Muscle Physiology Chapter 5
24 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 characterizes the function of the sarcoplasmic reticulum in muscle fibers?

  • Action potential generation
  • Movement of myofilaments
  • Ca 2+ storage (correct)
  • Protein synthesis
  • Which component of a skeletal muscle fiber conducts action potentials to the sarcoplasmic reticulum?

  • T-tubule (correct)
  • Myofilaments
  • Myofibrils
  • Sarcoplasmic reticulum
  • What is the primary protein that makes up thick myofilaments in skeletal muscle?

  • Myosin (correct)
  • Actin
  • Tropomyosin
  • Troponin
  • What is the structure of a myosin molecule composed of?

    <p>Head, tail, and hinge</p> Signup and view all the answers

    Which of the following is NOT a protein found in thin myofilaments?

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

    How are the different types of muscle tissue primarily classified?

    <p>By histological structure and control of action</p> Signup and view all the answers

    What is the name of the membrane that surrounds muscle fibers?

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

    What distinguishes skeletal muscle from other muscle types?

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

    What is the role of the acetylcholinesterase enzyme in muscle contraction?

    <p>It prevents prolonged effects of ACh.</p> Signup and view all the answers

    Which ion influx is primarily responsible for depolarizing the sarcolemma?

    <p>Na+</p> Signup and view all the answers

    What occurs immediately after calcium binds to troponin C (Tn.C)?

    <p>Myosin binding sites on actin become uncovered.</p> Signup and view all the answers

    What triggers the contraction of skeletal muscle fibers?

    <p>Release of calcium from the sarcoplasmic reticulum.</p> Signup and view all the answers

    Which type of muscle tissue is characterized as involuntary and non-striated?

    <p>Smooth muscle</p> Signup and view all the answers

    What happens to the myosin head during muscle contraction?

    <p>It cleaves ATP and bends.</p> Signup and view all the answers

    What is the function of T-tubules in muscle contraction?

    <p>They conduct action potentials to the sarcoplasmic reticulum.</p> Signup and view all the answers

    In which systems is smooth muscle predominantly found?

    <p>Cardiovascular and urinary systems.</p> Signup and view all the answers

    What is the role of tropomyosin in muscle contraction?

    <p>It inhibits the binding of myosin to actin in the relaxed state.</p> Signup and view all the answers

    Which subunit of troponin inhibits contraction?

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

    What initiates the release of acetylcholine at the neuromuscular junction?

    <p>The opening of voltage-gated calcium channels.</p> Signup and view all the answers

    In the process of excitation-contraction coupling, what is the second step?

    <p>Contraction of the muscle fiber.</p> Signup and view all the answers

    What is the primary neurotransmitter involved in communication between the nerve and muscle at the neuromuscular junction?

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

    What happens when calcium ions bind to troponin C during muscle contraction?

    <p>Tropomyosin moves away from the myosin binding site.</p> Signup and view all the answers

    Where is the motor end plate located within the muscle fiber?

    <p>Near the midpoint of the muscle fiber.</p> Signup and view all the answers

    What is one of the main components of the neuromuscular junction?

    <p>The motor end plate featuring acetylcholine receptors.</p> Signup and view all the answers

    Study Notes

    Types of Muscle Tissue

    • Muscles are classified based on their location, histological structure, and control mechanism.

    Skeletal Muscle

    • Composed of striated muscle fibers that contain myofibrils and myofilaments.
    • Myofibrils consist of thick and thin filaments; thick filaments contain myosin, while thin filaments are made of actin.
    • Each muscle fiber is encased in a cell membrane known as the sarcolemma, which conducts action potentials.
    • The sarcoplasmic reticulum (sER) stores calcium ions (Ca²⁺).
    • T-tubules conduct action potentials from the sarcolemma to the sarcoplasmic reticulum.

    Myofilaments Structure

    • Thick myofilaments are primarily composed of myosin, featuring a head, tail, and flexible hinge (neck).
    • The myosin head has an actin-binding site and an ATP-binding site essential for muscle contraction.
    • Thin myofilaments include three proteins: actin, tropomyosin, and troponin.
      • Each actin protein has a binding site for myosin.
      • Tropomyosin wraps around actin and blocks myosin-binding sites during relaxation.
      • Troponin, a multi-subunit protein, regulates contraction by binding Ca²⁺.

    Excitation-Contraction Coupling

    • Muscle contraction involves two main steps: excitation and contraction.
    • The neuromuscular junction is where the nervous system communicates with muscle fibers.
    • Nerve endings at the neuromuscular junction release acetylcholine (ACh) in response to action potentials.
    • ACh diffuses across the synaptic cleft and binds to receptors on the sarcolemma, triggering muscle fiber depolarization.

    Excitation Steps

    • Depolarization occurs when Na⁺ enters the muscle fiber, leading to action potential propagation along the sarcolemma and T-tubules.
    • This triggers the release of Ca²⁺ from the sarcoplasmic reticulum.

    Contraction Steps

    • Ca²⁺ binds to troponin C, exposing binding sites on actin for myosin.
    • Myosin heads, energized by cleaving ATP, attach to actin, initiating muscle contraction.
    • The binding of a new ATP molecule leads to detachment of myosin from actin, resulting in muscle relaxation.

    Smooth Muscle

    • Characterized as involuntary and non-striated muscle tissue.
    • Found in various systems:
      • Cardiovascular: located in blood vessels.
      • Digestive: forms sphincters in the alimentary canal.
      • Respiratory: regulates airway diameter.
      • Urinary: forms sphincters for the urinary bladder.
      • Reproductive: comprises the male reproductive tract.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Chap-5-Muscle phy.pptx

    Description

    Explore the intricacies of muscle physiology in Chapter 5. This quiz covers the different types of muscle tissues, including their histological structure and control mechanisms. Test your understanding of skeletal, smooth, and cardiac muscles.

    More Like This

    Muscle Tissue Structure and Function
    10 questions
    Anatomy and Physiology Chapter 9
    97 questions

    Anatomy and Physiology Chapter 9

    BenevolentDramaticIrony avatar
    BenevolentDramaticIrony
    FISIOPATO B2 S2 DUR
    33 questions

    FISIOPATO B2 S2 DUR

    DextrousSanJose avatar
    DextrousSanJose
    Use Quizgecko on...
    Browser
    Browser