MUSCULAR SYSTEM Part 4: Muscle Movement

OBJECTIVES  Explain how the attachments, locations and interactions of skeletal muscles make possible certain movements  Identify and locate the origin and insertions of each muscle  Describe the action of each muslce

ATTACHMENT OF MUSCLES  Skeletal muscles are attached to one end of a ______, stretch across a ______, and are fastened to a point on __________________  Muscles are attached to the _________ of the bone, directly or by a tendon …A ___________ is a tough fibrous cord of connective tissue  The point where the muscle attaches to a stationary bone is called the ______________  The point where the muscle attaches to the moving bone is called the _____________

MOVEMENT  Most skeletal muscles are arranged in opposing pairs …One muscle in a pair moves a limb in one direction; the other muscle moves it in the opposite direction.  Muscles move ____________ by pulling them …For example: when the biceps muscle contracts, the elbow bends.  A __________ is a muscle that bends a joint.  An __________ is a muscle that straightens a joint.  To bring about a smooth movement, one muscle in a pair must _________while the opposing _______________

Flexors Extensors

MOVEMENT CONT.  _____________  _____________ are muscles that take away from the body …Ex. lifting the arm to the side and spreading out your fingers  Adductors are the opposites of abductors They are muscles that move __________ the body …Ex. lowering an arm raised to the side and moving your fingers together while keeping them straight

INTERACTION OF SKELETAL MUSCLES  Most skeletal muscles function in groups, thus for a particular movement you need more than the contraction of a single muscle  Three types of interactions:  __________: a muscle that causes an action …Also known as the prime mover …For example: the deltoid muscle abducting the arm  ___________: muscles near an agonist contract to help with the action …For example: the supraspinatus contracts to help the deltoid abduct the arm  ___________: muscles that work to oppose an action …For example: the same muscles that raise the upper arm can lower the upper arm

MUSCLE FATIGUE  Happens when _____________availability fails to keep pace with its use  It causes controlled muscle activity to cease, even though the muscle may still receive nerve stimulation to move  ___________________is the physiological inability of a muscle to contract  Muscle fatigue is a result of the depletion of ATP  When ATP is absent, a state of continuous contraction occurs. …Ex. Severe muscle cramps

OXYGEN DEBT  Large amounts of oxygen are needed to maintain the rate of maximum ATP production required to sustain strenuous exercise  However, after several minutes of heavy exertion, the circulatory system and the respiratory system are not able to keep up with the demands  Oxygen levels become depleted as result, which we called _________________  Oxygen debt leads to an accumulation of __________ as metabolic waste in the muscle fibers  Lactic acid produces the soreness you may experience after prolonged exercise