Muscle Anatomy and Composition
29 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is responsible for the actual muscle contraction?

  • Ends of actin filaments
  • Actin and myosin filaments (correct)
  • Tendon fibers
  • Myofibrils
  • Which part of the muscle fibers contains both myosin and actin filaments?

  • Myofibrils
  • Tendon fibers
  • I bands
  • A bands (correct)
  • How many myofibrils does each muscle fiber typically contain?

  • Over 5000 myofibrils
  • 10-20 myofibrils
  • Several hundred to several thousand myofibrils (correct)
  • 50-100 myofibrils
  • Which type of filaments are found in the light bands of myofibrils?

    <p>Only actin filaments</p> Signup and view all the answers

    What causes the myofibrils to have alternate light and dark bands?

    <p>Actin and myosin filaments partially interdigitating</p> Signup and view all the answers

    Which part of the muscle fibers is isotropic to polarized light?

    <p>I bands</p> Signup and view all the answers

    What happens to the ends of actin filaments in the contracted state according to the sliding filament mechanism of muscle contraction?

    <p>They overlap one another to their maximum extent</p> Signup and view all the answers

    What is the primary cause of actin filaments sliding inward among the myosin filaments during muscle contraction?

    <p>Force generated by the interaction of cross-bridges from myosin filaments with actin filaments</p> Signup and view all the answers

    Where are the Z discs positioned in the contracted state according to the sliding filament mechanism of muscle contraction?

    <p>Pulled up to the ends of the myosin filaments by the actin filaments</p> Signup and view all the answers

    Why are the forces generated by cross-bridges from myosin filaments with actin filaments inactive under resting conditions?

    <p>The forces are not needed when muscles are at rest</p> Signup and view all the answers

    What factor determines whether the actin filaments begin to overlap one another in the relaxed state according to the sliding filament mechanism of muscle contraction?

    <p>Proximity to the Z discs</p> Signup and view all the answers

    What is the initial trigger for contraction in muscle fibers?

    <p>Presence of calcium ions</p> Signup and view all the answers

    What is the major source of energy for the contractile process in muscle fibers?

    <p>ATP molecule degradation</p> Signup and view all the answers

    How many polypeptide chains make up a myosin molecule?

    <p>Six</p> Signup and view all the answers

    Which molecular characteristic describes the structure of myosin tails?

    <p>Double helix formation</p> Signup and view all the answers

    What occurs when myosin and actin filaments interact in muscle contraction?

    <p>Cross-bridge formation</p> Signup and view all the answers

    In the sliding filament model, what is the role of calcium ions in muscle contraction?

    <p>Activation of myosin-actin forces</p> Signup and view all the answers

    What part of the myosin molecule forms the body of the filament?

    <p>Tails</p> Signup and view all the answers

    Which component of the myosin head is involved in controlling its function during muscle contraction?

    <p>Light Chains</p> Signup and view all the answers

    What is the approximate total length of each myosin filament?

    <p>1.6 micrometers</p> Signup and view all the answers

    Which part of the myosin filament extends outward to the sides?

    <p>Heads</p> Signup and view all the answers

    What is the role of the hinged heads in muscle contraction?

    <p>Participate in the actual contraction process</p> Signup and view all the answers

    Why are there no cross-bridge heads in the center of the myosin filament for a distance of about 0.2 micrometers?

    <p>Because of hinged arms extending away from the center</p> Signup and view all the answers

    What is the function of cross-bridges in muscle contraction?

    <p>Interact with actin filaments to cause contraction</p> Signup and view all the answers

    What is the role of titin molecules in muscle contraction?

    <p>Anchor myosin and actin filaments in place</p> Signup and view all the answers

    Where are the Z-discs located in relation to muscle contraction?

    <p>At the ends of actin filaments</p> Signup and view all the answers

    What is the primary function of the sarcomere in muscle physiology?

    <p>Mediate the interaction between myosin and actin filaments</p> Signup and view all the answers

    Why is titin described as a 'springy' molecule?

    <p>It changes length as the sarcomere contracts and relaxes</p> Signup and view all the answers

    Which organelle supplies contracting myofibrils with energy in the form of adenosine triphosphate (ATP)?

    <p>Mitochondria</p> Signup and view all the answers

    More Like This

    Muscle and Tendon Anatomy Quiz
    11 questions
    Golgi Tendon Organ Overview
    100 questions

    Golgi Tendon Organ Overview

    SatisfiedDivisionism avatar
    SatisfiedDivisionism
    MUSCLE,JOINTS AND TENDONS
    15 questions
    Use Quizgecko on...
    Browser
    Browser