[LAB] Muscular System

• What are bundles of skeletal muscle fibers called?

  Fascicles
• How are muscles classified based on fascicle arrangement?

  Muscles are classified as parallel, convergent, pennate, or circular.
• What are the types of muscle fascicle arrangements?

  • Parallel muscles
  • Convergent muscles
  • Pennate muscles
  • Circular muscles
• What is an example of a parallel muscle?

  Biceps brachii
• What is the characteristic of parallel muscles?

  Fascicles are parallel to the long axis of the muscle.
• What is the maximum shortening percentage of parallel muscles when contracting?

  About 30%
• How do convergent muscles differ from parallel muscles?


  Convergent muscles spread in a broad area and converge at an attachment site.
• What is an example of a convergent muscle?

  Pectoralis muscles
• What defines pennate muscles?

  The fascicles form a common angle with the tendon.
• What is an example of a unipennate muscle?

  Extensor digitorum
• What is an example of a bipennate muscle?

  Rectus femoris
• What is an example of a multipennate muscle?

  Deltoid
• What are circular muscles also known as?

  Sphincters
• What is the function of circular muscles?

  They surround body openings and hollow organs, acting as valves.
• What is an example of a circular muscle?

  Orbicularis oris
• What is a lever in the context of the muscular system?

  A lever is a rigid structure that moves on a fixed point called the fulcrum.
• What role do bones play in the lever system?

  Bones act as levers, while joints serve as fulcrums.
• What are the three classes of levers based on?


  They are based on the relative positions of the applied force, fulcrum, and load.
• What is an example of a first-class lever?

  Extension of the neck
• How does a second-class lever function?

  The load lies between the applied force and the fulcrum.
• What is an example of a second-class lever?

  Ankle extension (plantar flexion) by calf muscles
• What is a third-class lever?

  The applied force is between the load and the fulcrum.
• What is an example of a third-class lever?

  Elbow flexion by the biceps brachii
• What is the origin of a muscle?

  The origin is the fixed (less movable) point of attachment of a muscle to a bone.
• What is the insertion of a muscle?

  The insertion is the more movable point of attachment of a muscle to a bone.
• How is muscle action described?

  Muscle action is described in terms of the effect on the bone or the joint.
• What is an example of a specific muscle action?


  Adduction
• What are the four functional types of muscles?

  • Agonist (prime mover)
  • Antagonist
  • Synergist
  • Fixator
• How do agonists and antagonists work together?

  When one contracts, the other stretches or undergoes an eccentric contraction.
• What is the approximate number of skeletal muscles in the human body?

  Approximately 700
• What descriptive information can muscle names provide?

  • Region of the body
  • Position, direction, or fascicle arrangement
  • Structural characteristics
  • Action
• What does the term "brachial" refer to?


  Arm
• What does the term "cervicis" refer to?

  Neck
• What does the term "femoris" refer to?

  Thigh
• How does muscle organization affect movement?

  It dramatically affects the power, range, and speed of movement.
• What are bundles of skeletal muscle fibers called?

  Fascicles
• What are the classifications of muscle based on fascicle arrangement?

  • Parallel muscles
  • Convergent muscles
  • Pennate muscles
  • Circular muscles
• What is the characteristic of parallel muscles?

  Fascicles are parallel to the long axis of the muscle.
• Can entire parallel muscles shorten when contracting? If so, by how much?

  Yes, they can shorten about 30% when contracting.
• Give an example of a parallel muscle.

  Rectus abdominus