch - twtitch summation
what are the 2 mechanisms tha tmotro neuron pools control force production
the nbumber of active motor units (recruitment)
the discharge rate of active motor untis (rate coding)
What is the distinguisihing feature of the msucualr system?
shorten and produce tension
Skeletal muscle functions
movemet and posture control
Heat production (75% of chem energy used in contraction)
Protenction of organs
muscle pump to return blood to heart
A muscles line of pullr efers to what?
direction of resultant force produced at an attachment
How do FIbres oriented at an angle impact force per fiver and whole mucle force?
Force per fibre is less in the direction of pul and whoel muscle force is greater becuase there are more fibres
