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29 Cards in this Set
- Front
- Back
- 3rd side (hint)
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The plasma membrane of a skeletal muscle cell where some voltage gated Na+ and K+ channels are found. |
Sarcolemma |
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Bundle of myofilaments (the smallest muscle cells) |
Myofibril |
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Internal membrane complex within the sarcolemma |
Sarcoplasmic reticulum. It stores calcium ions. |
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Deep invaginations of the sarcolemma that extend into muscle fiber as a network of.. |
T-tubules (transverse tubules) |
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What are the 3 proteins that compose thin filaments (a type of myofilament that is 5-6nm thick) |
Actin, tropomyosin, & troponin |
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What protein composes thick filaments (a type of myofilament) ? |
Myosin. 200-500 of these protein molecules make it around 11nm thick. |
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Dense fibrous connective tissue surrounding entire muscle |
Epimyseum |
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A bundle of muscle fibers surrounded by perimysium |
A fascicle |
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The contractile unit of a myofibril |
Sarcomere |
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The ability for muscle cells to shorten |
Contactility |
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Neuromuscular junction |
Where a motor neuron transmits the effect of a nerve impulse to the muscle fiber. |
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Motor end plate |
A specialized region of the sarcolemma that has many folds and indentations to increase the membrane surface area covered by the synaptic knob. |
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Perimysium |
Sheath of connective tissue encasing a single fascicle. |
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The distance from 1 Z disk to the next Z disk is called a.. |
Sarcomere |
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During contraction of a muscle, _____ binds to _____ to form a crossbridge |
Calcium ions bind to Troponin |
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Regarding muscle contraction, an action potential causes calcium ions to diffuse from the ____ into the ____ |
Sarcoplasmic reticulum into the Sarcoplasm |
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What is a T-tubule? |
Deep invaginations of the sarcolemma that act as a tunnel into the skeletal muscle. They are voltage-gated Na+ and K+ channels. |
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Endomysium |
Areolar connective tissue |
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Terminal cisternae |
Ring like structures that surround the T-tubules of the sarcoplasmic reticulum. They store calcium and release it during muscle contraction |
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What is an end plate potential? |
The minimum voltage change in the motor end plate that can trigger an opening of voltage gated channels in the Sarcolemma. It initiates an action potential. |
Initiates an action potential |
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A skeletal muscle relaxes when: 4 things occur. |
-an action potential ceases on the sarcolemma -Ca++ is pumped OUT of the sarcoplasm -the tropomyosin covers actin's active sites -a neuron stops firing |
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The synaptic knob contains what type of channel? |
Voltage-gated Ca++ channels |
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A group of skeletal muscle cells that are innervated by 1 neuron is called a: |
Motor unit |
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What type of transport protein are ACh receptors? |
Ligand-gated Na+ channels |
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If ACh secreted into the synaptic cleft isn't removed, then what would occur? |
The muscle would continue to contract even after the brain sent the neural impulse to stop. |
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Large motor units are useful when the muscle that contains them is needed for forceful contraction, or complex movements? |
Forceful contraction. |
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The creatine phosphate/phosphagen system can provide ATP for contracting muscle cells for how long? |
0-10 seconds |
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What does creatine phosphate store in the body? |
A phosphate group |
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Lactic acid fermentation is useful for skeletal muscle cells in what circumstance? |
When the need for ATP is greater than the amount of O2 available |
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