Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
52 Cards in this Set
- Front
- Back
|
Human body contains over |
600 skeletal muscles (40-50% of total body weight) |
|
|
3 major functions of Skeletal Muscles |
Force production for locomotion and breathing, and for postural support, also heat production during cold stress. |
|
|
Flexors |
Decrease joint angle |
|
|
Extensor |
Increase joint angles |
|
|
Epimysium |
Surrounds entire muscle |
|
|
Perimysium |
Surrounds bundles of muscle fibers |
|
|
Endomysium |
Surrounds individual muscle fibers |
|
|
Satellite cells |
Play key role in muscle growth and repair |
|
|
Myonuclear domain |
Volume of cytoplasm surrounding each nucleus |
|
|
More nuclei allows |
Greater protein synthesis |
|
|
Myofibrils |
Contain contractile proteins such as actin (thin) and Mayosin (thick) |
|
|
Sarcoplasm reticulum |
Storage sites for calcium, terminal cisternae |
|
|
Sarcomere |
Includes z line, M line, h zone, A band, I band |
|
|
Transverse tubules |
Extend from sarcolema to sarcoplasmatic recticulum |
|
|
Neuromuscular Junction |
Junction between motor neuron and muscle fiber |
|
|
Motor end plate |
Pocket formed around motor neuron by sarcolemma |
|
|
Neuromuscular cleft |
Short gap between neuron and muscle fiber |
|
|
Individual muscle fibers are composed of hundreds of threadlike protein filaments called |
Myofibrils |
|
|
Importance of myonuclear domain |
single nucleus is responsible for the gene expression for its surrounding cytoplasm |
|
|
Acetylcholine is |
Neurotransmitter that stimulates the muscle fiber to depolarize, which is the signal to start the contractile processes |
|
|
Process of muscular contraction can be best explained by what model ? |
Sliding filament/ swinging cross-bridge model |
|
|
Process of muscular contraction can be best explained by what model ? |
Sliding filament/ swinging cross-bridge model |
|
|
What does Sliding filament\ swinging cross bridge model proposes? |
Muscle shortening occurs due to movement of the actin filament over the myosin filament |
|
|
Excitation-contraction coupling refers to |
Sequence of events in which nerve impulse (action potential) depolarizes the muscle fiber, leading to muscle shortening by cross-bridge cycling |
|
|
The trigger to initiate muscle contraction is |
Depolarization-induced release of calcium from the sarcoplasmic reticulum |
|
|
Muscular contractions occurs via |
The binding of the myosin cross-bridge to actin and the repeated cycling of myosin pulling on the actin molecule resulting in the shortening of the muscle fiber |
|
|
Muscular contractions occurs via |
The binding of the myosin cross-bridge to actin and the repeated cycling of myosin pulling on the actin molecule resulting in the shortening of the muscle fiber |
|
|
Muscle relaxation occurs when |
The motor neuron stops exciting the muscle fiber and calcium is pumped backed into the sarcoplasmic reticulum |
|
|
Removal of calcium from the cytosol causes a position change in tropomyosin, which blocks the |
Myosin cross-bridge binding site on the actin molecule |
|
|
Muscle fatigue |
Decline in muscle power output |
|
|
Causes of exercise-induced muscle fatigue are complex and vary depending upon what? |
Type of exercise performed |
|
|
Muscle cramps |
spasmodic and involuntary skeletal muscle contractions |
|
|
Research indicates that many cases of exercise-associated muscle cramps occur due to |
Abnormal spinal reflex activity that results in hyper active motor neurons |
|
|
Human skeletal muscle fiber types are divided into three general classes of fibers, what are them ? |
Type 1, Type IIx, Type lla |
|
|
Type 1 fibers |
Slow-twitch, slow oxidative fibers |
|
|
Type 1 fibers |
Slow-twitch, slow oxidative fibers |
|
|
Type 11a fiber |
Intermediate fibers, fast oxidative glycolytic fibers |
|
|
Type 1 fibers |
Slow-twitch, slow oxidative fibers |
|
|
Type lla fiber |
Intermediate fibers, fast oxidative glycolytic fibers |
|
|
Type IIx fibers |
Fast-twitch fibers, fast-glycolytic fibers |
|
|
Biochemical properties of muscle fiber types |
Oxidative capacity, type of myosin ATPase isoform, Abundance of contractile protein in the muscle fibers |
|
|
Biochemical properties of muscle fiber types |
Oxidative capacity, type of myosin ATPase isoform, Abundance of contractile protein in the muscle fibers |
|
|
Contractile properties of Muscle fiber types |
Maximal force production, speed of contraction (Vmax), maximal power output, muscle fiber efficiency |
|
|
Successful power athletes (sprinters, power lifters) possess what type of fibers ? |
Large percentage of fast muscle fibers, and therefore a low percentage of slow, type l fibers |
|
|
Successful power athletes (sprinters, power lifters) possess what type of fibers ? |
Large percentage of fast muscle fibers, and therefore a low percentage of slow, type l fibers |
|
|
Endurance athletes posses what type of fibers |
High percentage of slow muscle fibers and a low percentage of fast fibers |
|
|
Isometric |
Muscle exerts force without changing length |
|
|
Dynamic (isotonic) |
Concentric (muscle shortens during force production) eccentric ( muscle produces force but length increases) |
|
|
The amount of force generated during muscular contraction is depending on what factors |
1. Types and number of motor units 2. The initial muscle length 3. The nature of the motor units’ neural stimulation |
|
|
Summation |
The addition of muscle twitches |
|
|
When the frequency of neural stimulation to a motor unit is increased |
Individual contractions are fused in a sustained contraction called tetanus |
|
|
When the frequency of neural stimulation to a motor unit is increased |
Individual contractions are fused in a sustained contraction called tetanus |
