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32 Cards in this Set
- Front
- Back
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sarcoplasmic reticulum (SR) |
functions in the regulation of intracellular Ca 2+ levels |
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T tubules |
continuous with sarcolemma, associate with the paired terminal cisternae to form triads that encircle each sacromere |
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T tuble proteins |
voltage sensors |
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SR foot protens |
gated channels that regulate CA 2+ release from the SR cisternae |
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shortening sacromeres |
responsible for skeletal muscle contraction |
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during relaxation |
sarcomeres lengthen because of some external force, like contraction of antagonistic muscles |
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t tubules conduct |
impulses deep into muscle fiber |
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requirements for skeletal uscle contration |
Activation, excitation- contaction coupling |
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activation |
neural stimulation at a neuromuscular juction |
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excitation- contraction coupling |
generation and propagation of an action potential along the sarcolemma |
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final trigger in skeletal muscle contraction |
a brief rise in intracellular Ca 2+ levels |
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neuro muscular junction synapse |
axon terminal resting in an invagination of the sarcolemma |
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(NMJ ) PRESYNAPTC TERMINAL |
axon terminal with synaptic vesicles |
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snaptic cleft |
space |
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post synaptic membrane or motor end plate |
sarcolemma |
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synaptic vesicles |
neurotransmitter acetylcholinesterase |
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neurotransmitter |
substance released from a presynaptic membrane that diffuse across the synaptic cleft ans stimulates or inhibits the production of an action potential in the postsynaptic membrance
(ACETYLCHOLINE) - a synaptic vesicle |
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acetylcholinesterase |
a degrading enzyme in synaptic cleft. Prevents accumulation of ACH - a synaptic vesicle |
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nervous system |
controls muscle contration through action potentials |
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resting potential |
must exist for action potential to occur |
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ion channels |
ligand gated, voltage gated (specific for certain ions) |
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ligand gated |
ligands are molegules that bind to receptors
ex. ACh ( neurotransmitter) |
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receptors |
protein , glycoprotein with a receptor site |
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voltage gated |
open and close in response to small voltage changes |
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action potentials |
depolarization repolarization |
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depolarization |
inside of plasma membrane becomes less negative, if change reaches treshold, depolarization occurs |
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repolarization |
-return of resting membrane potential, - the membrane potential drops lower that its resting potential then revounds bc Na + and K+ together are higher.....then Na/K+ restores resting potential. |
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excitation-contraction couplin |
mechanism where an action potential causes muscle fiber contraction |
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Excitation - contraction coupling |
1. sarcolemma 2. transverse T tubles 3. terminal cisternae 4. terminal cisternae 5.sarcoplasmic reticulumn ; smooth ER 6. Triad T tuble; two adjacent terminal cisternae 7. Ca 2+ Troponin and Tropomyosin |
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when an action potential is produced at the neuromuscular juction and propragated along the sarcolemma.....depolarization spreads along the membrane of the T tubles. Then... |
the depolarization of the T tubles causes gated Ca 2+ channels in the sarcoplasmic reticulum to open, resulting in an increases in Ca 2+ in ther sarcoplasmic reticulum and terminal cisternae. Ca ions then diffuse from the sarcoplasmic reticulum into the sarcoplasm. |
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After Ca + diffuse from the sarcoplasmic reticulum into the sarcoplasm |
calcium ions released from the sarcuoplasmic reticulum bind to troponin molecules. The troponin molecules bound to G actin molecules and are releases causing tropomyosin to move, exposing the g active sites |
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after the tropomyosin move |
the active sites on g actin molecules are exposed, the heads of the myosin myofilaments bind to them to form cross- bridges |
