Muscular System: Functions, Structure, and Movement

1. Chapter 6Muscular System

2. Muscular System • ______ (how many) muscles in the human body • Functions • Moving the body’s framework • Maintaining posture • Producing ______ • Assisting ______ transport • Muscle mass makes up 40% of an average person’s body weight

3. Muscular System • Muscles are arranged in layers • All muscular movement is made possible through nerve impulses acting on tissue, causing ______ • Optimal function is achieved through muscles, tendons, ligaments, bones, and nerves working in concert

4. Word Parts Definition Example

5. Word Parts Definition Example

6. Word Parts Definition Example

7. Word Parts Definition Example

8. Word Etymology brevis short bucca cheek femur thigh gloutos buttock

9. Word Etymology pteron wing, feather pteryx wing rectur straight teres round, smooth vastus great

10. Medical Term Parts Used as Prefixes brachy- short bucco- cheek, mouth fascio- fascia pterygo- wing-shaped

11. Medical Term Parts Used as Suffixes - ______ nutrition, nourishment

12. Muscular System Preview • Key characteristic of muscle is its ability to ______ when stimulated by nerves to produce movement • Nerve impulse travels to muscle tissue, exciting the muscle to contract • Accomplished through functioning of several muscle structures that shorten to produce contraction

13. Structures of the Muscular System • Muscle cells/muscle fibers • Muscle tissue • ______ • ______ • ______

14. Muscular System Structure Key Terms muscle cells muscle fibers/myofibrils muscle fibers muscle cells muscle tissue tissue composed of contractile fibers

15. Muscular System Structure Key Terms sarcolemma ______ sarcoplasm ______ sarcomere ______

16. Muscle Fiber

17. Muscle Fiber • Individual muscle fiber has many parts • Sarcolemma = outer cell membrane • Sarcoplasm = cytosol within a muscle fiber • ______ = contractile fibers (thread-like) within muscle • Contain contractile proteins that enable muscle to contract • Sarcomeres = functional units of a myofiber that cause muscles to shorten

18. Muscle Tissue • Three types of muscle tissue • ______ • ______ • ______

19. Skeletal Muscle Tissue • Attaches to skeletal system by ______ • Provides movement • Also called ______ muscle • Voluntary control • Contracts and relaxes rapidly

20. Skeletal Muscle Tissue

21. Smooth Muscle Tissue • Nonstriated • Involuntary controlled • Appears nonstriped • ______ and ______ are lined by smooth muscle • Contracts and relaxes slowly

22. Smooth Muscle Tissue

23. Cardiac Muscle Tissue • Found only in the ______ • Permits constant pumping action • Appears ______ • Involuntary • Cardiac muscle fibers contract as a rhythmic unit and are self-stimulated

24. Cardiac Muscle Tissue

25. Muscle Tissue Key Terms skeletal muscle muscle associated with the skeleton ______ muscle muscle in viscera walls and blood vessels ______ progressive waves of contraction cardiac muscle heart muscle

26. Muscle Tissue Key Terms ______ fibrous bands or cords attaching muscle to bone or muscle to other body parts ______ tendon sheets fascia ______

27. Muscle Movement • Muscle movement is produced by pulling on bones • ______ = end of muscle that is attached to a immovable part • ______ = end of muscle that is attached to a movable part • When contraction occurs, one muscle typically produces movement in one direction, while another muscle produces movement in another direction. • ______ serve as levers • Joints serve as ______

28. Muscle Movement: Contraction • Occurs within the musculature • Requires • Motor neuron (nerve cell that excites a muscle) • Muscle fiber • Threshold stimulus (level of stimulation) must be exceeded • Results from a sliding movement within the myofibrils • Byproduct is ______

29. Muscle Movement • Energy is required • Molecules that supply energy are • ATP (______) • ATP supplies energy for muscle fiber contraction. • CP (______) • CP (present in muscle tissue and an energy-storing substance) synthesizes ATP as it decomposes • Active muscles depend on cellular ______

30. Muscle Movement: Muscle Fatigue • Occurs when a muscle loses its ability to contract • Results from • Interruption of blood supply to the muscle • Lack of ______ • Accumulation of ______ acid as a result of anaerobic respiration

31. Muscle Movement: Muscle Relaxation • Involves • Calcium ions (Ca2+) • ______(SR) = storage and release site of Ca2+ in a muscle fiber • After the Ca2+ is released, the SR reabsorbs the calcium, thereby halting the contraction process

32. Muscle Movement Key Terms origin muscle end that remains fixed during contraction insertion muscle end that moves during contraction ______ junctions myoneural junctions

33. Muscle Movement Key Terms ______ chemical involved in nerve impulse transmission adenosine ______ cell’s energy source myoglobin muscle hemoglobin, myohemoglobin

34. Muscle Tone • Resting tension • Sustained contraction of portions of skeletal muscle achieves muscle tone • Essential for posture and balance • Atrophy describes muscle tissue wasting as a result of • disease • ischemia • nutritional deficiencies • ______ is enlargement of muscle tissue (ex: muscle builders)

35. Muscle Tone Key Terms muscle tone muscle integrity achieved through active contraction of some fibers ______ physiologic or pathologic muscle size reduction hypertrophy ______

36. Basis for Naming Skeletal Muscles • Location • Fiber direction • ______ • Number of ______ • ______ • Origin • ______ • Action • Point of achievement

37. Naming Skeletal Muscles Key Terms abductors muscles that draw a body part ______ when contracted adductors muscles that draw a body part ______ when contracted

38. Naming Skeletal Muscles Key Terms extensors muscles that ______ or ______ a limb or part flexors muscles that ______ or ______ a limb or part

39. Pathology of Muscle System • Signs and symptoms • Muscle pain • Muscle weakness • Muscle disorders usually result from • Trauma • Tumor • Immune disorder • Improper nerve conduction • Inheritance • Infection

40. Types of Muscle Diseases: Myopathy • Myopathy—disease of the muscles and muscle tissues that is either inherited or acquired • Acquired • ______ • ______ • Inherited • ______(MDs) • ______

41. Botulism • Serious form of food poisoning • Caused by eating contaminated food • Contains toxin: ______, the most potent poison known • Signs and symptoms • Double vision • Light sensitivity • Blurred speech • Nausea • Vomiting • Inability to walk—muscle weakness

42. Botulism (cont’d) • Treatment • Guanidine hydrochloride • Pulmonary ventilation • Recovery is gradual—up to 1 year

43. Fibromyalgia • Unknown origin • Characteristics • Myalgia, stiffness • Tenderness • Signs and symptoms • Fibrosis • Fibrositis

44. Fibromyalgia (cont’d) • Joint regions involved • Antecubital • Cervical • Sacroiliac • Patellar • Diagnosis • Patient history and physical exam

45. Fibromyalgia (cont’d) • Treatment • Most common • Analgesics • Aspirin • NSAIDs • Proven successful • Chiropractic adjustments • Physical therapy • Medical massage

46. Muscular Dystrophies (MDs) • Inherited disease/genetic disorder • Characteristics • Degeneration of muscle cells causing progressive muscle weakness • Muscles replaced by fat and connective tissue • Types • ______ muscular dystrophy (DMD) is the most common type • ______ MD is an x-linked genetic disorder affecting only males

47. Muscular Dystrophies (cont’d) • Diagnosis • Blood tests • Urine tests • Treatment • Physical therapy • Occupational therapy

48. Myasthenia Gravis • Autoimmune disease • Weakness of ______ muscles • Affects more women than men • Signs and symptoms • difficulty in chewing, swallowing, and talking • Diagnosis • history and physical examination • Treatment • cholinesterase inhibitors • corticosteroid therapy

49. Polymyositis (PM) • Autoimmune disease • Causes myositis, myomalacia ,and atrophy • Affects mainly women • Signs and symptoms • Inability to raise arms over the head • Difficulty in walking

50. Polymyositis (cont’d) • Diagnosis • History • Physical examination • Treatment • Steroids to minimize inflammation • Immunosuppressants • Physical therapy • Medical massage