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27 Cards in this Set
- Front
- Back
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Define: Striated Muscle cells
What are the 2 types of striated muscle cells? |
characteristic - alterations of light and dark cross-bands (absent in smooth muscle)
Skeletal and cardiac |
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Define: Skeletal muscle
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striated
account for most voluntary muscle mass of the body |
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Cardiac muscle
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striated
involuntary limited almost exclusively to the heart |
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Define: Smooth muscle cells
Where are they located? |
no regularly repeating arrangement of myofibrillar contractile proteins (myofilaments)
walls of blood vessels and viscera, dermis of skin |
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Sarcolema
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muscle cell membrane
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sarcoplasm
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muscle cytoplasm
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sarcoplasmic reticulum
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smooth endoplasmic reticulum of muscle
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sarcosomes
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muscle cell mitochondria
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muscle fiber
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muscle cell - called a muscle fiber because the cells are much longer than they are wide.
It is a LIVING entity |
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What are all 3 muscle types derived from?
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mesoderm
cardiac - splanchnopleuric mesoderm smooth - splanchnic and somatic mesoderm skeletal - somatic mesoderm |
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What is skeletal muscle composed of?
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long, cylindrical, multinucleated cells that undergo voluntary contraction
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What are myotubes made of?
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myoblasts that line up end to end during embryonic development and fuse with each other.
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What do myotubes do?
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manufacture cytoplasmic constituents as well as contractile elements called myofibrils.
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What are myofibrils composed of?
What is their function? Diameter? How are they arranged? |
arrays of myofilaments- proteins
Responsible for the contractile ability of the cell 1-2 micro meters Parallel - responsible for cross striations of light and dark banding |
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What is the diameter (range) of a muscle fiber?
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10-100 micro meters- but when hypertophied they can get even bigger.
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How are capillaries arranged in muscle fibers?
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parallel within intervening intercellular spaces.
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What does the strength of an individual muscle fiber vs the strength of a whole muscle depend on?
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fiber - on diameter
muscle - # and thickness of it's components |
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What color is skeletal muscle and why?
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Pink/Red because it is rich with blood vessels and myoglobin pigments.
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What determines whether a skeletal muscle will be classified as RED, WHITE or INTERMEDIATE?
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diameter
quantity of myoglobin # mitochondria extensiveness of sarcoplasmic reticulum concentration of various enzymes rate of contraction |
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Can any muscle be composed of completely one type of fiber?
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No - usually all muscles have their unique proportions of red, white and intermediate fibers.
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Red/white skeletal muscle fiber has a lot or a little of each of these?:
blood vessels mitochondria myoglobin enzymes |
a lot! Except for ATPases, it has a lot of oxidative enzymes tho.
*opposite is true for white muscle fibers - a lot of phosphorylases and ATPases* |
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Are these big or small in red/white skeletal muscle fibers?
nerves fiber diameter |
small
*opposite for white muscle fibers* |
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What is red muscle/white fiber contraction like?
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slow but repetitive, not easily fatigued, weak contraction.
*opposite for white* |
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Is the sarcoplasmic reticulum extensive in red/white skeletal muscle fibers?
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red - not extensive
white - extensive |
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What are the following 3 skeletal muscle surrounding tissues (investments) composed of and what do they surround?
Epimysium Perimysium Endomysium |
Epimysium - dense irregular collagenous connective tissue - around the total muscle
Peri - less dense collagenous connective tissue derived from epi - surrounds bundles/fascicles/muscle fibers Endo - of reticular fibers and an external lamina (basal lamina) - surrounds each muscle cell. |
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What is characteristic about the placement of the nuclei in skeletal muscle fibers?
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they are peripherally located, long and cylindrical. The fiber is also multinucleated.
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satellite cells
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have a single nucleus and act as a regenerative cells. Located in shallow depression on muscle cell's surface.
Has a denser and coarser chromatin network |
