Term
| What are the three types of muscle? |
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Definition
| skeletal, cardiac and smooth. |
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Term
| What are the functional characteristics of muscle tissue? |
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Definition
1.)Excitability or irritability - ability to receive and respond to stimuli.
2.)Contractility - the ability to shorten forcibly.
3.)Extensibility - the ability to be stretched or extended.
4.)Elasticity - the ability to recoil and resume original resting length. |
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Term
| How are skeletal and smooth muscles cells similar? |
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Definition
| they are elongated and called muscle fibers. |
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Term
| What 2 myofilaments does contraction depend on? |
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Definition
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Term
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Definition
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Term
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Definition
| Cytoplasm of a muscle cell. |
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Term
| What are skeletal muscles responsible for? |
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Definition
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Term
| What is cardiac muscle responsible for? |
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Definition
| Coursing blood through the body. |
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Term
| What is smooth muscle responsible for? |
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Definition
| Maintain blood pressure, squeezes/propels substances through organs. |
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Term
| What are some miscellaneous muscle functions? |
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Definition
| Maintaining posture, stabilizing joints, generating heat. |
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Term
| What is skeletal muscle packaged in and attach to? |
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Definition
| Skeletal muscle tissue and attach to and cover the bony skeleton. |
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Term
| What are the obvious stripes in skeletal muscle and what are they composed of? |
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Definition
| Striations made of proteins. |
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Term
| Are skeletal muscles voluntary or involuntary? |
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Definition
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Term
| How do skeletal muscles contract? Do they tire easily? |
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Definition
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Term
| Skeletal muscle is extremely _________ and can exert forces ranging from a fraction of an ounce to over 70 lbs. |
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Definition
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Term
| Is cardiac muscle voluntary? |
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Definition
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Term
| What is the frequency of it's contractions and is set by what? |
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Definition
| Fairly steady and set by heart's pacemaker. |
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Term
| ______ _______ allow the heart to respond to changes in bodly needs. |
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Definition
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Term
| Is smooth muscle striated, involuntary or voluntary? |
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Definition
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Term
| What are the three connective sheaths of skeletal muscle? |
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Definition
Endomysium - surrounds each muscle fiber
Perimysium - surrounds fascicles
Epimysium - surrounds entire muscle |
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Term
| Most skeletal muscles span joints and are attached to bone in at least ____ spaces. |
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Definition
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Term
| The insertion moves ______ the ______. |
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Definition
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Term
| Muscles attach ______ & _______. |
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Definition
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Term
| What is a direct attachment? |
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Definition
| Epimysium of the muscle is fused to the periosteum of a bone. |
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Term
| What is an indirect attachment? |
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Definition
| Connective tissue wrappings extend beyond the muscle as a tendon or aponeurosis. |
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Term
| Each muscle is served by _____ nerve, _____ and ______. |
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Definition
| one nerve, one artery, one or more veins. |
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Term
| Each skeletal muscle fiber is supplied with a _____ _____ that controls contraction. |
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Definition
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Term
| Contracting fibers require _____ ______ __ ________ and _______. |
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Definition
| continuous delivery of oxygen/nutrients |
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Term
| Wastes are removed via ______. |
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Definition
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Term
| Skeletal muscles are stimulated by ____ _____ of the ______ nervous system. |
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Definition
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Term
| Axons of these neurons travel in ______ to ______ cells. |
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Definition
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Term
| Axons of motor neurons ______ as they enter muscles. |
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Definition
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Term
| Each axonal branch forms a __________ ______ with a single muscle fiber. |
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Definition
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Term
| Neuromuscular junction is formed from _____ ______& ____ _____ ______ of a muscle. |
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Definition
| Axonal endings/ motor end plate. |
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Term
| Skeletal muscle fibers are short, cuboidal cells with 1 nucleus on top of the sarcolemma. TRUE OR FALSE? |
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Definition
| FALSE! Long, cylindrical, multinucleated cells beneath the sarcolemma. |
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Term
| Are fibers wider than they are long or vice versa? |
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Definition
| Fibers are 10-100 mm in width and up to hundreds of centimeters long. |
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Term
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Definition
| Produced by the fusion of embryonic cells. Multinucleated. |
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Term
| What are the glycosomes and myoglobin in sarcoplasm? |
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Definition
Glycosomes - associated with cell metabolism. Forms organelles.
Myoglobin - monomeric heme protein found in muscle tissue and is used as a storage site for oxygen. |
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Term
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Definition
| densely packed, rodlike, contractile elements. Make up most of muscle volume. |
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Term
| What are sacromeres and where are the found? |
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Definition
| Smallest contractile unit of a muscle. Region of a myofibril between two successive Z discs. |
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Term
| What are the two types of microfilaments? |
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Definition
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Term
| What is the difference between thick and thin filaments? |
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Definition
Thick - extend the entire length of A band.
Thin - extend across the I band and partway into the A band. |
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Term
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Definition
| coin shaped sheet of proteins that anchors the thin filaments and connects myofibrils to one another. |
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Term
| Do thin filaments overlap thick filaments in the lighter H zone? |
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Definition
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Term
| Why do M lines appear darker? |
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Definition
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Term
| What are thick filaments composed of? |
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Definition
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Term
| What does each myosin molecule contain? |
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Definition
| A rod-like tail and two globular heads. |
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Term
| What are the tails of a myosin molecule made of? |
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Definition
| Two interwoven, heavy polypeptide chains. |
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Term
| What are the heads of a myosin molecule made of? |
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Definition
| Two smaller, light polypeptide chains called cross-bridges. |
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Term
| What are thin filaments made of? |
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Definition
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Term
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Definition
| Helical polymer of globular subunits called G actin. |
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Term
| What are the subunits of actin? |
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Definition
| They contain active sites to which myosin heads attach to during contraction. |
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Term
| What are regulatory subunits bound to actin? |
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Definition
| Tropomyosin and troponin. |
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Term
| What is the sarcoplasmic reticulum? |
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Definition
| An elaborate, smooth endoplasmic reticulum that most runs longitudinally and surrounds each myofibril. |
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Term
| What forms perpendicular cross channels? |
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Definition
| Paired terminal cisternae |
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Term
| What is the function of the SR? |
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Definition
| Regulation of intracellular calcium levels. |
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Term
| What are T tubules and their function? |
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Definition
| Elongated tubes that penetrate into the cell's interior at each A band I band junction. |
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Term
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Definition
| T tubules associated with paired terminal cisternae |
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Term
| What do t tubules conduct? |
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Definition
| Impulses to the deepest regions of the muscle. |
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Term
| What do t tubules signal for? |
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Definition
| The release of Ca2+ from adjacent terminal cisternae. |
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Term
| In order to contract, a skeletal muscle must: |
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Definition
1.)Be stimulated by a nerve ending.
2.)Propogate an electrical current, or action potential, along its sarcolemma.
3.)Have a rise in intracellular Ca2+ levels, the final trigger for contraction.
4.) Linking the electrical signal to the contraction is excitation-contraction coupling. |
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Term
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Definition
| Binds its receptors at the motor end plate which opens chemically gated channels, Na+ and K+ diffuse out and the interior becomes less negative and becomes DEPOLARIZED. |
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Term
| What enzyme destroys Ach? |
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Definition
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Term
| What does the destruction prevent? |
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Definition
| Continued muscle fiber contraction in the absence of additional stimuli. |
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Term
| What are the 4 things that happens once an action potential is generated? |
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Definition
1.)Propogated along sarcolemma
2.)travels down t tubules
3.)triggers ca+2 release from terminal cisternae
4.)Ca2+ binds to troponin |
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Term
| Once Ca2+ is bound to troponin, what does this cause? |
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Definition
| The blocking action of tropomyosin to cease and actin active binding sites are exposed. |
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Term
| Myosin cross bridges alternately attach and detach. Then what? |
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Definition
| Thin filaments move towards the center of the sarcomere. Hydrolysis of ATP powers this cycling process. Ca2+ is removed into the SR, tropomyosin blockage is restored and the muscle fiber relaxes. |
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