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Anatomy & Physiology: Muscular System Chapters 9 & 10

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이 집합의 용어 (21)

  • Three types of muscle tissue

    Skeletal: voluntary, attached to bones.
    Cardiac: involuntary, heart only.
    Smooth: involuntary, in organs and vessels.

  • Four characteristics of muscle tissue

    Excitability: responds to stimulation.
    Contractility: ability to shorten.
    Extensibility: ability to stretch.
    Elasticity: returns to original shape.

  • Functions of muscles

    Produce movement, maintain posture, stabilize joints, produce heat, support soft tissues.

  • Connective tissue coverings of muscles

    Epimysium: surrounds entire muscle.
    Perimysium: surrounds fascicles.
    Endomysium: surrounds individual muscle fibers.
    Tendon: connects muscle to bone.

  • Muscle fiber structures

    Muscle fiber = muscle cell.
    Sarcolemma = cell membrane.
    Sarcoplasm = cytoplasm.
    Myofibrils = inside fibers.
    Sarcomere = functional unit.
    Myofilaments = actin and myosin.

  • Actin vs Myosin

    Actin: thin filament.
    Myosin: thick filament.
    Sarcomere is the contractile unit.

  • Parts of a sarcomere

    Z disc: sarcomere boundary.
    A band: length of thick filaments.
    I band: thin filaments only.
    H zone: thick filaments only.
    M line: center of sarcomere.

  • Sliding filament theory steps

    Calcium released → binds troponin → tropomyosin moves → myosin binds actin → myosin pulls actin → sarcomere shortens → muscle contracts.

  • Neuromuscular junction (NMJ)

    Motor neuron communicates with muscle fiber.
    Releases acetylcholine (ACh).
    Acetylcholinesterase breaks down ACh.

  • Role of ATP and calcium in muscle contraction

    ATP provides energy.
    Calcium enables actin-myosin interaction.
    ATP allows myosin to detach from actin.

  • Types of muscle contractions

    Isometric: tension without length change.
    Isotonic: muscle changes length.
    Isotonic types: concentric (shortens), eccentric (lengthens).

  • Muscle terminology: origin vs insertion

    Origin: less movable attachment.
    Insertion: more movable attachment.

  • Muscle terminology: agonist, antagonist, synergist, fixator

    Agonist: prime mover.
    Antagonist: opposes movement.
    Synergist: assists prime mover.
    Fixator: stabilizes joint.

  • Example of agonist and antagonist in elbow movement

    Biceps brachii is agonist (flexes elbow).
    Triceps brachii is antagonist (extends elbow).

  • Common muscle movements

    Flexion: decreases joint angle.
    Extension: increases joint angle.
    Abduction: moves away from midline.
    Adduction: moves toward midline.
    Rotation: turns around axis.

  • Additional muscle movements

    Hyperextension: extends beyond anatomical position.
    Circumduction: circular movement.
    Dorsiflexion: toes move upward.
    Plantar flexion: toes point downward.
    Supination: palm faces upward.
    Pronation: palm faces downward.

  • Muscle naming criteria

    Location, shape, size, direction, number of origins, action.

  • Major anterior muscles and functions

    Frontalis: raises eyebrows.
    Orbicularis oculi: closes eyes.
    Masseter: closes jaw.
    Sternocleidomastoid: turns head.
    Deltoid: raises arm.
    Biceps brachii: flexes elbow.
    Rectus abdominis: flexes trunk.

  • Major posterior muscles and functions

    Trapezius: moves shoulder blades.
    Latissimus dorsi: extends/adducts arm.
    Triceps brachii: extends elbow.
    Gluteus maximus: extends hip.
    Biceps femoris: flexes knee.
    Gastrocnemius: plantar flexes foot.

  • Important muscle groups

    Quadriceps: front thigh, extends knee.
    Hamstrings: back thigh, flex knee.
    Abdominals: stabilize trunk.
    Rotator cuff: stabilize shoulder.

  • Four rotator cuff muscles (SITS)

    Supraspinatus, Infraspinatus, Teres minor, Subscapularis.
    Main function: stabilize shoulder joint.