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

6. Functions and Types of Muscle
Cardiac Muscle:

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

8. Functions and Types of Muscle
Skeletal Muscle:

9. 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

10. Functions and Types of Muscle
Connective Tissue Coverings:

11. 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

12. Contraction of Skeletal Muscle

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

14. 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

15. Creatine Phosphate Breakdown

16. 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

17. Cellular Respiration

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

19. Fermentation

20. 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

21. 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

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

23. 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

24. 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

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

26. 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

27. 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

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

29. Skeletal Muscles

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

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

32. 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

33. 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

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

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

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

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

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

39. 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

40. 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

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

42. 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

43. 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

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

45. 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

46. 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

47. 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

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

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