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37 Cards in this Set
- Front
- Back
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What are skeletal muscle fibers comprised of? |
fascicles |
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What are fascicles made up of? |
a group of a muscle fibers |
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What is each skeletal muscle? |
an organ |
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What are the the 2 forms of attachments? (dense regular CT) |
1. tendons 2. aponeuroses |
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What are the three types of connective tissue wrappings? |
1. epimysium 2. perimysium 3. endomysium |
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The entire muscle (composed of fascicles) is surrounded by what? |
epimysium |
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Each fascicle (group of muscle fibers) is surrounded by what? |
perimysium |
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Each muscle fiber is wrapped by what? |
endomysium |
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Each myofiber (cell) is composed of what? |
myofibrils |
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Each myofibril is composed of what? |
myofilaments |
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what do thick myofilaments contain? |
the protein myosin |
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what do thin myofilaments contain? |
primarily the protein actin |
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what is the muscle cell membrane called? |
sarcolemma |
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what is the muscle fiber cytoplasm called? |
sarcoplasm |
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what is the muscle fiber endoplasmic reticulum called? |
sarcoplasmic reticulum |
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what cellular organells do muscle fibers contain? |
lysosomes and ribosomes |
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what is the function of the sarcoplasmic reticulum? |
storing and releasing Calcium ions (Ca++) as needed for muscle contraction |
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What is the function of transverse tubules (T-tubules)? |
can conduct a nerve impulse rapidly to the interior of the muscle cell there also act as a means of getting nutrients into the cell and waste products out |
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What is a sarcomere? |
contractile unit of myofibril |
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What are the 4 striation/banding patterns? |
I-bands, A-bands, Z-line, H-zones |
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Which myofilaments are associated with I-bands? |
thin myofilaments only |
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Which myofilaments are associated with A-bands? |
thick and thin myofilaments |
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What are Z-lines? (Z-discs) |
dark line in the middle of an I-band |
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Which myofilaments are associated with H-zones? |
only thick myofilaments |
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What are H-zones? |
a lighter, central region in the middle of an A-band |
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where do sarcomere's run? |
from Z-line to Z-line |
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What is one type of contraction of a skeletal muscle? |
sliding filament model of contraction |
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What happens during sliding filament model of contraction? |
-muscle stimulated by a nerve -thick and thin myofilaments slide over one another -length of each sarcomere shortens, muscle contracts |
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What is the 1st step in the sliding filament model of contraction? |
1. Nerve impulse carried from brain/spinal cord to muscle by the axon of a motor neuron. |
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What is the 2nd step in the sliding filament model of contraction? |
2. Axon meets muscle fiber at the neuromuscular junction (myoneural junction) |
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What is the 3rd step in the sliding filament model of contraction? |
3. Axon releases a chemical neurotransmitter called acetylcholine, which binds to sarcolemma |
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What is the 4th step in the sliding filament model of contraction? |
A nerve impulse is generated in the sarcolemma and it passes down the T-tubules. As a result, the sarcoplasmic reticulum releases calcium ions (Ca++) |
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What is the 5th step in the sliding filament model of contraction? |
5, Calcium ions (Ca++) bin to thin myofilaments |
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What does calcium ions binding to thin myofilaments help with? |
this helps thick myofilaments attach to the thin myofilaments |
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what is the 6th step in the sliding filament model of contraction? |
6. Myofilaments slide over one another; sarcomere shortens; muscle contracts |
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What is the 7th step in the sliding filament model of contraction? |
When the nerve impulse stops, Ca++ returns to the sarcoplasmic reticulum and the myofilaments slide back to their resting state |
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Where are calcium ions stored? |
In the sarcoplasmic reticulum |
