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26 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Contractability |
Ability of muscle to contract |
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Excitablility |
Ability of muscle to react to electrical stimuli |
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Extensibility |
Muscle can be stretched beyond normal length and can still contract |
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Elasticity |
Muscle can spring back to original length after it has been stretched. |
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Perimesyum |
Connective tissue that surrounds the fascicles. |
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Epimysium |
Surrounds entire muscle. |
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Motor neurons |
Cells responsible for stimulating skeletal muscle contraction |
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Myoblasts |
Muscle fibers develop from less mature cells called ___________. |
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Sarcoplasmic Recticulum |
Smooth endoplasmic reticulum of muscles |
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Sarcoplasmic Recticulum |
Smooth endoplasmic reticulum of muscles |
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Sarcolemma |
Action potentials occur here, plasma membrane of muscle fiber. |
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Z disk |
Forms stationary anchor for attachment of actin myofilaments |
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I bands |
Light staining bands, includes a Z disk, extends to the ends of the myosin myofilaments |
AKA isotropic bands |
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M line |
Helps hold myosin myofilaments in place |
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Actin myofilaments |
Composed of 2 strands of F actin, tropomyosin, & troponin. Each G actin monomer has an active site, where myosin binds. |
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What happens when a sacromere contracts? |
A bands, myosin and actin stay the same. H zone, I band & sacromere shorten.
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What happens when a muscle relaxes? |
Actin & myosin overlap, and the H zone is visible. Sacromere is at it's normal resting length. |
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What are the functions of the muscular system? |
Body movement, posture, respiration, communication, contraction of heart, production of body heat, construction of organs &a blood vessels. |
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What is the sliding filament model? |
When a muscle contracts, actin & myosin myofilaments slide past each other, but remain the same length. |
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What is resting membrane potential? |
Concentration of K+ inside the plasma membrane is higher than outside. The concentration of Na+ is higher outside than inside. & the plasma membrane is more permeable to K+ than to Na+ |
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Isometric contractions |
Muscle length does not change |
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Isometric contractions |
Muscle length does not change |
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Isotonic contractions |
Force is generated, muscle lengthens |
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Concentric isotonic contractions |
Muscle shortens |
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Eccentric isotonic contractions |
Muscle lengthens |
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What is a motor unit? How does it affect muscle control? |
A motor unit is a single motor neuron and all the muscle fibers it innervates. Having many small motor units allows for a great deal of control. |
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