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Muscular System Basics - Anatomy & Physiology

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  • What is the primary function of the muscular system?
    The muscular system enables movement of the body, maintains posture, and produces heat through muscle contractions.
  • Name the three types of muscle tissue.
    Skeletal, cardiac, and smooth muscle tissues.
  • Which muscle type is voluntary and striated?
    Skeletal muscle is voluntary and striated.
  • Where is cardiac muscle found and what is its key feature?
    Cardiac muscle is found in the heart and is involuntary and striated.
  • What distinguishes smooth muscle from other muscle types?
    Smooth muscle is involuntary, non-striated, and found in walls of internal organs.
  • What is a muscle fiber?
    A muscle fiber is a single muscle cell, long and cylindrical, containing many nuclei.
  • What is the role of myofibrils in muscle fibers?
    Myofibrils are contractile elements within muscle fibers composed of actin and myosin filaments.
  • Define the sarcomere.
    The sarcomere is the basic contractile unit of a muscle fiber, defined by Z lines.
  • What proteins are responsible for muscle contraction?
    Actin (thin filaments) and myosin (thick filaments) interact to cause contraction.
  • Explain the sliding filament theory.
    Muscle contraction occurs when actin filaments slide over myosin filaments, shortening the sarcomere.
  • What ion triggers muscle contraction?
    Calcium ions (Ca2+) released from the sarcoplasmic reticulum trigger contraction.
  • What is the role of ATP in muscle contraction?
    ATP provides energy for myosin heads to detach and reattach to actin during contraction cycles.
  • What is a motor unit?
    A motor unit consists of a motor neuron and all the muscle fibers it innervates.
  • How does muscle tone benefit the body?
    Muscle tone maintains partial contraction for posture and readiness to act.
  • What is the difference between isotonic and isometric contractions?
    Isotonic contractions change muscle length; isometric contractions generate force without changing length.
  • Name the connective tissue layers surrounding muscle components.
    Endomysium surrounds fibers, perimysium surrounds fascicles, and epimysium surrounds the whole muscle.
  • What is the function of tendons?
    Tendons connect muscle to bone and transmit force to produce movement.
  • How do muscles produce heat?
    Muscle contractions generate heat as a byproduct, helping maintain body temperature.
  • What is muscle fatigue?
    Muscle fatigue is the inability to contract due to depletion of energy or accumulation of waste products.
  • Describe the role of the neuromuscular junction.
    The neuromuscular junction is where a motor neuron communicates with a muscle fiber to trigger contraction.