1. Chapter 7
Muscular System

2. Functions and Types of Muscle
Has three types
Smooth
Cardiac
Skeletal

3. Functions and Types of Muscle
Smooth Muscle:
Wall of hollow internal organs
Involuntary contractions
Moves materials
Single nucleus
Parallel lines, forming sheets
No striations
Sustain prolonged contraction, doesn’t fatigue easy

4. Functions and Types of Muscle
Smooth Muscle:

5. Functions and Types of Muscle
Smooth Muscle:

6. Functions and Types of Muscle
Cardiac Muscle:
Wall of heart
Uninucleiated
Striated, tubular, and branched
Intercalated disks = quick contractions
Involuntary and rhythmic

7. Functions and Types of Muscle
Cardiac Muscle:

8. Functions and Types of Muscle
Cardiac Muscle:

9. Functions and Types of Muscle
Skeletal Muscle:
Multinucleated
Striated
Voluntary

10. Functions and Types of Muscle
Skeletal Muscle:

11. Functions and Types of Muscle
Skeletal Muscle:

12. Functions and Types of Muscle
Connective Tissue Coverings:
Endomysium: each muscle fiber is surrounded by
Fascicles: groups of muscle fibers
Perimysium: Connective tissue covering of fascicles
Epimysium: Covers the entire muscle

13. Functions and Types of Muscle
Connective Tissue Coverings:

14. Functions and Types of Muscle
Skeletal muscle:
Supports the body
Makes bones and other body parts move
Helps maintain a constant body temperature
Contraction assists movement in cardiovascular and lymphatic vessels
Protects internal organs and stabilizes joints

15. Contraction of Skeletal Muscle
Sarcolemma: plasma membrane
Sarcoplasm: cytoplasm
Contains glycogen for energy
Contains myoglobin that binds oxygen
Sarcoplasmic reticulum: endoplasmic reticulum
Encases myofibrils- contractile portion of muscle fibers

16. Contraction of Skeletal Muscle
Sarcomeres- units of myofibrils
Contain myosin: thick protein filament
Contain actin: thin protein filament

17. Contraction of Skeletal Muscle

18. Contraction of Skeletal Muscle
Thick filaments
Made of hundreds of protein myosin

19. Contraction of Skeletal Muscle
Thin filaments
Made of two intertwining strands of protein actin

20. Actin and Myosin

21. Contraction of Skeletal Muscle
Neuromuscular junction: the area between the axon terminal and the sarcolemma

22. Neuromuscular Junction

23. Contraction of Skeletal Muscle
Actin- surrounded by threads of tropomyosin and troponin
Calcium ions bind with troponin and expose myosin binding sites
ATP binds to myosin and is broken down to ADP and P
Energy is released, contraction occurs

24. Contraction of Skeletal Muscle

25. Contraction of Skeletal Muscle
Muscles acquire ATP in 3 ways
Creatine phosphate breakdown
Cellular respiration
Fermentation

26. Contraction of Skeletal Muscle
Creatine Phosphate Breakdown
Creatine Phosphate builds up when muscle is at rest
Speediest way to make ATP available
8 seconds of intense energy

27. Creatine Phosphate Breakdown

28. Contraction of Skeletal Muscle
Cellular Respiration:
Completed in mitochondria
Only when oxygen is available
From glycogen and fatty acids
End products are carbon dioxide, water, and heat

29. Cellular Respiration

30. Contraction of Skeletal Muscle
Fermentation:
Anaerobic
Glucose breaksdown into lactic acid
Build up of lactic acid leads to cramping

31. Fermentation

32. Contraction of Skeletal Muscle
All or nothing law
A single fiber either contracts or rest
However, a group of fibers some contract and other will not to appear to have the ability for partial contractions

33. Contraction of Skeletal Muscle
Muscle twitch- single contraction that last for a fraction of a second
Latent period: time between stimulation and initiation of contraction
Contraction period: muscle shortens
Relaxation period: muscle returns to its former length

34. Contraction of Skeletal Muscle
Summation – increase in muscle contraction until maximal sustained contraction is achieved
Tetanic contraction- maximum contraction

35. Contraction of Skeletal Muscle
Innervated- muscle fibers are innervated with nerve fibers called a motor unit
Motor units either contract or do not contract
Recruitment- stronger and stronger muscle contractions

36. Contraction of Skeletal Muscle
While some muscles are contracting others are resting, this helps prevent fatigue
Tone: some fibers are always contracting
Helps maintain posture

37. Contraction of Skeletal Muscle
Atrophy- loss of muscle tone due to inactivity or nerve damage
Muscle will eventually be replaced by adipose and fibrous tissue
Muscles will shorten, leaving parts contracted

38. Contraction of Skeletal Muscle
Pertrophy- increase in muscle size
Prolonged period of forceful muscular activity increases myofibrils

39. Contraction of Skeletal Muscle
Slow-twitch muscles
Steadier and more endurance
Highly resistant to fatigue
Substantial reserve of glycogen and fat
Abundant mitochondria, few fibers
Aerobic

40. Contraction of Skeletal Muscle
Fast-twitch muscles
Anaerobic
Designed for strength
Many fibers, few mitochondria
Little or no myoglobin
Few blood vessels
Vulernable to cramping

41. Skeletal Muscles Origin – of a muscle is on the stationary bone
Insertion- of a muscle in on the bone that moves

42. Skeletal Muscles

43. Skeletal Muscles Prime mover- the muscle that does most of the work
Synergists- the assisting muscles

44. Skeletal Muscles
Antagonist- pair of muscles working against the synergist

45. Skeletal Muscles Naming muscles Size Shape Direction of fiber Location
Example: gluteus maximus, largest butt muscle
Shape
Deltoid, shaped like a delta
Direction of fiber
Rectus abominis, rectus = straight
Location
Frontalis, overlies the frontal bone

46. Skeletal Muscles Naming muscles Attachment Number of attachments
Ex. Brachioradialis, brachium and the radius
Number of attachments
Ex. Bicep = two attachments
Action
Extensor digitorum – extends fingers

47. Skeletal Muscles

48. Skeletal Muscles Muscles of the Head Frontalis: frontal bone
Raising eyebrows, wrinkle brow
Orbicularis oculi: encircles eye
blinking
Orbiularis oris: encircles mouth
Pucker lips

49. Skeletal Muscles Muscles of the Head Buccinator: cheek
Compresses to whistle
Zygomaticus: cheekbone to corner of mouth
Smile

50. Skeletal Muscles Muscles of Mastication
Masseter: zygomatic arch to mandible
Ex. chewing
Temporalis: overlies temporal bone
Ex. Elevates mandible

51. Skeletal Muscles Muscles of the Neck
Deep neck muscles are responsible for chewing
Superficial muscles are responsible for moving the head

52. Skeletal Muscles Muscles of the Neck Sternocleidomastoid Trapezius
Turns head from right to left
Trapezius
Triangular
Shrug shoulders

53. Skeletal Muscles Muscles of the Trunk
External intercostal: between ribs
Ex. Elevate rib cage during inspiration
Diaphragm
Ex. Assists in inspirations
Internal intercostal
Ex. Normally no muscular contraction, only with forced expiration

54. Skeletal Muscles Muscles of the Abdominal Wall
External and internal obliques: Lower ribs and pelvic girdle
Ex. Trunk rotation and lateral flexion
Transversus abdomininis: horizontal across abdomen
Synergist muscles
Rectus abdominis: from pubic bones to the ribs and strernum
Ex. Flex and rotate lumbar region

55. Skeletal Muscles Muscles of the Shoulder
Serratus anterior: from armpit to chest
Ex. Helps elevate arm above head

56. Skeletal Muscles Muscles of the Arm Deltoid Pectoralis major
Abducts arm to horizontal position
Pectoralis major
Latissimus dorsi: from lower spine to humerus
Ex. Swimming, rowing and climbing rope
Rotator cuff: muscles over proximal humerus

57. Skeletal Muscles Muscles of the Arm
Biceps brachii: muscles of the forearm
Turn a doorknob unscrew a jar
Brachilais: humerus to ulna
Ex. Flexing the forearm
Triceps brachii: scapula to humerus
Ex. To punch and in tennis

58. Skeletal Muscles Muscles of the Arm Flexor carpi and extensor carpi
Flexes and extends wrist
Flexor digitorum and extensor digitorum
Flexes or extends fingers

59. Skeletal Muscles Muscles of the Hip and Leg
Iliopsoas: ilium to lumbar vertebrae
Ex. walking, bowing, standing erect
Gluteus maximus: large buttocks muscle
Ex. Walking, jumping, climbing stairs
Gluteus medius: small buttocks muscle
Adductor group
Ex. Thighs inward

60. Skeletal Muscles Muscles of the Leg Quadricep femoris: thigh
Ex. Extends leg
Sartorius: thigh to knee
Ex. Sit cross legged
Hamstring:Back of thigh
Ex. Antagonist muscle group

61. Skeletal Muscles Muscles of the Ankle and Foot Gastrocnemius
Ex. Pushing forward while walking, dancing
Tibialis anterior
Ex. Inversion of foot
Peroneus
Ex. Plantar flexion
Flexor and extensor digitorum longus
Ex. Flexes and extends toes

62. Effects of Aging Mass and strength decrease
Muscle tissue initially replaced by connective tissue then eventually fat

63. Homeostasis Heartbeat and movement of blood Protect internal organs
Moves bones and allows daily activities