1. Essentials of Human Anatomy & Physiology Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter The System

3. The Muscular System Slide 6.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscles are responsible for all types of body movement – they contract or and are the machine of the body  Three basic muscle types are found in the body  S muscle  C muscle  S muscle

4. 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  Prefix mys refers to  Prefix sarco refers to

5. Skeletal Muscle Characteristics Slide 6.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Most are attached by tendons to bones  Cells are  – have visible banding  – subject to conscious control  Cells are surrounded and bundled by connective tissue = great force, but tires

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

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

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

9. Smooth Muscle Characteristics Slide 6.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Has no  Spindle-shaped cells  Single  Involuntary – no  Found mainly in the walls of hollow  Slow, sustained and Figure 6.2a

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

11. Function of Muscles Slide 6.8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Produce  Maintain  Stabilize  Generate

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

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

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

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

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

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

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

19. Properties of Skeletal Muscle Activity (single cells or fibers) Slide 6.13 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  I – ability to receive and respond to a stimulus  C – ability to shorten when an adequate stimulus is received

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

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

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

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

24. 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  Once started, muscle contraction cannot be

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

26. 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 myosin along the  The result is that the muscle is shortened Figure 6.7

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

28. Contraction of a Slide 6.19 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscle fiber contraction is  Within a skeletal muscle, not all fibers may be stimulated during the same  Different combinations of muscle fiber contractions may give differing responses  Graded responses – different degrees of skeletal muscle shortening, rapid stimulus = constant contraction or

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

30. Energy for Muscle Slide 6.23 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Initially, muscles used stored for energy  Bonds of ATP are broken to release  Only 4-6 seconds worth of ATP is stored by  After this initial time, other pathways must be utilized to produce

31. Energy for Muscle Contraction Slide 6.24 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Direct phosphorylation  Muscle cells contain creatine phosphate (CP)  CP is a high-energy molecule  After ATP is depleted, ADP is left  CP transfers energy to ADP, to regenerate  CP supplies are exhausted in about Figure 6.10a

32. Energy for Muscle Contraction Slide 6.26a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  glycolysis  Reaction that breaks down glucose without o  Glucose is broken down to pyruvic acid to produce some  Pyruvic acid is converted to Figure 6.10b

33. Energy for Muscle Contraction Slide 6.26b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Anaerobic glycolysis (continued)  This reaction is not as efficient, but is  Huge amounts of are needed  Lactic acid produces muscle Figure 6.10b

34. for Muscle Contraction for Muscle Contraction Slide 6.25 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Aerobic  Series of metabolic pathways that occur in the  Glucose is broken down to carbon dioxide and water, releasing  This is a slower reaction that requires continuous Figure 6.10c

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

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

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

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

39. Muscles and Body Movements Slide 6.30b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Muscles are attached to at least  Origin – attachment to a moveable  I – attachment to an immovable bone Figure 6.12

40. 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

41. Types of Ordinary Body Movements Slide 6.32 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  F – decreases angle of joint and brings two bones closer together  Extension- opposite of  Rotation- movement of a in longitudinal axis, shaking head “no”  Abduction/Adduction (see slides)  Circumduction (see slides)

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

43. Left: Abduction – moving the leg from the midline Above – Adduction- moving toward the Right: Circumduction: cone- shaped movement, proximal end doesn’t move, while distal end moves in a

44. Types of Muscles Slide 6.35 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  P mover – muscle with the major responsibility for a certain movement  A – muscle that opposes or reverses a prime mover  S – muscle that aids a prime mover in a movement and helps prevent rotation

45. Naming of Skeletal Muscles Slide 6.36a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Direction of muscle fibers  Example: rectus  Relative size of the muscle  Example: maximus

46. Naming of Skeletal Muscles Slide 6.36b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location of the muscle  Example: many muscles are named for (e.g., temporalis)  Number of origins  Example: triceps ( heads)

47. Naming of Skeletal Muscles Slide 6.37 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Location of the muscles origin and  Example: sterno (on the sternum)  Shape of the muscle  Example: deltoid  Action of the muscle  Example: flexor and extensor (flexes or extends a )

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

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

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

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

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

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

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

55. Disorders relating to the Muscular System Dystrophy: inherited, muscle enlarge due to increased fat and connective tissue, but fibers degenerate and atrophy Duchenne MD: lacking a protein to maintain the sarcolemma Myasthemia Gravis: progressive weakness due to a shortage of