Term
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Definition
| Cords of elastic connective tissue that transmit force from muscle to bone |
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Term
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Definition
| Bundles of individual muscle cells surrounded by cell tissue |
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Term
| What do muscle fibers have many of that most cells only have one of? |
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Definition
| Many nuclei and mitochondria |
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Term
| What is a sarcolemma analogus to? |
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Definition
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Term
| What is the sarcoplasm analogus to? |
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Definition
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Term
| What are the components of myofibrils? |
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Definition
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Term
| What are the terms for thick and thin filaments, respectively? |
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Definition
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Term
| What is the function of the sarcoplasmic reticulum? |
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Definition
| A sac that stores calcium ions |
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Term
| What is the function of T tubules? |
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Definition
| To transmit signals from the sarcolemma to the myofibrils |
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Term
| What are sarcomeres bordered by? |
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Definition
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Term
| In a sarcomere, what are thick filaments connected by? |
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Definition
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Term
| What band spans the length of thick filaments and the six thin filaments around them? |
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Definition
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Term
| What is the space in the middle of an A band, and why does it appear lighter? |
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Definition
| The H zone; it is missing thin filaments |
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Term
| What occupies the space between A bands? |
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Definition
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Term
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Definition
| Thin filaments and the Z line that connects them |
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Term
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Definition
| A long fibrous molecule that extends over actin to block the myosin-binding sites at rest |
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Term
| What is the functions of the three proteins on troponin? |
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Definition
1. Attatches to actin strand, inhibitory (I),
2.Binds to tromyosin,(T)
3. contains the calcium binding site (C) |
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Term
| What are the two sites on a myosin head? |
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Definition
| An actin-binding site and an ATP-ase site that hydrolyzes ATP |
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Term
| What is the function of titin? |
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Definition
| To anchor actin to myosin and to exert an opposite force as sarcomeres lengthen so muscle fibers shorten |
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Term
| What areas of a sarcomere shorten during muscle contraction? |
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Definition
| The I band and H zone (thin filaments slide past thick) |
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Term
| When is the high energy form of myosin? |
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Definition
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Term
| When is the low energy form of myosin? |
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Definition
| After releasing the ADP after power stroke |
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Term
| When does myosin hydrolyze an ATP? |
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Definition
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Term
| When does myosin release an inorganic phosphate? |
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Definition
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Term
| What immidiately precedes a powerstroke? |
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Definition
| Myosin releasing an inorganic phosphate |
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Term
| When does myosin release an ADP? |
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Definition
| After the crossbridge cycle |
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Term
| When does a new ATP attatch to myosin? |
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Definition
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Term
| What ion is required for the binding of actin and myosin? |
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Definition
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Term
| Define excitation-contraction coupling |
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Definition
| The events that link an action potential to the contraction |
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Term
| As an action potential travels down Transverse tubules, what are activated? |
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Definition
| voltage-sensitive L-type Ca2+ channels |
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Term
| What do L-type Ca2+ channels link to and stimulate, and what is its function? |
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Definition
| Ryanodine, to allow calcium to flow out of the SR |
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Term
| What is the effect of calcium binding onto a troponin? |
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Definition
| Tropomyosin shifts, exposing the myosin-binding sites |
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Term
| What causes calcium reuptake in skeletal muscle? |
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Definition
| Ca-ATPase pumps Ca2+ back into the SR |
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Term
| What causes the "burn" during exercise? |
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Definition
| Accumuation of lactic acid |
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Term
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Definition
| An increase in the number of active motor units |
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Term
| Define the size principle |
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Definition
| Both smaller motor units and smaller motor neurons are activated first |
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Term
| What kind of muscle has no stritations? |
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Definition
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Term
| Name three functions of smooth muscle |
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Definition
| Peristalsis, vasoconstriction, and vasodialation |
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Term
| Why does smooth muscle lack stritations? |
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Definition
| Thick and thin filaments are not arranged in sarcomeres |
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Term
| Define pacemaker potentials |
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Definition
| Slow depolarizations caused by increased sodium, increased calcium, or decreased potassium permeability |
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Term
| Which muscle types have gap junctions? |
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Definition
| Single-unit smooth and cardiac |
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Term
| Can muscle fibers repair themselves if injured? |
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Definition
| Muscle fiber cell division stops at birth, however, fibers can increase in size. If muscle cells are injured, satellite cells can differentiate into muscle cells after birth. |
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Term
| How are thin filaments oriented around thick ones within a myofibril? |
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Definition
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Term
| During a muscle contraction, what bands shorten? |
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Definition
| I-band shortens, but A-band length does not change, thick and thin filaments slide past each other, but thick and thin filaments do not shorten. |
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Term
| What causes rigor mortis? |
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Definition
| If no ATP is available, the cross bridge remains attached to the actin producing rigor mortis. Rigor mortis peaks approximately 12 hrs after death and disappears 48-60 hrs after death due to break down of muscle. |
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Term
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Definition
| enlargements at the end of sarcoplasmic reticulum and is associated with the transverse tubule. |
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Term
| How long is a muscle twitch? |
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Definition
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