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28 Cards in this Set
- Front
- Back
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What is a motor unit? How do they contract?
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It's the neuron and the muscles fibers, collectively.They contract asynchronously.
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What is a threshold stimulus?
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It is when the muscle contraction is first oberveable.
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What is a muscle twitch?
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It's the response to a single, brief threshold stimulus.
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What are the three phases of the simlest contraction? And what what in those phases?
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(1) Latent Period-Exictation-Contraction coupling. (2) Period of Contraction-Cross Bridge Formation;tension release. (3) Period of Relaxation- Ca2+ renenters the SR
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What affects the graded muscle response?
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The strength and frequency of the stimulus.
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What is the size principle?
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Motor units w/larger and larger fibers are recruited as stimulus intensity increases.
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What is muscle tone?
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State of slightly constant contraction.
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What are the two types of Isotonic contractions and their meanings?
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(1) Concentric-muslces shortens and does work (2) Eccentric-muscles contracts as it lengthens.
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What increases the sttrength in muscles in relation to cells?
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The Hypertrophy of the cells.
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What are the 4 factors that affect the muscle contractions?
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(1) Recruitment (2) Relative size of fibers (3) Frequency of stimulus (4) Length-Tension relationship
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What is the length-tension relationship?
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Muscles contract most strongly when muscle fibers are 80-120% of their normal resting rate.
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What influences the duration and velocity of a contraction?
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(1) muscle fiber type (2) Load (3) Recruitment
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What are two characteristics of muscle fiber type?
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(1) Speed of Contraction (2) Metabolic pathways for ATP synthesis.
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What are the three muscle fiber types?
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(1) Slow oxidative (2) Fast Oxidative (3) Fast Glyolytic
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What are the four steps of muscle contraction?
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(1) ACh is released (2) Ach binds to receptors (depolorization (3) AS depolorization occurs, AP is propagated into T-Tubules (4) SR then release the CA2+
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What is the graded muscle response?
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It's the variation of stimulation needed in Skeletal muslce contraction in order to have controlled movement.
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Which band contains the thin filaments? Which band contains the thick filaments?
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The I-Band. The H-zone.
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What are the four characteristics of muscel tissues?
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(1) Excitability (2) Contractibility (3) Extensibility (4) Elasticity
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What does each muscle have?
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1 artery 1 Nerve and one or more veins.
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What is an Axon?
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It is the extension of the somatic motor nerves.
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What happens to the ions during depolorization?
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More sodium enters and less potassium leaves.
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When is Action Potential created?
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When the threshold of NA+ flux is reached.
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What are the events in the generation of Action Potential?
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(1) Local Depolorization (2) Generation and Propagation of an action potential (3) Repolorization
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What kind of channels are opening and closing during action potential?
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NA channels. open until repolorization occurs. When repolorizataion occurs K channels open.
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When does resting membrane potential occur?
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When a resting neuron has > - charge on the inside of the membrane.
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What are the two factors that make up resting membrane potential/
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(1) Na/K gradients along membrane. (2) The differential permability of the plasma membrane.
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What changes the shape of the voltage-gated sodium channels?
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The threshold stimulus.
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What are the three phases of the Action Potential
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(1) Depolorization-membrane potential becomes less negative (2) Repolorization (3) Hyperpolorization
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