1. Memmler’s The Human Body in Health and Disease 11th edition
Chapter 8
The Muscular System

2. Types of Muscle
Smooth
Cardiac
Skeletal

3. Smooth Muscle
Makes up walls of hollow body organs, respiratory passageways
Involuntary movement
Cell structure
Tapered ends
Single, central nucleus
No visible bands (striations)
Stimulated by nerve impulses, hormones, stretching

4. Cardiac Muscle Makes up wall of heart Involuntary movement
Cell structure
Branching interconnections
Single, central nucleus
Striated
Membranes are intercalated disks
Stimulated by electrical impulses, nervous stimuli, hormones

5. Skeletal Muscle Attached to bones, muscles, or skin Voluntary movement
Cell structure
Long and cylindrical
Multiple nuclei per cell
Heavily striated
Stimulated by nervous system

6. Checkpoint 8-1: What are the three types of muscle?

7. Question: Which type of muscle has intercalated disks. a
Question: Which type of muscle has intercalated disks? a. smooth muscle b. cardiac muscle c. skeletal muscle

8. Answer: b. cardiac muscle

9. The Muscular System Skeletal muscle has three primary functions
Skeletal movement
Posture maintenance
Heat generation

10. Checkpoint 8-2: What are the three main functions of skeletal muscle?

11. Structure of a Muscle Fascicles (muscle fibers) Endomysium Perimysium
Epimysium (deep fascia)
Tendons

12. Structure of a skeletal muscle.
Structure of a muscle showing the tendon that attaches it to a bone. (B) Muscle tissue seen under a microscope. Portions of several fascicles are shown with connective tissue coverings.
ZOOMING IN • What is the innermost layer of connective tissue in a muscle? • What layer of connective tissue surrounds a fascicle of muscle fibers?

13. Question: What is the name of the connective tissue structure that connects muscle to bone? a. fascicle b. ligament c. tendon

14. Answer: c. tendon

15. Muscle Cells in Action
Motor unit is a single neuron and all the muscle fibers it
stimulates
Neuromuscular junction (NMJ)
Neurotransmitter
Synaptic cleft
Receptors
Motor end plate

16. Checkpoint 8-3: Muscles are activated by the nervous system
Checkpoint 8-3: Muscles are activated by the nervous system. What is the name of the special synapse where a nerve cell makes contact with a muscle cell?
Checkpoint 8-4: What neurotransmitter is involved in the stimulation of skeletal muscle cells?

17. Neuromuscular junction (NMJ).
(A) The branched end of a motor neuron makes contact with the membrane of a muscle fiber (cell). (B) Enlarged view of the NMJ showing release of neurotransmitter (acetylcholine) into the synaptic cleft.
(C) Acetylcholine attaches to receptors in the motor end plate, whose folds increase surface area. (D) Electron microscope photograph of the neuromuscular junction.

18. Properties of Muscle Tissue
Excitability
Action potential
Contractility
Actin
Myosin
Sarcomere
ATP

19. Sliding filament mechanism of skeletal muscle contraction.
Muscle is relaxed and there is no contact between the actin and myosin filaments.
Cross-bridges form and the actin filaments are moved closer together as the muscle fiber contracts. (C) The cross-bridges return to their original position and attach to new sites to prepare for another pull on the actin filaments and further contraction. 
 ZOOMING IN • Do the actin or myosin filaments change in length as contraction proceeds?

20. Checkpoint 8-5: What are two properties of muscle cells that are needed for response to a stimulus?
Checkpoint 8-6: What are the filaments that interact to produce muscle contraction?

21. The Role of Calcium Calcium
Is released when nerve fiber stimulates muscle cell
Attaches to proteins blocking receptor sites
Allows cross-bridges to form between actin and myosin
Returns to endoplasmic reticulum (ER), which is called “sarcoplasmic reticulum” in muscle cells.

22. Energy Sources
Muscle contraction requires energy (ATP), oxidized in muscle cells from
Oxygen
Glucose or other usable nutrient
Compounds in muscle cells that store oxygen, energy, or nutrients
Myoglobin
Glycogen
Creatine phosphate

23. Checkpoint 8-7: What mineral is needed to allow actin and myosin to interact?
Checkpoint 8-8: Muscle cells obtain energy for contraction from the oxidation of nutrients. What compound is formed in oxidation that supplies the energy for contraction?

24. Oxygen Consumption Aerobic glucose metabolism
Anaerobic glucose metabolism
Inefficient production
Lactic acid accumulation
Oxygen debt
Recovery oxygen consumption

25. Checkpoint 8-9: When muscles work without oxygen, a compound is produced that causes muscle fatigue. What is the name of this compound?

26. Effects of Exercise Improved balance, joint flexibility
Increase in muscle size (hypertrophy)
Improvements in muscle tissue
Vasodilation
Strengthened heart muscle
Improved breathing and respiratory efficiency
Weight control
Stronger bones

27. Types of Muscle Contractions
Partial (muscle tone or tonus)
Isotonic
No change in tension
Muscle length shortens
Movement
Isometric
Great increase in tension
Muscle length unchanged
No movement

28. Question: The partially contracted state of muscle is known as what. a
Question: The partially contracted state of muscle is known as what? a. tonus b. tension c. torsion

29. Answer: a. tonus

30. The Mechanics of Muscle Movement
Tendons attach muscles to bones
Origin—attached to more fixed part of skeleton
Insertion—attached to more moveable part of skeleton

31. Checkpoint 8-10: Muscles are attached to bones by means of tendons: one attached to a less movable part of the skeleton and one attached to a movable part. What are the names of these two attachment points?

32. Muscles Work Together Many muscles function in pairs Prime movers
Antagonists
Synergists
In development, nervous system must learn to coordinate movement. Children learning new skills may use some muscles unnecessarily or not use the correct muscles.

33. Checkpoint 8-11: Muscles work together to produce movement
Checkpoint 8-11: Muscles work together to produce movement. What is the name of the muscle that produces a movement as compared with the muscle that produces an opposite movement?

34. Question: What is the name for a muscle that helps the prime mover and the antagonist muscles? a. a supplemental b. an effector c. a synergist

35. Answer: c. a synergist

36. Levers and Body Mechanics
Musculoskeletal system as a lever system
Lever—bone
Fulcrum—joint
Force—applied by muscle
Three classes of levers
First class
Second class
Third class—most body systems

37. Three classes of levers are shown along with tools and anatomic examples that illustrate each type.
R = resistance (weight);
E = effort (force);
F = fulcrum (pivot point).

38. Checkpoint 8-12: Muscles and bones work together as lever systems
Checkpoint 8-12: Muscles and bones work together as lever systems. Of the three classes of levers, which one represents the action of most muscles?

39. Skeletal Muscle Groups
Characteristics for naming muscles (often combined)
Location
Size
Shape
Direction of fibers
Number of heads (attachment points)
Action

40. Superficial muscles, anterior view.
Associated structure is labeled in parentheses.

41. Superficial muscles, posterior view.
Associated structures are labeled in parentheses.

42. Muscles of the Head Facial expression (orbicularis) muscles
Orbicularis oculi
Orbicularis oris
Levator palpebrae superioris
Buccinator
Mastication (chewing) muscles
Temporalis
Masseter
Intrinsic
Extrinsic

43. Muscles of the head.
Associated structure is labeled in parentheses.  
ZOOMING IN
• Which of the muscles in this illustration is named for a bone it is near?

44. Question: What is the name for the muscle that surrounds the eye. a
Question: What is the name for the muscle that surrounds the eye? a. orbicularis oculi b. orbicularis oris c. frontalis

45. Answer: a. orbicularis oculi

46. Muscles of the Neck Are ribbonlike Extend up, down, or obliquely
Extend in several layers in a complex manner
Most common is sternocleidomastoid

47. Muscles of the Upper Extremities
Position the shoulder
Move the arm
Move the forearm and hand

48. Muscles That Move the Shoulder and Arm
Trapezius
Latissimus dorsi
Pectoralis major
Serratus anterior
Deltoid
Rotator cuff
Supraspinatus
Infraspinatus
Teres minor
Subscapularis

49. Muscles That Move the Forearm and Hand
Brachialis
Biceps brachii
Brachioradialis
Triceps brachii
Flexor carpi
Extensor carpi
Flexor digitorum
Extensor digitorum

50. Muscles that move the forearm and hand.

51. Muscles of the Trunk Breathing muscles Abdominal muscles
Pelvic floor muscles
Deep back muscles

52. Muscles of Respiration
Diaphragm
Intercostal muscles

53. Muscles of respiration.
Associated structures are also shown.

54. Checkpoint 8-13: What muscle is most important in breathing?

55. Muscles of the Abdomen and Pelvis
External oblique
Internal oblique
Transversus abdominis
Rectus abdominis
Levator ani

56. Muscles of the abdominal wall
Muscles of the abdominal wall. Surface tissue is removed on the right side to show deeper muscles.
Associated structures are labeled in parentheses.

57. Muscles of the female perineum (pelvic floor).
Associated structures are labeled in parentheses.

58. Checkpoint 8-14: What structural feature gives strength to the muscles of the abdominal wall?

59. Deep Muscles of the Back
Erector spinae
Deeper muscles in the lumbar area

60. Muscles of the Lower Extremities
Among the longest and strongest in the body
Specialized for locomotion and balance

61. Muscles That Move the Thigh and Leg
Gluteus maximus
Gluteus medius
Iliopsoas
Adductors
Sartorius
Iliotibial (IT) tract
Hamstrings

62. Muscles of the thigh.
Associated structures are labeled in parentheses.

63. Question: What is the name of the thickened band of fascia that covers the lateral thigh muscles? a. sartorius b. adductor longus c. ileotibial tract

64. Answer: c. ileotibial tract

65. Muscles That Move the Foot
Gastrocnemius
Achilles tendon
Soleus
Tibialis anterior
Peroneus longus
Flexor and extensor muscles

66. Muscles that move the foot.
Associated structures are labeled in parentheses

67. Effects of Aging on Muscles
Beginning at about age 40
Gradual loss of muscle cells
Loss of power
Tendency to flex hips and knees
Decrease in height

68. Muscular Disorders Spasms Colic Seizure or convulsion Cramps Strains
Sprains
Atrophy

69. Question: True or False
Question: True or False?: A strain is a more serious muscle injury than a sprain.

70. Answer: False: A sprain, which usually involves a ligament tear, is more serious than a strain.

71. Diseases of Muscles Muscular dystrophy Myasthenia gravis Myalgia
Myositis
Fibrositis
Fibromyositis
Fibromyalgia syndrome (FMS)

72. Disorders of Associated Structures
Bursitis
Bunions
Tendinitis
Tenosynovitis
Shinsplints
Carpal tunnel syndrome

73. End of Presentation