Term
| space between the motor neuron and the motor end plate; also the space that Ach is released into |
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Definition
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Term
| by what method is is Ach released into the synaptic cleft? |
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Definition
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Term
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Definition
| motor end plate on the sarcolemma |
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Term
| functions in movement, heat generation, posture, and joint stabilization |
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Definition
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Term
| the 3 muscle types all contain this |
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Definition
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Term
| all 3 muscle types have this common function |
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Definition
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Term
| individual skeletal muscle cells(fibers) are wrapped in |
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Definition
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Term
| when epimysium itself is fused to bone or cartilage the attachment is known as |
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Definition
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Term
| the attachment site at the movable bone is known as |
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Definition
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Term
| specialized plasma membrane of skeletal muscle cells |
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Definition
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Term
| invaginates into T-tubules at A band I band junction |
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Definition
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Term
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Definition
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Term
| rod like structures contained within skeletal muscle cells that are made of myofilaments and associated proteins |
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Definition
| myofibrils (an organelle) |
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Term
| made mostly of actin and regulatory proteins |
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Definition
| thin filaments (a type of myofilament) |
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Term
| what 4 banding patterns on the myofibrils are responsible for striations? |
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Definition
| A band, I band, H zone, Z disk |
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Term
| lighter region in center of each A band which lacks thin filaments when muscle fibers are relaxed |
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Definition
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Term
| cylindrical protein that blocks myosin binding sites on actin to prevent myosin binding |
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Definition
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Term
| organelles that act as contractile elements in skeletal muscle cells |
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Definition
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Term
| smooth endoplasmic reticulum of muscle cells that forms a network for tubules around each myofibril in muscle cell |
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Definition
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Term
| anchors actin (thin filaments) |
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Definition
| nebulin (which makes up the Z disk) |
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Term
| proposed mechanism of contraction that states that during contraction actin slides past myosin causing overlap, while myosin stays mostly still |
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Definition
| sliding filament model/theory |
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Term
| I bands do what during muscle contraction due to the sliding of actin? |
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Definition
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Term
| H zones do what during muscle contraction due to the sliding of actin? |
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Definition
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Term
| thin filament sliding is mediated by _____ attaching, ratcheting, and detaching from actin filaments |
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Definition
| cross bridges(myosin heads) |
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Term
| tropomyosin blocks myosin binding sites on actin when? |
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Definition
| when intracellular Ca2+ levels are low |
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Term
| What is it called when you have a junction between a motor neuron's branched axonal terminal and a skeletal/cardiac muscle cell? |
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Definition
| a neuromuscular junction (nm junction) |
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Term
| Describe the events at the nm junction leading to sarcolemma action potential and skeletal muscle contraction in 6 steps. |
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Definition
1. Action potential arrives at axon terminal of the motor neuron.
2. Voltage gated Ca2+ Channels open and Ca2+ enters the axon terminal.
3. Ca2+ entry causes synaptic vesicles to release Ach by way of exocytosis.
4. Ach diffuses across the synaptic cleft and binds to receptors in the sarcolemma.
5. Ach binding opens ion channels that allow simultaneous passage of Na+ into muscle cells and K+ out.
6. Ach effects are terminated by its enzymatic breakdown in the synaptic cleft by acetylcholine esterase. |
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Term
| action potential is an electrical impulse generated by rapid influx of what? |
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Definition
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Term
| Rapid Na+ flow into the cell causes _____ of membrane above the threshold level. |
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Definition
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Term
| At how many mV do Ach receptors open up to post synaptic membrane depolarization? |
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Definition
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Term
| From the action potential on the sarcolemma, to the sliding myofilaments, to muscle contraction is all known as what process? |
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Definition
| excitation contraction coupling |
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Term
| small, spindle shaped cells with single nuclei, also called "muscle fibers", not striated |
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Definition
| smooth muscle cells (fibers) |
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Term
| junction with no motor end plate for neurotransmitters |
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Definition
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Term
| most hollow organs have how many sheets of smooth muscle? |
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Definition
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Term
| in cardiac muscle a signal from the autonomic nervous system causes excitation or inhibition? |
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Definition
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Term
| The arteries and the GI tract are examples of this |
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Definition
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Term
| these display autorhythmicity |
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Definition
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Term
| How does contraction speed of cardiac muscle compare to that of skeletal muscle? |
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Definition
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Term
| this makes up wall of hollow organs |
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Definition
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