The Muscular System

1. 25 The Muscular System

2. Learning Outcomes (cont.) 25.1Describe the functions of muscle. 25.2Compare the three types of muscle tissue including their locations and characteristics. 25.3 Explain how muscle tissue generates energy. 25.4Describe the structure of a skeletal muscle.

3. Learning Outcomes (cont.) 25.5Recognize the terms origin and insertion. 25.6 Identify the major skeletal muscles of the body, giving the action of each. 25.7Summarize the changes that occur to the muscular system as a person ages. 25.8 Describe the causes, signs and symptoms, and treatments of various diseases and disorders of the muscular system.

4. Introduction • Muscles contract and relax to cause movement • 600 individual muscles in the body You will focus on the differences among three muscle tissue types, the structure of skeletal muscles, muscle actions, and the names of skeletal muscles.

5. Functions of Muscle • The ability to contract enables muscles to • Allow movement • Provide stability • Control body openings and passages • Warm the body

6. Functions of Muscle (cont.) • Skeletal muscles • Attach to bones by tendons • Contractions result in movement • Smooth muscle – contractions move organ contents • Cardiac muscle – contractions pump blood from the heart

7. Functions of Muscle (cont.) • Stability • Hold bones tightly together • Small muscles hold vertebrae together • Heat Production • Heat is released when muscles contract • Helps maintain a normal temperature

8. Control of Body Openings and Passages • Sphincters • Valve-like structures • Control movement in and out of passages

9. tendons in and out Apply Your Knowledge ANSWER: True or False: ___ Skeletal muscles are attached to bones by ligaments. ___ Contractions of smooth muscle produce movement of organ contents. ___ Cardiac muscle produces atrial and ventricular contractions. ___ Sphincters control movement of substances out of passages. ___ Heat is released as muscles relax. F T T F RIGHT! F contract

10. Types of Muscle Tissue • Muscle cells or myocytes – muscle fibers • Sarcolemma • Sarcoplasm • Sarcoplasmic reticulum • Myofibrils • Long structures in sarcoplasm • Striations – arrangement of filaments Muscle structure

11. Muscle Group Major Location Major Function Mode of Control Skeletal Muscle Attached to bones and skin of the face Produces body movements and facial expressions Voluntary Smooth Muscle Walls of hollow organs, blood vessels, and iris Moves contents through organs; vasoconstriction Involuntary Cardiac Muscle Wall of the heart Pumps blood through heart Involuntary Types of Muscle Tissue (cont.)

12. Skeletal Muscle • Skeletal muscle fibers • Contract in response to the neurotransmitter acetylcholine • After contraction, muscles release the enzyme acetylcholinesterase • Breaks down acetylcholine • Allows muscle to relax

13. Smooth Muscle • Multiunit smooth muscles – respond to neurotransmitters and hormones • Visceral smooth muscles • Responds to neurotransmitters ~ acetylcholine and norepinephrine • Stimulate each other to contract ~ peristalsis

14. Cardiac Muscle • Intercalated discs • Connect groups of cardiac muscle • Allow the heart to work as a pump • Self-exciting • Responds to neurotransmitters • Acetylcholine • Norepinephrine

15. Apply Your Knowledge Match the following: ___ Self-exciting ___ Contract in response to acetylcholine___ Stimulate each other to contract ___ Peristalsis ___ Slowed by acetylcholine ___ Voluntary movement ANSWER: Skeletal Muscle Smooth muscle Cardiac muscle C A B B Very Good! C A

16. Production of Energy for Muscle • ATP • Muscle cells make ATP by • Creatine phosphate ~ rapid production of energy • Aerobic respiration ~ uses body’s store of glucose • Lactic acid production from pyruvic acid

17. To liver for conversion to glucose, requiring more energy and oxygen to make ATP Oxygen Debt Strenuous use of skeletal muscles depletes cells of oxygen Pyruvic Acid Lactic acid Muscle fatigue Oxygen debt

18. Muscle Fatigue • Loses ability to contract • Causes • Accumulation of lactic acid • Interruption of the blood supply • Acetylcholine not released by motor neuron

19. Apply Your Knowledge ANSWER: Match the following: ___ Rapid production of energy ___ Needed for sustained or repeated muscle contractions ___ Uses body’s store of glucose ___ Muscle fatigue ___ With strenuous exercise, converts to lactic acid • Lactic acid • Pyruvic acid • ATP • Aerobic respiration • Creatine phosphate E C D A B Yippee!

20. Structure of Skeletal Muscles • Skeletal muscles – the major organs of the muscular system • Composition • Connective tissue • Skeletal muscle tissue • Blood vessels • Nerves

21. Structure of Skeletal Muscles (cont.) • Connective tissue coverings • Fascia • Tendon • Aponeruosis • Epimysium • Perimysium • Endomysium Muscle structure

22. Apply Your Knowledge Match the following: __ Thin covering under the fascia that surrounds the muscle __ Separates muscles from each other __ Connects muscles to bones __ Divides a muscle into sections called fascicles __ Surrounds individual muscle cells __ Attaches muscles to other muscles ANSWER: D • Tendon • Perimysium • Aponeurosis • Epimysium • Fascia • Endomysium E A B F C Excellent!

23. Attachments and Actions of Skeletal Muscles • Attachment types • Origin~ for a less movable bone • Insertion ~ for a more movable bone

24. Attachments and Actions of Skeletal Muscles (cont.) • Movement • Prime mover (agonist) ~ responsible for most of the movement • Synergists~ help the prime mover by stabilizing joints • Antagonist ~ produces movement opposite to prime mover

25. Flexion Extension Hyperextension Dorsiflexion Attachments and Actions of Skeletal Muscles (cont.) • Plantar flexion • Abduction • Adduction Figure of Body Movements

26. Rotation Circumduction Pronation Supination Attachments and Actions of Skeletal Muscles (cont.) Supination Pronation Circumduction Rotation

27. Attachments and Actions of Skeletal Muscles (cont.) • Inversion • Eversion • Retraction • Protraction • Elevation • Depression Figure of movements

28. Apply Your Knowledge True or false? An agonist is the muscle that produces a movement opposite to a prime mover. Synergists stabilize joints. Origin is an attachment site for the less moveable bone during muscle contraction. Insertion is an attachment site for the more moveable bone during muscle contraction. ANSWER: F antagonist T T T Correct!

29. Major Skeletal Muscles • Name often describes muscle by • Location • Size • Action • Shape • Number of attachments

30. Muscles of the Head • Sternocleidomastoid • Splenius capitis • Muscles of the jaw • Masseter • Temporalis • Muscles of facial expression • Frontalis • Orbicularis oris • Orbiuclaris oculi • Zygomaticus • Platysma Skeletal muscles

31. Arm Muscles • Pectoralis major • Latissimus dorsi • Deltoid • Subscapularis • Infraspinatus Skeletal muscles

32. Arm Muscles(cont.) • Biceps brachii • Brachialis • Brachioradialis • Triceps brachii • Supinator • Pronator teres Skeletal muscles

33. Muscles of the Wrist, Hand, and Fingers • Flexor carpi radilas • Felxor carpi ulnaris • Palmaris longus • Flexor digitorum profundus • Extensor carpi radialis longus and brevis • Extensor carpi ulnairs • Extensor digitorum Diagram of hand

34. Respiratory Muscles • Diaphragm • Separates thoracic and abdominal cavities • Contracts for inspiration • External and internal intercostals – expand and lower the ribs For diagram

35. Skeletal Muscles (cont.) • Abdominal muscles • External and internal obliques • Transverse abdominis • Rectus abdominis • Muscles of the Pectoral Girdle • Trapezius • Pectoralis minor For diagram

36. Leg Muscles • Iliopsoas major • Gluteus maximus • Gluteus medius and minimus • Adductor longus and magnus Skeletal muscles

37. Leg Muscles (cont.) • Biceps femoris, semitendinosus, and semimembranosus • Rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius • Sartoris Skeletal muscles

38. Ankle, Foot, and Toe Muscles • Tibialis anterior • Extensor digitorum longus • Gastrocnemius • Soleus • Flexor digitorum longus Skeletal muscles

39. Apply Your Knowledge ANSWER: Matching: raises the eyebrows chewing expand and lower ribs compress the abdominal wall extends the thigh extends the leg at the knee • Gluteus maximus • Intercostals • Frontalis • Quadriceps group • Obliques • Masseter C F B E A D Bravo!

40. Aging and the Musculoskeletal System • Speed and strength of muscle contractions decrease • Aging • Decreased dexterity and gripping ability • Decreased mobility • Assistive devices helpful • Routine exercise

41. Diseases and Disorders of the Muscular System

42. Diseases and Disorders of the Muscular System(cont.)

43. Diseases and Disorders of the Muscular System(cont.)

44. Apply Your Knowledge What changes occur to the muscular system as a result of aging? • ANSWER: Speed and strength of muscle contractions decrease with aging. • The aging process results in: • Decreased dexterity and gripping ability • Decreased mobility Good Job!

45. Apply Your Knowledge ANSWER: True or False: Botulism is a condition resulting in chronic pain in joints, muscles and tendons. Kidney damage due to toxins released by serious muscle injuries is the condition called rhabdomyolysis. Tetanus is caused by a toxin and causes muscle spasms in the jaw, neck, and facial muscles. Lockjaw is caused by spasm or shortening of the sternocleidomastoid muscle. Fibromyalgia F T T Torticollis F Good Job!

46. In Summary 25.1 The functions of muscles include movement, stability, control of body openings and passages, and the production of heat. Valve- like muscular structures called sphincters control passage of substances into and out of organs like the stomach and bladder. .25.2The three types of muscle tissue are striated, voluntary skeletal muscle; smooth, involuntary visceral muscle; and specialized striated and involuntary cardiac muscle.

47. 25.3 There are three ways muscles create energy. Creatine phosphate, aerobic respiration, and lactic acid production. 25.4Skeletal muscle is composed of connective tissues, skeletal muscle tissue, blood vessels, and nerves. The coverings of skeletal muscles include fascia, tendon, aponeurosis, epimysium, perimysium, and endomysium. In Summary (cont.)

48. In Summary (cont.) 25.5The origin of a muscle is the attachment site of the muscle to the less moveable bone during muscle contraction. The insertion of a muscle is the attachment site for the muscle to the more moveable bone during muscle contraction. 25.6The major muscles of the head and the upper extremity, major respiratory muscles, abdominal muscles, pectoral girdle muscles and those of the lower extremity are covered in this learning outcome.

49. In Summary (cont.) 22.7 The common diseases of aging include arthritis, fractures, osteoporosis, and muscular decline. Aging causes a decline in strength and speed of muscle contractions. Dexterity and gripping abilities lessen and mobility often decreases related to skeletal and muscular decline. 22.8 There are many common diseases and disorders of the muscular system with varied signs, symptoms, and treatments.

50. End of Chapter 25 Everyone has a ‘risk muscle.’ You keep it in shape by trying new things. If you don’t, it atrophies. Make a point of using it at least once a day. ~Roger von Oech