Muscle Structure and Types

• Skeletal muscle


  Muscle responsible for conscious movement, such as the biceps and triceps.
• Striated muscle


  Muscle with a striped appearance under a microscope, composed of parallel fibers.
• Voluntary muscle


  Muscle that can be consciously controlled by the individual.
• Muscle fibers


  Long cells that make up skeletal muscle, capable of contraction.
• Muscle fascicles


  Groups of long muscle cells that work together to generate force.
• Sarcolemma


  Cell membrane surrounding a muscle fiber, essential for muscle contraction.
• T tubules


  Inward folds of the sarcolemma, allowing for the transmission of electrical signals.
• Nuclei


  Multiple nuclei found within muscle fibers, responsible for protein synthesis and repair.
• Sarcoplasm


  Shared cytoplasm of muscle fibers, containing various organelles and myofibrils.
• Sarcoplasmic reticulum


  Modified endoplasmic reticulum in muscle fibers, storing and releasing calcium ions for muscle contraction.
• Mitochondria


  Organelles in muscle fibers that produce ATP, the energy source for muscle contraction.
• Myofibrils


  Long, cylindrical organelles within muscle fibers, composed of sarcomeres and responsible for muscle contraction.
• Thick filament


  Myosin protein within myofibrils, responsible for generating force during muscle contraction.
• Thin filament


  Actin protein within myofibrils, involved in muscle contraction and regulation.
• Sarcomeres


  Repeating units within myofibrils, responsible for the striated appearance of muscle fibers.
• Photomicrograph


  Image of a stained section through skeletal muscle, used for studying muscle structure.
• A bands

  Dark bands seen in photomicrographs of skeletal muscle, containing overlapping thick and thin filaments.
• I bands

  Light bands seen in photomicrographs of skeletal muscle, containing only thin filaments.
• Cardiac muscle


  Muscle found in the heart, responsible for rhythmic contractions that pump blood throughout the body.
• Smooth muscle


  Involuntary muscle found in hollow organs and blood vessels, responsible for various physiological functions.
• Intercalated disks


  Specialized connections between cardiac muscle cells, allowing for synchronized contractions of the heart.