Term
| Which bands shrink during contraction? What is in the middle of those lines? |
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Definition
-HI
-H has the M line, I has the Z line
-Think H heavy, M myosin |
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Term
| What are the two proteins that also complex with the actin? What is their role? |
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Definition
-Troponin and tropomyosin
-Ca2+ binds to the troponin and causes myosin to bind actin |
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Term
| What is the receptor that senses the voltage change in the muscle cell and how does it respond? |
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Definition
-DHP receptor
-It responds by opening the sarcoplasmic reticulum up, allowing Ca2+ to spill out, which then hooks up with troponin and initiates contraction |
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Term
| What is the neurotransmitter for muscle action? Where is it released on the muscle cell? |
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Definition
-Acetylcholine (Ach)
-At the motor end plate |
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Term
| What is a tetanic contraction? |
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Definition
-When the impulses are so close that the force runs together as a constant value
-Complete at maximum contraction |
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Term
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Definition
| -They connect the myofilaments to each other and to the membrane in smooth muscle cells |
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Term
| How does the myosin get the energy added to it in order to perform its motor functions? What takes the energy off? |
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Definition
-Ca2+ activates calmodulin (CaM)
-CaM activates Myosin light chain kinase (MLCK)
-MLCK phosphorylates myosin
-The end result is increased muscle tension?
-When Ca2+ is not around, the system runs in reverse and myosin phosphatase removes the phosphate from myosin |
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Term
| What comes through the ligand-gated nicotinic channel to initiate the Ca2+ release from the SR? |
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Definition
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Term
| Describe type I & II motor units? |
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Definition
-Type I; have few fibers of moderate diameter, low force, perform oxidative metabolism, and have low fatigability
-Type II; many fibers of large diameter, high force, more anaerobic, high fatigability |
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Term
| What happens to force, velocity, and shortening capacity if we put more sarcomeres in parallel (side by side), as opposed to in a series (end to end)? |
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Definition
| -Side by side gives us more force and end to end gives us more velocity and shortening capacity. |
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