BIG IDEA 5: Muscular System (MUS)

5.8 MUS-7 Nomenclature of skeletal muscles with location, general attachments, and actions of the major skeletal muscles

Explain and give examples of how the name of a muscle can help identify its action, appearance, or location.
1. Criteria used to name skeletal muscles include location, shape, size, direction of muscle fibers, number of origins, location of attachments, or action. The common arrangement of the fascicles varies, resulting in muscles with different shapes and functional capabilities. A muscle name often incorporates more than one of these criteria.

5.9. MUS-8 Identify the location, general attachments, and actions of the major skeletal muscles.

Describe and identify similar actions (functional groupings) of muscles in a particular compartment (e.g., anterior arm) or region (e.g., deep back), using their origin and insertion.
1. The muscles can be identified by origin, insertion, action, and nerve association.

Define and give examples of the terms prime mover (agonist), antagonist, synergist, and fixator.
1. Muscles only pull; they never push, and as a muscle shortens, the insertion is pulled toward the origin. The muscle that provides the major force for the specific movement is called the prime mover or the agonist. Muscles that oppose or reverse a particular movement are called the antagonists, and are usually located on the opposite side of the joint from the agonist. Synergists help the prime movers by adding extra force to the same movement, or by reducing undesirable or unnecessary movements. When synergists immobilize a bone to provide stability for the action of a prime
  mover, they are acting as fixators.

Compare and contrast the classes of levers in terms of the relative position of fulcrum, effort, and load, and describe examples of each in the human body (comparisons may include relative power and range of motion).
1. A lever is a rigid bar that moves on a fixed point, or fulcrum, when a force is applied to it.The applied force, or effort, is used to move a resistance, or load. In the body, the joints act as the fulcrums, the bones as the levers, and the muscle
  contraction as the effort.
2. If the load is close to the fulcrum and the effort is applied far from the fulcrum, the lever is a power lever and relatively little effort applied over a large distance is
  required to move a large load a short distance. If the load is far from the fulcrum and the effort is applied near the fulcrum, the lever is a speed lever and allows a load to be moved rapidly over a large distance. There are three types of levers: first-class, second-class, and third-class.