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What is a sarcomere?
- The smallest contractile unit of a muscle, from z disc to z disc.
- The functional unit of a myofibril.
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What type of proteins are actin and myosin in skeletal muscle?
Contractile proteins.
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What type of proteins are troponin and tropomyosin?
Regulatory proteins.
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What is a sarcolemma?
The plasma membrane of the skeletal muscle cell.
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What ion is stored in the sarcoplasmic reticulum?
Calcium ions
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What is a fascicle?
Bundles of muscle fibers surrounded by connective tissue.
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What is the endomysium?
Connective tissue surrounding each individual muscle fiber.
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What is perimysium?
Connective tissue surrounding each fascicle.
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What is epimysium?
Connective tissue surrounding the entire muscle. Outermost.
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What type of filaments contain actin?
Thin filaments
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What type of filaments contain myosin?
Thick filaments
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Which filaments have the active sites located on them?
Actin
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What is a cross bridge?
- Formed when myosin heads link with the binding sites of actin.
- (Linking together of thick and thin filaments)
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What type of protein is titin?
Structural protein
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What ion does troponin bind to in skeletal muscle?
Calcium ions
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What is anchored in the z discs?
Actin and titin
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Where are calcium ions stored in a relaxed skeletal muscle?
- Sarcoplasmic reticulum
- (cytosol)
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What are t (transverse) tubules?
Invaginations (infoldings) of the sarcoplasm.
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What travels down the T tubules?
Action potentials.
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What is acetycholine?
The neurotransmitter used in skeletal muscle contraction.
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What type of muscle contains dense bodies?
Smooth muscle
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What is calsequestrin?
A calcium binding protein, helps store high concentrations of calcium in SR
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What type of muscle uses calmodin to bind calcium?
Smooth muscle
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What is the sliding filament mechanism?
- Power stroke/Recovery stroke
- Thin filaments slide past thick ones, overlap slightly creating contraction.
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What is a isometric contraction?
Tension builds in muscle, but it never shortens or lengthens.
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What is concentric isotonic contraction?
The muscle shortens as it does work.
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What is eccentric isotonic contraction?
The muscle generates force as it lengthens.
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What is elasticity of muscle?
The ability of muscle tissue to return to it's original length and shape.
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What is extensibility of muscle?
The ability of a muscle to stretch w/o being damaged.
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What is the neuromuscular junction?
Where nerves meet a muscle.
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What is the motor end plate?
The area of the sarcolemma containing ACh receptors.
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What is a muscle twitch?
- A motor unit's response to a single action potential of its motor neuron,
- Latent period, Period of contraction, Period of relaxation.
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What is unfused tenatus?
A sustained but quivering contraction due to increase frequency of contractions.
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What is fused tenatus?
Reach of state where there is no muscle relaxation; smooth sustained contraction.
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What muscle type has intercalated discs?
Cardiac muscle.
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What molecule is hydrolyzed to provide energy for muscle contraction?
ATP
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Where are calcium ions stored during relaxation of muscles?
- Sarcoplasmic reticulum
- (Cytosol)
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Where are calcium ions released into when muscle contractions occur?
Cytosol
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What is the creatine phosphate system?
ATP source for immediate 10-15 secs of activity. (Direct phosphorylation)
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What is the glycolysis-lactic acid (anaerobic) system?
ATP source after CP, splits glucose into pyruvic acid, 30-60 secs anaerobic.
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What is cellular respiration?
Metabolic process in which ATP is produced.
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What strength of contraction results from optimum overlap of muscle filaments?
Maximum
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What strength of contraction results from minimal overlap of muscle filaments?
Weak
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What strength of contraction results from too much overlap of muscle filaments?
Weak
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What are slow oxidative muscle fibers?
Red, good fatigue resistance, lots of myoglobin, smallest in diameter.
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What are fast glycolytic muscle fibers?
White, little ,myoglobin, fatigue quickly, large in diameter.
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