ANATOMY AND PHYSIOLOGY:   SKELETAL MUSCLE AND MOVEMENT

I   Muscle

            A.  Characteristics

                        1.  excitability

                        2.  contractility

            B.  Types

                        1.  cardiac

                        2.  smooth

                        3.  skeletal

II   Skeletal muscle fibers (cells)

            A.  Excitability

                        1.  neuromuscular junction

                                    a.  axon terminal

                                    b.  acetylcholine (ACh)    

                                    c.  motor end plate                           

                        2.  muscle atrophy

            B.  Contractility

                        1.  structure

                                    a.  muscle fiber appearance

                                                1.  sarcolemma

                                                2.  multinucleate

                                                3.  striated

                                    b.  internal structures

                                                1.  myofibrils

                                                2.  sarcomere

                                                3.  myofilaments

                                                            a.  myosin, thick

                                                            b.  actin, thin

                        2.  Sliding Filament Theory of Contraction

III   Skeletal Muscle (organ)

            A.  Muscle fiber organization

                        1.  muscle fibers ---> fascicles ---> whole muscle

            B.  Connective tissue organization

                        1.  endomysium

                                    a.  blood vessels and nerves

                        2.  perimysium

                        3.  epimysium

                        4.  tendon

            C.  Contraction of whole muscle

                        1.  “all or none” principle

                        2.  strength of contraction

                                    a.  number of fibers

                        3.  fatigue

                        4.  muscle tone

IV  Movement

            A.  Requirements

            B.  Muscle attachments

                        1.  origin

                        2.  insertion

            C.  Muscle roles

                        1.  agonist

                        2.  antagonist

                        3.  synergist

            D.  Rotator Cuff

V  Exercise

            A.  aerobic

                        1.  increased endurance

            B.  resistance or isometric (vs. isotonic)

                        1.  increased muscle size

                                    a.  cause of increased size 

When you finish this unit, you should be able to: 

        - compare the structure and function of the three types of muscle tissue

            -  explain the basic characteristics of all muscle tissue

            -  draw the structure of a skeletal muscle fiber including myofibril, sarcomere, myofilament, actin, myosin

            -  explain HOW a single muscle fiber shortens

            - describe the structure of a whole skeletal muscle (the organ) including the connective tissue wrappings

            - explain the “all or none” principle for a contracting muscle

            - explain how one muscle can perform different strengths of contraction

            - list the causes of muscle fatigue

            - describe what is happening inside a muscle when it is “toned”

            - describe the roles (agonist, antagonist, synergist) of muscles

            - give an example of one muscle which can perform different roles

-  use the rotator cuff muscles to demonstrate the relationship between a muscle origin, insertion, and action

            - compare aerobic exercise and isometric contraction

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