The Neuromuscular Basis Flashcards
What is the order in which a nerve impulse travels down a neuron?
dendrite cell body (nucleus) Axon Myelin Sheath Syanpse
What is another word for nerve impulse?
action potential
What is the word for a signal that passes from one neuron to the next and finally the muscle fibers?
action potential
What voltage is considered resting potential for a neuron?
-70 mV
When is the membrane considered polarized?
whenever there is more sodium outside and more potassium inside
Explain the process of depolarization?
Resting Membrane Potential moves to 0 mV; channels open and allow Sodium in and potassium out
What is the threshold required in order for depolarization to occur?
-55mV`
Explain Re polarization
channels open to where sodium moves out and potassium moves in
What is a neuromuscular junction?
the nerve terminal where there is a space between the neuron and the end plate of the muscle
What happens at a neuromuscular junction?
ACH is released and it binds to the receptor on the end plate of the muscle, then ACH turns into Ca
What type of neuron sends sensory information to the CNS?
Afferent
What type of neuron sends motor information to the PNS?
Efferent; the “effect” is caused, this is information for muscular contraction
What is a bundle of afferent and efferent neurons called?
Sciatic Nerve
On a graph what type of neuron is ascending and descending?
Ascending=Afferent
Descending=Efferent
What are the types of interneurons?
Aff-Eff
Eff-Eff
High part of the brain
What do nodes of ramvier do on a motor neuron?
speed up the AP; the gaps between the fatty substances
What produces mylenation?
Schwann cell; are the fatty substances on the myelin sheath
What is a motor unit?
motor neuron and all of the muscle fibers it innervates (distributes)
What is the smallest unit of muscles shortening?
motor unit
What does precision do for a motor unit?
the number of motor neurons determines how precise the movements are in that muscle
How many motor neurons are present in a muscle?
100-200
The smaller number of motor units the more precise the movement is
shah
What is the all or non principle?
whenever all fibers of a motor unit produce tension together
What are the different types of motor units?
I, IIa, IIb
What is process that increases the number of stimulated motor units?
recruitment
What is the process that increases the stimulation rate of the active motor units?
rate coding
Which type of muscle fiber has a slow contraction, generates little tension, and maintains posture?
Type I
Which muscle fiber has fast contractions, more fatigue resistant?
Type IIa
swimming, biking
Which type of muscle fiber produces rapid contraction, distributed by alpha neurons, have a wider diameter?
type IIb; weightlifting
During rate coding, what produces the effect of a single stimulus?
twitch
During rate coding, what produces the overall effect of added stimuli?
summation
During rate coding, what produces max tension due to high frequency stimulation?
tetanus
What type of twitch relaxes and stimulates faster?
Fast twitch
What type of twitch takes longer to stim and relax?
Slow twtich
During recruitment, what is the order of the size principle?
Type I, then IIa, then IIb
What is asynchronous activation?
whenever activation is spaced with preceding motor unit activity
What is synchronous activation?
large and small motor units activated together
During recruitment what can high frequency coding do?
induces high tension production aka rate coding
For small muscles, what percent of units need to be activated for voluntary contractions?
30-50%
For large muscles , what percent of motor units need to be activated for voluntary contraction?
100%
What are the main sensory receptors for muscles?
proprioreceptors
What monitors muscle strength?
muscle spindles
What do muscle spindels respond to?
muscle length and velocity
What is autogenic facilitation?
The process of inhibiting the muscle that generated a stimulus while providing an excitatory impulse to the antagonist muscle
What is reciprocal inhibition?
process of muscles on one side of a joint relaxing to accommodate contraction on the other side of that joint
What do muscle spindles cause?
autogenic facilitation
reciprocal inhibition
What type of fibers are innervates muscle spindles?
intrafusal fibers
What are intrafusal fibers with large nuclei in them?
nuclear bag fibers
What innervates the contractile ends of a motor spindle?
gamma motor neuron
What readjusts the muscle spindle length by contracting intrafusal fiber?
gamma bias
What type of chain is it whenever the intrafusal fibers are arranged with nuclei in rows?
nuclear chain fiber
What does stretch reflex do?
orders contraction of a muscle being stretched
What does the Golgi Tendon Organ do?
monitors muscle tension
What are fibers outside of the muscle spindle?
Extrafusal spindle
Where is the GTO located?
myotendinous junction, attached to muscle fibers so more sensitive to contraction then stretch
What does ballistic stretching target?
muscle spindles, which causes relaxation
What does static stretching target?
minimizes muscle spindle response, but targets the GTO response
what responds to a change in joint position and velocity?
ruffini ending
What responds to pressure and pain?
pacinian corpuscle
What happens to neurons during strength training?
they adapt and are able to withstand more load
Bilateral Deficit
loss of both force through bilateral training
what is the purpose of pylometric training?
improve velocity of performance
