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Muscular System. Muscular Syste m. Muscles use chemical energy to exert a pulling force Many functions Movement of body parts Propel body fluids and food Heartbeat Distribute heat Protects body. Types of Muscle. Smooth Muscle Cardiac Muscle Skeletal Muscle. Smooth Muscle.
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Muscular System • Muscles use chemical energy to exert a pulling force • Many functions • Movement of body parts • Propel body fluids and food • Heartbeat • Distribute heat • Protects body
Types of Muscle • Smooth Muscle • Cardiac Muscle • Skeletal Muscle
Smooth Muscle • Peristalsis, vasoconstriction • No Striations • Single nucleus • No Transverse Tubules • No Intercalated Discs • Involuntary • Tapered
Cardiac Muscle • Heartbeat • Striations • Single nucleus • Transverse Tubules • Intercalated Discs • Involuntary • Branched
Skeletal Muscle • Movement of bones at joints • Striations • Multiple nuclei • Transverse Tubules • No Intercalated Discs • Voluntary • Non-Branched
Levers • Skeletal muscles act as levers • Levers are simple mechanical devices consisting of a • Rod • Fulcrum • Weight (Resistance) • Force Applied
1st Class Lever • Fulcrum located between resistance and force • Ex. Extending the arm at the elbow
2nd Class Lever • Resistance located between fulcrum and force • Ex. Opening mouth at mandible
3rd Class Lever • Force located between resistance and fulcrum • Ex. Flexing arm at the elbow
Features of Muscle • Origin – The head of the muscle, usually superior, relatively immobile • Insertion – The end of the muscle, usually inferior, relatively mobile • When a muscle contracts, the insertion is moved towards the origin
Muscle Interactions • Agonist – A muscle that causes an action • Ex. Deltoid is the agonist for abduction of arm • Antagonist – A muscle that opposes an action • Ex. Pectoralis Major is the antagonist for abduction of arm • Synergist – Muscles that work together • Prime Mover – The muscle that does most of the work in synergistic relationships
Types of Movements • Flexion – Moving parts at a joint, angle decreases • Extension – Moving parts at a joint, angle increases • Hyperextension – Extension beyond anatomical position
Dorsiflexion – Moving ankle closer to shin • Plantar Flexion – Moving ankle further from shin
Abduction – Moving a body part away from the midline of the body • Adduction – Moving a body part towards the midline of the body, think ADDuction= ADDing to body
Medial Rotation – Turning a limb on its axis towards the midline of the body • Lateral Rotation – Turning a limb on its axis away from the midline of the body
Circumduction – Moving a body part so that it follows a circular path
Pronation – Rotation of forearm so that the palm is facing downward • Supination – Rotation of forearm so that the palm is facing upward, think “holds soup”
Eversion – Turning the foot so the bottom faces laterally • Inversion – Turning the foot so the bottom faces medially
Protraction – Moving a body part forward • Retraction – Moving a body part backward
Elevation – Raising a part of the body • Depression – Lowering a part of the body