Questions and Answers
What is the length-tension relationship?
What is weak contraction?
Overly contracted at rest or too stretched before stimulation.
What is muscle tone?
Central nervous system maintains the length of the resting muscle in a state of partial contraction.
What is the threshold?
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Define twitch.
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What happens during the latent period?
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What occurs during the contraction phase?
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Describe the relaxation phase.
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What is meant by increase stimulus intensity?
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What does it mean to increase stimulus frequency?
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Define motor unit.
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What is the average motor unit size?
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Describe a small motor unit.
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What characterizes a large motor unit?
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What is summation?
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Study Notes
Length-Tension Relationship
- Muscle tension and contraction force depend on initial muscle length—overly stretched or contracted affects strength.
Weak Contraction
- Muscle can be too contracted at rest, leading to reduced force generation.
- Muscle may also be too stretched before activation, resulting in weak contractions.
Muscle Tone
- Maintained by the central nervous system, keeping muscles in partial contraction at rest for readiness.
Threshold
- The minimum voltage required to trigger an action potential and initiate muscle contraction.
Twitch
- Characterized by a quick cycle involving contraction followed by relaxation.
Latent Period
- A brief delay of approximately 2 milliseconds between stimulus onset and twitch response.
Contraction Phase
- During this phase, myofilaments slide, allowing the muscle to shorten and generate force.
Relaxation Phase
- The sarcoplasmic reticulum (SR) reabsorbs calcium, leading to the release of thin filaments and a reduction in tension.
Increase Stimulus Intensity
- Increasing the voltage can enhance the strength of muscle contractions.
Increase Stimulus Frequency
- Keeping voltage constant while increasing the number of stimuli leads to a stronger muscle response.
Motor Unit
- Defined as a single motor neuron and all muscle fibers it innervates, working together for coordinated movement.
Average Motor Unit
- Typically consists of around 200 muscle fibers, striking a balance between strength and control.
Small Motor Unit
- Comprises 3-6 muscle fibers per neuron, allowing for fine control, seen in muscles like those involved in eye and hand movements.
Large Motor Unit
- Contains many muscle fibers, prioritizing strength over precision, exemplified by muscles such as the gastrocnemius.
Summation
- Refers to the recruitment of additional motor units to increase overall muscle force during contraction.
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Description
This quiz provides detailed flashcards about the length-tension relationship in muscles. Learn key terms and concepts related to muscle contraction and their definitions. Perfect for students studying physiology or muscle dynamics.
