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26 Cards in this Set
- Front
- Back
Skeletal Muscle Tissue
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Has striations
Found in skeletal muscles attached to the skeleton Controlled Voluntarily Extremely adaptable (can exert a variable amount of force) |
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Cardiac Muscle Tissue
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Striated like skeletal muscle
Occurs only in the heart Involuntary neural controls allow the heart to respond to changes in bodily needs |
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Smooth Muscle Tissue
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Doesn't have striations
Found in the walls of hollow organs Controlled by involuntary neural and hormonal mechanisms |
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Excitability
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The ability to receive and respond to stimuli
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Contractility
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The ability to shorten forcibly
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Extensibility
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The ability to be stretched or extended
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Elasticity
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The ability to recoil and resume the original resting length
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Producing movement
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Muscle produces movement of the body or of materials within the body
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Maintaining Posture
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Keep the body upright against the force of gravity
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Stabilizing Joints
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Muscle tone and tension reinforces joints
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Generating Heat
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Muscle activity generates heat, important in maintaining body temperature.
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Sarcolemma
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The cell membrane surrounding the muscle fiber
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Sarcoplasm
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The cytoplasm of muscle cell that contains large amounts of Glycogen, and Myoglobin
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Glycogen
Myoglobin |
G- Stored glucose
M- Binds and stores oxygen |
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Myofibrils
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Densely packed rodlike contractile elements.
Bundles of myofilaments The arrangement of myofilaments and myofibrils creates a repeating series of dark and light bands (striations) in a muscle fiber |
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Sarcomeres
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The smallest contractile until of muscle
The region of a Myofibril between 2 successive Z discs Composed of myofilaments or contractile proteins |
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Myofilaments
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Contractile protein filaments two types thick and thin
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Myosin (Thick)
Actin (Thin) |
Myosin- extend the entire length of an A band
Actin- extend across the I band and partway into the A band |
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A band
I band H zone |
A band- Dark band where thick filaments are found
I band- Light band btw the ends of thick filaments 2 sarcomeres H zone- Lighter area in the A band where thick and thin filaments do not overlap |
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M line
Z disc |
M line- dark line in the H zone due to the presence of the protein desmin (connects adjacent thick filaments)
Z disc- coin shaped sheet of protein (nebulin) that anchors the thin filaments and connects myofibrils to one another |
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Thick Filaments
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Composed of the protein myosin
Each myosin has a rodlike tail and two globular heads Tails- two interwoven polypeptide chains heads Heads- two smaller polypeptide chains that form cross bridges. |
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Thin Filaments
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(Actin, Tropomyosin and Troponin)
Chiefly composed of the protein actin Each actin molecule is helical polymer of gobular subunits called G actin |
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Elastic Filaments (titin)
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Composed protein
Extend from the Z disc to the thick filament Runs within the thick filament and attached to the M-line Hold the thick filaments in place; help the cell to recoil back to shape when stretched. |
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Sarcoplasmic Reticulum
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Elaborate, smooth endoplasmic reticulum that surrounds each myofibril
Paired terminal cisternae from perpendicular cross channels Functions in the regulation of intracellular calcium levels |
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T-tubules
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Elongate tubes that penetrate into the cell's interior at each A band and I band Junction
Continuous with the sarcolemma Associate with terminal cisternae to form triads Conduct impulses that signal for the regulate Ca2+ release from adjacent terminal cisternae |
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Triads
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T-tubules and terminal cisternae form triads that conduct signals for muscle contraction
T-tubule proteins act as voltage sensors SR foot proteins are receptors the regulate Ca2+ release from the SR cisternae |