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KMCI Muscle

Terms in this set (23)

muscle mass depends on
balance of protein synthesis and degredation
Why is muscle necessary
Because gravity is constantly acting on the body and muscle is the force necessary to oppose it and maintain posture
4 requirements for human motion
stimulus generator (CNS)
Stimulus carrier (nerve)
muscle
joint
Motor unit consists of
a single motor neuron (plus its axon) and the multiple muscle fibers it controls.
Each muscle fiber is innervated by how many motor neurons?
1
In the sliding filament theory of muscular contraction, when the actin is pulled inward on the myosin what shrinks
H zone and I band
A single muscle fiber will have which type of myosin heavy chain
May simultaneously express more than one type (Type 1 & Type IIA)
The two main types of muscle fibers are classified based on...
how ATP is produced
type of motor neuron innervation
type of myosin heavy chain expressed
3 types of muscle fibers
Type 1: slow oxidative - fatigue resistant
Type 11A: FOG - intermediate - walking
Type 11X: FG - fatigable - jumping
4 Characteristics of Type I fibers
.
Large and numerous mitochondria
Low myosin ATPase activity
Slow Ca handling ability and shortening speed
Less well developed glycolytic capacity than fast-twitch fibers
4 characteristics of Type II fibers
high capability for electrochemical transmission of Action Potentials
High myosin ATPase activity
Rapid Ca2+ release and uptake by an efficient sarcoplasmic reticulum
High rate of cross-bridge turnover
how many recognized muscle fiber types are there ?
7
4 characteristics of skeletal muscle
excitability
elasticity
extensibility
contractility
how much work is being done in an isometric contraction
none
eccentric vs concentric: motion goes in direction of
Eccentric: motion goes in direction of the load
Concentric: motion goes in direction of the muscle
6 factors that affect muscle force production
motor unit recruitment
preloading
muscle size
velocity of shortening
muscle fiber arrangement
length-tension relationship
2 ways force production is controlled in motor unit recruitment
frequency of stimulation of motor units
number of motor units activated
why does max force not occur instantaneously?
because in preloading the release of calcium and binding of myosin does not occur instantaneously
explain the relationship between force production and velocity of CONCENTRIC muscle contractions
they are inversely related
faster movement: less force production
slower movement: more force production
relationship between force production and velocity of ECCENTRIC muscle contractions
as velocity increases so does force production
if a pennate muscle of 30 degrees contracts how much muscle force will it produce
only 86% of its force through the tendon
4 beneficial changes that occur when you endurance train your muscles
improves O2 transport and efficiency of delivery chain
Capillary supply increases; number and size of mitochondria
Fat and glycogen stores and oxidative enzymes enhanced
More development of sarcoplasmic reticulum
what are the three fundamental adaptations necessary for muscle hypertrophy
increased protein synthesis
addition of myofilaments, myofibrils, and sarcomeres
satellite cell activation and fusion
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