Muscular Tissue Characteristics
22 Questions
0 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 the origin of muscular tissue in the body?

  • Mixed origin
  • Mesodermal origin (correct)
  • Ectodermal origin
  • Endodermal origin
  • What is the name of the cell membrane of a myofiber?

  • Myofibril
  • Sarcoplasm
  • Sarcolemma (correct)
  • Myosin
  • What is the function of the sarcoplasm?

  • To conduct muscle contraction
  • To store cell organoids (correct)
  • To regulate muscle relaxation
  • To contain the myofiber
  • What is the name of the structure that surrounds a muscle fiber?

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

    What is the classification of muscular tissue based on?

    <p>Structure and function</p> Signup and view all the answers

    What is the shape of skeletal muscle fibers when viewed under a light microscope?

    <p>Long and cylindrical</p> Signup and view all the answers

    What is the name of the structural and functional unit of the muscle fiber?

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

    What is the name of the system formed by a transverse tubule and two terminal cisternae of sarcoplasmic reticulum?

    <p>T-Tubular System</p> Signup and view all the answers

    Where are gap junctions found in the cardiac muscle?

    <p>At intercalated discs</p> Signup and view all the answers

    What is the main function of Purkinje fibers?

    <p>Conduction of nerve impulses</p> Signup and view all the answers

    What happens to cardiac muscle fibers when they die?

    <p>They are replaced by fibrous connective tissue</p> Signup and view all the answers

    What is the characteristic shape of smooth muscle fibers?

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

    How do smooth muscle fibers contract?

    <p>By translocation of actin and myosin filaments after cleavage of ATP</p> Signup and view all the answers

    What is the origin of new smooth muscle fibers?

    <p>From pericyte cells</p> Signup and view all the answers

    What is the function of the T-tubular system in skeletal muscle?

    <p>To conduct the wave of depolarization to the myofibrils</p> Signup and view all the answers

    Which type of skeletal muscle fibers are highly vascular and can sustain contraction for a long time without fatigue?

    <p>Type I fibers (Red fibers)</p> Signup and view all the answers

    What is the source of energy for Type I fibers?

    <p>Oxidation of fatty acids</p> Signup and view all the answers

    What is the characteristic of the muscle fiber in cardiac muscle?

    <p>It is short, cylindrical, and branched</p> Signup and view all the answers

    What is the function of the motor nerve supply in skeletal muscle?

    <p>To transmit signals from the central nervous system to the muscle fibers</p> Signup and view all the answers

    Which type of muscle fibers predominate in skeletal muscles?

    <p>Type II fibers (White fibers)</p> Signup and view all the answers

    What is the characteristic of the sarcoplasm in cardiac muscle fibers?

    <p>It has all cell organoids and inclusions</p> Signup and view all the answers

    What is the location of the T-tubular system in cardiac muscle fibers?

    <p>At the Z-lines</p> Signup and view all the answers

    Study Notes

    Muscular Tissue

    • Muscular tissue is one of the basic tissues of the body, originating from mesoderm.
    • A muscle cell, also called a myofiber, is elongated and has a cell membrane called sarcolemma and cytoplasm called sarcoplasm.
    • Sarcoplasm contains all cell organoids (mainly actin and myosin micro-filaments) and inclusions (mainly fat and glycogen).

    Structure of Muscle Fiber

    • Muscle fibers are surrounded by a connective tissue sheath called endomysium.
    • Groups of muscle fibers are called muscle bundles, surrounded by perimysium.
    • The whole muscle is surrounded by epimysium.

    Types of Muscular Tissue

    • There are three types of muscular tissue: Skeletal muscle, Cardiac muscle, and Smooth muscle.

    Skeletal Muscle

    • Sites: attached to skeleton, diaphragm, tongue, eye, and upper third of esophagus.
    • Characteristics: long, cylindrical shape with multiple peripheral flattened nuclei.
    • Functional unit: sarcomere, formed of actin and myosin filaments.
    • During muscular contraction, actin filaments slide over myosin filaments, resulting in shortening of the sarcomere.
    • Myofibrils show alternation of dark (A-band) and light (I-band) areas.
    • T-tubular system: regulates calcium ion concentration and conducts wave of depolarization to myofibrils.
    • Nerve supply: motor nerve supply (motor-end plate) and sensory supply (muscle spindle).
    • Muscle fibers can regenerate by activating new myoblasts cells called satellites.

    Types of Skeletal Muscle Fibers

    • Type I fibers (Red fibers): small diameter, high mitochondria and myoglobin content, slow contraction, sustainable for long time without fatigue, energy derived from fatty acid oxidation.
    • Type II fibers (White fibers): large diameter, low mitochondria and myoglobin content, fast contraction, easily fatigued, energy derived from glycolysis.
    • Type III fibers (Intermediate fibers): intermediate characteristics between Type I and Type II fibers.

    Cardiac Muscle

    • Sites: forms the wall of the heart (myocardium).
    • Characteristics: short, cylindrical, branched, and joined at intercalated discs.
    • Single rounded central nucleus, sarcoplasm with all cell organoids and inclusions.
    • Cross striations of dark and light bands, similar to skeletal muscles.
    • T-tubular system: formed of two tubules, lies at the Z-lines.
    • Gap junctions: allow ions and electrical impulses to pass between cardiac muscle fibers.
    • Purkinje fibers: modified cardiac muscle fibers responsible for conduction of nerve impulses.
    • Muscle fibers, when died, never regenerate but are replaced by fibrous connective tissue.

    Smooth Muscle

    • Sites: wall of gastro-intestinal tract, respiratory system, urinary system, media of blood vessel wall, and capsule of spleen, lymph node, and digestive glands.
    • Characteristics: spindle-shaped, central oval nucleus, acidophilic sarcoplasm.
    • Sarcoplasm contains all cell organoids, inclusions, and long actin with few short myosin microfilaments.
    • Cells are joined together with gap junctions, allowing electrical impulses to pass.
    • Cells can regenerate from pericyte cells around blood vessels.
    • Contraction occurs by translocation of actin and myosin filaments after ATP cleavage.

    Studying That Suits You

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

    Quiz Team

    Description

    Learn about the basic characteristics of muscular tissue, including its origin, cell structure, and components. Understand the role of myofibers, sarcolemma, and sarcoplasm in muscle function.

    More Like This

    Use Quizgecko on...
    Browser
    Browser