1. Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slides 6.1 – 6.17 Seventh Edition Elaine N. Marieb Chapter 6 The Muscular System Lecture Slides in PowerPoint by Jerry L. Cook

2. The Muscular System Slide 6.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscles are responsible for all types of body movement  Three basic muscle types are found in the body  Skeletal muscle  Cardiac muscle  Smooth muscle

3. Characteristics of Muscles Slide 6.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscle cells are elongated (muscle cell = muscle fiber)  Contraction of muscles is due to the movement of microfilaments  All muscles share some terminology  Prefix myo refers to muscle  Prefix mys refers to muscle  Prefix sarco refers to flesh

4. Skeletal Muscle Characteristics Slide 6.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most are attached by tendons to bones  Cells are multinucleate  Striated – have visible banding  Voluntary – subject to conscious control  Cells are surrounded and bundled by connective tissue

5. Connective Tissue Wrappings of Skeletal Muscle Slide 6.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Endomysium – around single muscle fiber  Perimysium – around a fascicle (bundle) of fibers Figure 6.1

6. Connective Tissue Wrappings of Skeletal Muscle Slide 6.4b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Epimysium – covers the entire skeletal muscle  Fascia – on the outside of the epimysium Figure 6.1

7. Skeletal Muscle Attachments Slide 6.5 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Epimysium blends into a connective tissue attachment  Tendon – cord-like structure  Aponeuroses – sheet-like structure  Sites of muscle attachment  Bones  Cartilages  Connective tissue coverings

8. Cardiac Muscle Characteristics Slide 6.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Has striations  Usually has a single nucleus  Joined to another muscle cell at an intercalated disc  Involuntary  Found only in the heart Figure 6.2b

9. Function of Muscles Slide 6.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produce movement  Maintain posture  Stabilize joints  Generate heat

10. Microscopic Anatomy of Skeletal Muscle Slide 6.9a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Cells are multinucleate  Nuclei are just beneath the sarcolemma Figure 6.3a

11. Microscopic Anatomy of Skeletal Muscle Slide 6.9b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sarcolemma – specialized plasma membrane  Sarcoplasmic reticulum – specialized smooth endoplasmic reticulum Figure 6.3a

12. Microscopic Anatomy of Skeletal Muscle Slide 6.10a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Myofibril  Bundles of myofilaments  Myofibrils are aligned to give distrinct bands  I band = light band  A band = dark band Figure 6.3b

13. Microscopic Anatomy of Skeletal Muscle Slide 6.10b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sarcomere  Contractile unit of a muscle fiber Figure 6.3b

14. Microscopic Anatomy of Skeletal Muscle Slide 6.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Organization of the sarcomere  Thick filaments = myosin filaments  Composed of the protein myosin  Has ATPase enzymes Figure 6.3c

15. Microscopic Anatomy of Skeletal Muscle Slide 6.11b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Organization of the sarcomere  Thin filaments = actin filaments  Composed of the protein actin Figure 6.3c

16. Microscopic Anatomy of Skeletal Muscle Slide 6.12a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Myosin filaments have heads (extensions, or cross bridges)  Myosin and actin overlap somewhat Figure 6.3d

17. Properties of Skeletal Muscle Activity Slide 6.13 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Irritability – ability to receive and respond to a stimulus  Contractability – ability to shorten when an adequate stimulus is received

18. Nerve Stimulus to Muscles Slide 6.14 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Skeletal muscles must be stimulated by a nerve to contract  Motor unit  One neuron  Muscle cells stimulated by that neuron Figure 6.4a

19. Nerve Stimulus to Muscles Slide 6.15a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Neuromuscular junctions – association site of nerve and muscle Figure 6.5b

20. Nerve Stimulus to Muscles Slide 6.15b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Synaptic cleft – gap between nerve and muscle  Nerve and muscle do not make contact  Area between nerve and muscle is filled with interstitial fluid Figure 6.5b

21. Transmission of Nerve Impulse to Muscle Slide 6.16a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Neurotransmitter – chemical released by nerve upon arrival of nerve impulse  The neurotransmitter for skeletal muscle is acetylcholine  Neurotransmitter attaches to receptors on the sarcolemma  Sarcolemma becomes permeable to sodium (Na + )

22. Transmission of Nerve Impulse to Muscle Slide 6.16b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Sodium rushing into the cell generates an action potential  Once started, muscle contraction cannot be stopped

23. The Sliding Filament Theory of Muscle Contraction Slide 6.17a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Activation by nerve causes myosin heads (crossbridges) to attach to binding sites on the thin filament  Myosin heads then bind to the next site of the thin filament Figure 6.7

24. The Sliding Filament Theory of Muscle Contraction Slide 6.17b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  This continued action causes a sliding of the actin along the myosin  The result is that the muscle is shortened (contracted) Figure 6.7

25. The Sliding Filament Theory Slide 6.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.8

26. Contraction of a Skeletal Muscle Slide 6.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscle fiber contraction is “all or none”  Within a skeletal muscle, not all fibers may be stimulated during the same interval  Different combinations of muscle fiber contractions may give differing responses  Graded responses – different degrees of skeletal muscle shortening

27. Muscle Response to Strong Stimuli Slide 6.22 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscle force depends upon the number of fibers stimulated  More fibers contracting results in greater muscle tension  Muscles can continue to contract unless they run out of energy

28. Muscle Fatigue and Oxygen Debt Slide 6.27 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  When a muscle is fatigued, it is unable to contract  The common reason for muscle fatigue is oxygen debt  Oxygen must be “repaid” to tissue to remove oxygen debt  Oxygen is required to get rid of accumulated lactic acid  Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less

29. Types of Muscle Contractions Slide 6.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Isotonic contractions  Myofilaments are able to slide past each other during contractions  The muscle shortens  Isometric contractions  Tension in the muscles increases  The muscle is unable to shorten

30. Muscle Tone Slide 6.29 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Some fibers are contracted even in a relaxed muscle  Different fibers contract at different times to provide muscle tone  The process of stimulating various fibers is under involuntary control

31. Muscles and Body Movements Slide 6.30a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Movement is attained due to a muscle moving an attached bone Figure 6.12

32. Muscles and Body Movements Slide 6.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscles are attached to at least two points  Origin – attachment to an immoveable bone  Insertion – attachment to a movable bone Figure 6.12

33. Effects of Exercise on Muscle Slide 6.31 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Results of increased muscle use  Increase in muscle size  Increase in muscle strength  Increase in muscle efficiency  Muscle becomes more fatigue resistant

34. 1.All Muscles cross at least one joint. 2.Typically, the bulk of the muscle lies proximal to the joint crossed. 3.All muscles have at least two attachments: the origin and the insertion. 4.Muscles can only pull; they never push. 5.During contraction, the muscle insertion moves toward the origin. The 5 Golden Rules of Skeletal Muscle Activity

35. Types of Ordinary Body Movements Slide 6.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Flexion  Extension  Rotation  Circumduction  Abduction  Adduction

36. Body Movements Slide 6.33 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.13

37. Special Movements Slide 6.34 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Dorsiflexion  Plantar flexion  Inversion  Eversion  Supination  Pronation  Opposition

38. Types of Muscles Slide 6.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Prime mover – muscle with the major responsibility for a certain movement  Antagonist – muscle that opposes or reverses a prime mover  Synergist – muscle that aids a prime mover in a movement and helps prevent rotation  Fixator – stabilizes the origin of a prime mover

39. Naming of Skeletal Muscles Slide 6.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Direction of muscle fibers  Oblique - diagonal  Rectus – straight  Sphincter – circling an open  Transverse – right angle to the midline

40.  Relative size of the muscle  Brevis – short  Longus – long  Maximus – largest  Magnus - large  Medius – moderately sized  Minimus - small

41.  Location of the muscle Many muscles are named for bones or regions Brachialis – arm Frontalis – frontal (bone) Femorius – femur Gluteus – posterior of hip / thigh

42.  Location of the muscle (con’t) Oculi - eye Radialis – radius Temporalis – temporal (bone) Ulnaris - ulna

43. Naming of Skeletal Muscles Slide 6.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Number of origins or muscles  Biceps - two origins  Triceps – three origins  Quadriceps – four origins

44. Naming of Skeletal Muscles Slide 6.37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location of the muscles origin and insertion Sternocleidomastoid  Sterno - on the sternum  Cleido - clavicle  Mastoid - mastoid process of the temporal bone

45.  Shape of the muscle  Deltoid - triangular  Orbicularis - circular  Platy - flattened; platelike  Quadratus - square  Rhomboideus - diamond-shaped  Trapezius - trapezoidal  Triangularis - triangular Naming of Skeletal Muscles

46.  Action of the muscle  Abductor - abducts a part  Adductor - adducts a part  Depressor – depresses a part Naming of Skeletal Muscles

47.  Action of the muscle  Extensor - extends a part  Flexor - flexes a part  Levator - elevates a part  Rotator - rotates a part Naming of Skeletal Muscles

48. Head and Neck Muscles Slide 6.38 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.14

49. Trunk Muscles Slide 6.39 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.15

50. Deep Trunk and Arm Muscles Slide 6.40 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.16

51. Muscles of the Pelvis, Hip, and Thigh Slide 6.41 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.18c

52. Muscles of the Lower Leg Slide 6.42 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.19

53. Superficial Muscles: Anterior Slide 6.43 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.20

54. Superficial Muscles: Posterior Slide 6.44 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 6.21