Myology and Muscle Classification
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Questions and Answers

What is the primary function of a muscle's origin?

  • To provide a moving point for muscle attachment
  • To serve as the most distal point of attachment
  • To connect muscles to bones via tendons
  • To remain fixed during muscle contraction (correct)

    • Which type of muscle attachment is characterized by a cord-like band of fibrous tissue?

  • Connector tissue
  • Raphae
  • Tendon (correct)
  • Aponeurosis

    • What are sesamoid bones primarily associated with?

  • Providing additional flexibility to joints
  • Serving as a leverage point for tendons (correct)
  • Protection of the muscle fibers
  • Connection between ligaments and muscles

    • What distinguishes aponeuroses from other muscle attachments?

    <p>They are thin but strong flat sheets.</p> Signup and view all the answers

    Which term describes a feature formed by the interdigitation of aponeurosis of flat muscles?

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

    What is the primary function of skeletal muscles?

    <p>Produce voluntary movements</p> Signup and view all the answers

    Which layer of connective tissue encases individual muscle fibers?

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

    Which type of muscle is characterized by striated fibers and voluntary control?

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

    What type of muscle tissue is responsible for involuntary contractions and is found in the heart?

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

    What is the function of smooth muscle within the body?

    <p>Regulate involuntary actions</p> Signup and view all the answers

    Which of the following is NOT a form of skeletal muscle?

    <p>Cardiac muscles</p> Signup and view all the answers

    What structure supports the synchronized contraction of cardiac muscle tissue?

    <p>Intercalated discs</p> Signup and view all the answers

    Which connective tissue layer is found surrounding the entire muscle?

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

    Which of the following describes a type of parallel muscle?

    <p>Rectus abdominis</p> Signup and view all the answers

    What is the primary characteristic of convergent muscles?

    <p>A broad area converges to a single attachment site</p> Signup and view all the answers

    Which type of pennate muscle has fibers on both sides of a tendon?

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

    What is the role of an antagonist muscle?

    <p>Opposes the movement of the agonist</p> Signup and view all the answers

    Which of the following best describes circular muscles?

    <p>Open and close to guard entrances of the body</p> Signup and view all the answers

    Which terms describe the functional roles within a muscle group?

    <p>Agonist, antagonist, synergist</p> Signup and view all the answers

    Which of the following correctly defines 'sarcoplasm'?

    <p>The cytoplasm within a muscle fiber</p> Signup and view all the answers

    What makes up the majority of total protein in skeletal muscle?

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

    What term describes the specific orientation of muscle fibers in a muscle?

    <p>Fascicle organization</p> Signup and view all the answers

    Which of the following describes a muscle that is primarily visible at the body surface?

    <p>Externus (superficialis)</p> Signup and view all the answers

    What is the significance of the prefix 'bi' in muscle naming?

    <p>Indicates two tendons present</p> Signup and view all the answers

    What best describes smooth muscle?

    <p>No striations and single nuclei</p> Signup and view all the answers

    Which of these names is used to describe muscles that are created based on their action?

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

    Which type of fascia is characterized by being formed of dense fibrous tissue and spreading over muscles?

    <p>Deep fascia</p> Signup and view all the answers

    What is the role of annular ligaments in relation to tendons?

    <p>Convert grooves into canals</p> Signup and view all the answers

    Which muscle type is under autonomic control?

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

    Study Notes

    Myology

    • Myology studies muscles and accessory structures like fascia, tendon sheaths, and bursae.
    • Muscles are contractile tissues made of muscle fiber bundles, responsible for movement.

    Muscle Functions

    • Movement production
    • Heat generation in warm-blooded animals
    • Body stabilization
    • Substance transport within the body

    Muscle Classification

    • Skeletal muscle: Striated, voluntary control
    • Smooth muscle: Non-striated, involuntary control
    • Cardiac muscle: Striated, involuntary control

    Skeletal Muscle

    • Striated fibers
    • Multinucleated
    • Voluntary control
    • Epimysium: Outermost connective tissue layer surrounding the muscle
    • Perimysium: Middle layer, encases fascicles (bundles of muscle fibers)
    • Endomysium: Innermost layer, surrounds individual muscle fibers

    Skeletal Muscle Forms

    • Long muscles: Found in limbs
    • Flat muscles: Found in abdomen and chest
    • Short muscles: Various locations
    • Sphincter muscles: Ring-like muscles closing orifices, examples include:
      • Sphincter ani: Around the anus
      • Orbicularis oris: Around the mouth
      • Orbicularis oculi: Around the eye

    Skeletal Muscle Attachment

    • Origin: Fixed point of attachment, usually proximal
    • Insertion: Movable point of attachment, usually distal
    • Tendon: Cord-like, fibrous tissue connecting muscle to bone
    • Aponeurosis: Thin, strong sheet of fibrous tissue, found in flat muscle attachments
    • Raphae: Interdigitation of aponeuroses, examples:
      • Pharyngeal raphe: Short aponeurosis
      • Linea alba: Wide and long aponeurosis between abdominal muscles

    Skeletal Muscle Fiber Organization

    • Parallel: Fibers parallel to the long axis of the muscle, example: biceps brachii
    • Convergent: Muscle fibers converge on a single attachment point, example: pectoralis muscles
    • Pennate: Muscle fibers are obliquely arranged, with different subtypes:
      • Unipennate: Fibers on one side of the tendon, example: extensor digitorum
      • Bipennate: Fibers on both sides of the tendon, example: rectus femoris
      • Multipennate: Series of bipennate arrangements, example: deltoid
    • Circular: Also called sphincters, guard body entrances, example: obicularis oris

    Muscle Actions

    • Movements generated by muscle contraction, classified as:
      • Flexors
      • Extensors
      • Adductors
      • Abductors
      • Cutaneous

    Muscle Terminology

    • Agonist (prime mover): Muscle responsible for the primary movement
    • Antagonist: Muscle opposing the agonist's movement
    • Synergist: Smaller muscle assisting the agonist, may help start motion or stabilize the origin
    • Fixator: Synergist muscle stabilizing the origin of the agonist

    Sarcomere

    • Basic structural and functional unit of muscle

    Contractile Proteins

    • Actin: Thin myofilament
    • Myosin: Thick filament
    • Tropomyosin: Thin filament
    • Troponin: Thin filament
    • Actin and myosin constitute approximately 55% of total protein in skeletal muscle

    Muscle Description

    • Name:
      • Action: extensor, adductor
      • Shape: quadratus, triangularis
      • Direction: rectus, oblique
      • Position: subscapularis, iliacus
      • Division: biceps, triceps
      • Size: major, minor
      • Attachment: sterno-cephalicus
      • Structure: semitendinosus
    • Shape: triangular, quadrilateral, fusiform
    • Attachment: cartilage, bone, skin
    • Action: movement produced
    • Structure: including direction and arrangement of fibers
    • Relations: relationship to surrounding structures

    Naming Skeletal Muscles

    • Location: Identifies body regions, example: temporalis muscle
    • Origin and insertion: First part of name indicates origin, second part indicates insertion, example: genioglossus muscle
    • Fascicle organization: Describes fiber orientation within the muscle, example: rectus (straight), transversus, oblique
    • Relative position: Describes muscle depth and location within the body, example: externus (superficialis), interus (profundus), extrinsic, intrinsic
    • Structural characteristics: Number of tendons, shape, size, example: bi = 2, tri = 3, trapezius, deltoid, rhomboid, major, minor
    • Action: Movement produced, example: flexor, extensor, retractor

    Muscle Fascia

    • Superficial fascia: Loose connective tissue, may contain fat, also called subcutaneous fascia
    • Deep fascia: Dense fibrous tissue, spreads over muscles, may fuse with epimysium, tendons, bones, and ligaments, forms fibrous sheaths around muscles, forms annular ligaments to create canals for tendons

    Bursa and Synovial Sheath

    • Bursa: Fluid-filled sac reducing friction between structures
    • Synovial sheath: Encloses tendons to reduce friction during movement
    • Peritendon: Outer layer of the synovial sheath
    • Mesotendon: Attaches the peritendon to tendon
    • Bone: Connective tissue with a rigid extracellular matrix
    • Periosteum: Membrane covering bone, important for growth, repair, and attachment of tendons

    Smooth Muscle

    • Non-striated
    • Spindle-shaped
    • Single nucleus
    • Autonomic control

    Cardiac Muscle

    • Striated
    • Uninucleated
    • Intercalated discs facilitate synchronized contraction
    • Autonomic control

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    Anatomy Lecture 5&6_Myology PDF

    Description

    Explore the fascinating field of myology, which focuses on muscle structure and function, including the various types of muscles and their roles in the body. This quiz covers muscle classifications, functions, and the intricacies of skeletal muscle anatomy.

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