Muscular System

• 640 - the number of voluntary skeletal muscles in the human body
• Voluntary - muscles which we can control as opposed to the muscles of the heart and intestines which we cannot control
• Muscles - made of microscopic filaments which contract and slide over each other
• Three of the strongest muscles: soleus, masseter, tongue
• There are three types of muscles: skeletal, cardiac, and smooth
• Skeletal - a type of muscle that is attached to the bones of the body
• Cardiac - type of muscle that is found in the heart
• Smooth - type of muscle found in walls of hollow visceral organs
• Origin - the attachment of a muscle on the more stable bone
• Insertion - the attachment of a muscle on the more moveable bone
• Prime mover - muscle that has major responsibility for causing a particular movement
• Antagonists - muscles that oppose or reverse a movement.
• Synergists - muscles that help prime movers by producing the same movement or by reducing undesirable movements.
• Fixators - stabilizes the origin of a prime mover so that all tension can be used to move the insertion bone.
• Frontalis - thin, wide, four-sided muscle that elevates the forehead
• Orbicularis Oculi - Opens and closes the eyelids and used for squinting
• Orbicularis Oris - attachment to many facial muscles. Contributes to shape and form of lips. Used for kissing.
• Zygomaticus - pull the angle of the mouth for smiles
• Buccinator - facial expression and mastication. used for whistling.
• Masseter - Main muscle of mastication. Elevate jaw bone bringing teeth together for chewing.
• Sternocleidomastoid - neck flexion, extension, lateral rotation
• Platysma - Superficial neck muscle. Pulls down mandible, opens the mouth and pulls corners of lips out. Forms a frown.
• Deltoids - shoulder abduction
• Pectoralis Major - Largest chest muscle, fan shaped, shoulder horizontal abduction
• Rectus Abdominis - 6 pack abs. flex the lumbar spine
• Transversus Abdominis - deep muscle of the abdominal wall
• abduction - movement away from midline of body
• adduction - movement toward the midline of the body
• extension - straightening of limbs
• flexion - bending of limbs
• Orbicularis Oculi

  
• Orbicularis Oris

  
• Zygomaticus

  
• Green: Orbicularis Oris

  Yellow: Buccinator

  
• Masseter

  
• Sternocleidomastoid

  
• Platysma

  
• Deltoids

  
• Pectoralis Major

  
• Rectus Abdominis