Term
physiological events occur during the:
a) contraction interval b) latency period and c) relaxation interval |
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Definition
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A.is theperiod which actin and myosin filaments are sliding past one another
b. period which the folling event occur:
1. action pot. AP moves dwn axon and into the terminal
2. actyl col Ach is released fr. The terminal
3. ach diffuses across the cleft
4. Ach binds to the post sunaptic receptor Na Channel
5. Na Flows into the muscle cells
6. Muscle cell mem is depolarized past threshold
7. AP moves along the mem. And into the t-tubes
8. Depolar. Of the mem causes the rel. of Ca fr. The sarcoplasm reticulum inc Ca causes myofil. To slide
c. period during which Ca is pumped back into SR
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Term
| a) threshold stimulus for a muscle contraction b) suprathreshold stimulus c) submaximal stimulus and d) maximal stimulus. |
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Definition
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a. amt of voltage ness. To elict a resp. fr. The mus.
b. amt of voltage ness to elict resp. b/t threshol and max. resp
c. amt of stimules ness to elict mac. Resp.
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Term
Difference between summation and tetany?
What physiological events underlie these phenomena?
What is their functional significance? |
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Definition
Sum: rapid stimulation that does not allow a mus relax and causes inc. force gen. up to a state of max. contract. (tet)
Summation is causes by inc amt of Ca lest in the sarcoplams after ea. Contraction. Sum. Allows for a graded range of contract. Ampli. From ea. Mus fiber
Tetany: maximal, cont cantract. During tetany all mus fibers are completely contract. This behavior allows for a sustained contracr and the constant dev. Of force by the mus
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Term
| length-tension relationship? What is its functional significance? |
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Definition
| Length vs tension rel relates force gen. w/initial mus length. As mus length is inc above or dec. below the optimal length range there is a dec. in the force of contraction gen. by the mus. The relation. Reveals there is optimal length range for a mus. |
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Term
| How is muscle normally stimulated to contract? Which would you expect to be more efficient, stimulating a muscle directly or stimulating the nerve that innervates the muscle? Explain. |
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Definition
| The muscle is normally stimul. To contract. Through nerve. This is more efficient as the nerve is a smaller piece of tissue to stiml. And therefore req. less stimul. Energyand it branches throughout mus. |
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Term
| What occurs during fatigue? |
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Definition
Mus can no longer gen. or sustain force. In extended contract. Fatigue is ass. w/: 1.Depletion of glycogen stores in short duration max. exertion fatigue results fr.: 2.Inc. prod of inorganic phosphate as ATP is converted to ADP. Inc by p slows the rel. of P fr. Myosin =alters the powerstroke 3.Also, inc extracell. K as a result of APS, shifts the membrane put and decreases the release of Ca to SR |
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Term
| Describe the sequence of events that occurs from the time acetylcholine is released from the motor neuron to the time the muscle fiber contracts. |
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Definition
1.Ach diffuses across. The cleft
2.Ach binds to the postsynaptic receptor (Na Chan.)
3.Na flow into the mus cells 4.Mus cell mem is depolar. Past threshold
5.AP moves along the mem. And into the t-tubes
6.Depolar. Of mem. Cuses release of Ca to SR
7.Inc. Ca causes myofiliments to slide |
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Term
| Describe the morphology of a muscle from gross anatomy to myofilaments. |
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Definition
-Epimysium surrounds whole mus
-Perimsium surrounds the fascicles of the mus fibers -Endo surrounds the induv. Mus fibers
-Ea. Mys fibers = single mus cell
-Ea. Mus fiber = many organelles = myofibrils
-Ea. Myfibril = contains many myofibrils |
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Term
| Describe the difference in histological appearance between a skeletal muscle fiber and a smooth muscle. |
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Definition
| -A skel. Mus fiber is striates in appearance b/c of the regular arrange. Of myofilaments. It also = multinucleate w/ nuclei located along the edge of the cell b/c cytoplasm is filled w/ myofibrils Smooth mus. Has single nucleus and myofilaments that have a reg. orientation (unstriated) |
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Term
| How is the action potential in the skeletal muscle cell membrane functionally connected to the release of Ca from the SER (or sarcoplasmic reticulum)? |
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Definition
| Potential change AP in the mem of the tube causes the DHP molec. To change shape This molec is conn. To the ryanodine moelc. (Ca chann) in the SER mem The interact. b/t the 2 moelc. Cause the Ca chann to open ahd the Ca rel in the cytocol |
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