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27 Cards in this Set
- Front
- Back
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What is the Largest Tissue of Body? |
Muscle |
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What are the 3 Types of Muscles? |
Skeletal Cardiac Smooth |
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Describe the 3 Types of Muscles |
Skeletal- striated, multinucleated, and voluntary
Cardiac- striated, mono nucleated (one nuclei), and involuntary
Smooth- un-striated, mono nucleated (one nuclei), and involuntary |
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What is the function of muscle contractions? |
Movement Digestion and (mechanical workings) transportation of excess waist from inside to outside the body |
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Structure of Skeletal Muscles |
Has connective tissues that surrounds and binds bundles of muscle fibers
Muscle fibers run parallel to each other |
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Describe a Muscle Fiber |
Single, striated, and multinucleate Cylindrically, elongated, and long extend entire length of muscle |
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Myofibrils |
Contained in muscle fiber contractile element of the muscle fiber
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What do Myofibrils contain? |
Proteins thick filament (myosin) and thin Filament (actin) They alternate dark (A band) and light (I bands)= appearance of sarcomere
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What is a Sarcomere and what does it contain? |
Sarcomere from Z-line to Z-line Contains A-band, I-band, M-line, and H-zone |
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What is the A-band? |
Where thick (myosin) and thin (actin) filaments cross/meet during contraction |
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What is the M-Line? |
Located in the middle of H-zone which is in the middle of A-band |
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What is H-zone? |
Area where thick (myosin) filaments do not reach Middle of A-band Contains only thin filaments |
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What is I-band? |
Remaining portion of thin (actin) filaments that don't go into A-band |
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What is Titin? |
It is a large elastic protein that extends in both direction of M-line along the length of thick (myosin) filament to Z-line at opposite ends of a sarcomere |
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What is the function of Titin? |
Stabilizes thick (myosin) filament in relation to then augments muscle elasticity (like a spring) |
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What is Myosin? |
a component of thick filament |
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What does Myosin contain? |
Myosin contains protein molecules like golf clubs (identical subunits) Globular heads (two of them) are extended outwards one each side The tails intertwine and mingle with each other in the middle (between globular heads) |
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What sites does the globular heads contain? |
Globular heads contain two sites: One-> actin binding site Two-> a myosin ATPace site (splits ATP) These are also cross-bridges for thick and thin filaments |
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What is Actin? |
A component of thin filament |
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What does Actin contain? |
Actin has actin molecules that contains special binding sites for attachment with myosin cross-bridge Contains Tropomyosin and Troponin |
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The binding of what results in the contraction of muscle fibers? |
Binding of molecules |
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Actin and Myosin are known as what proteins? |
Contractile (however neither contracts, they just cause the muscle fiber to contract)
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Are Actin and Myosin unique to muscle cells? |
No, but they are most abundant in muscle cells |
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What does Tropomyosin do? |
Tropomyosin are thread like molecules that extend from end to end alongside the groove of actin It covers the binding site which then blocks the interaction of actin and myosin so it prevents muscles to contract |
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What does Troponin do? |
Troponin has 3 polypeptides. One binds to the actin-binding site One binds to actin The other binds with CA2+ (calcium ions) when available |
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What does Troponin do when there is a lack of CA2+? |
Troponin continues to keep thick (myosin) filament in place over the actin-binding site. This prevents actin and myosin from connecting which results in no muscle contraction
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What happens when Troponin binds to CA2+? |
When Troponin binds to CA2+, it allows tropomyosin to move away from actin-binding sites. This allows actin and myosin to connect and therefore allows muscle contraction |
