1. 7
The Muscular
System: Movement
for the Journey

2. Muscular System Overview
 Muscle: general term
for all contractile tissue
 Contractile property of
muscle tissue allows it
to become short and
thick in response to
nerve impulse and then
to relax once impulse
removed
 Alternative contraction
and relaxation causes
movement

3. Muscular System Overview
 Muscle cells
elongated;
resemble fibers
such as those in
rope
 Muscle tissue
constructed of
bundles of these
fibers, each
approximately
the diameter of a
human hair

4. Types of Muscles

5. Types of Muscles
Skeletal muscles
 Voluntary muscles
 Under conscious control
 Derive name from attachment of
muscle to skeletal system
 Striated (striped) muscle

6. Types of Muscles
 Smooth muscles
 Involuntary muscles
 Not under our conscious control
 Does not have striped appearance
 Found within certain organs, blood vessels,
airways; sometimes called visceral muscle

7. Types of Muscles
 Smooth muscles
 Allows for internal movement of food
 Facilitates movement of blood by
changing diameter of blood vessels

8. Types of Muscles
 Cardiac muscle
 Involuntary; specialized muscle with
striated appearance
 Found solely in heart
 Contraction of muscle causes heart
contract; internal movement
(circulation) of blood

9. Figure 7-1
The three types of muscle:
skeletal, cardiac, and smooth.

10. Test Your Knowledge
Review 4 Questions
for Section 7-1

11. Skeletal Muscles
 Attached to bones, provide movement
for body
 Tendons: fibrous tissues that attach
skeletal muscles to bones
 Ligaments: attach bone to bone
 Some muscles attach directly to
bone or soft tissue without tendon

12. Skeletal Muscles
 Called voluntary
because movement
controlled by conscious
thought
 Responsible for
movement, giving body
its shape and form,
maintaining body
posture, and heat
generation

13. Figure 7-2
Anterior and posterior view of
major muscles.
Shoulder
Thoracic
Arms & Legs
Ribs

14. Figure 7-2 (continued)
Anterior and posterior view of
major muscles.
Buttocks

15. Figure 7-3
Skeletal facial muscles.

16. Figure 7-4
Skeletal muscles of the posterior
and anterior trunk

17. Figure 7-5
Skeletal muscles of the shoulder,
arm, and hand

18. Figure 7-6
Skeletal muscles of the
hip and leg

19. Contraction and Relaxation

20. Figure 7-7
Coordination of antagonistic
muscles to perform movement.
Muscles that cause movement are called
agonists or primary movers

21. Contraction and Relaxation

22. Contraction and Relaxation
 Diaphragm: primary
Diaphragm
mover of breathing
 Dome-shaped muscle
separates abdominal
cavity and thoracic
cavity
 Responsible for
performing major work
of bringing atmospheric
air into lungs
 Muscle under both
voluntary and
involuntary control

23. Figure 7-8
The diaphragm: The major
muscle of breathing

24. Movement Terminology
 Rotation: circular movement
Rotation
that occurs around an axis
 Abduction: to move away from
Abduction
midline of body
 Adduction: movement toward
Adduction
midline of body

25. Figure 7-9
The types of skeletal movement
Extension of left forearm.
Extension:
Extension
Increasing angle
between two bones
connected at a joint
Muscle that
straightens the
joint is called
extensor muscle

26. Figure 7-9
The types of skeletal movement
Flexion of left forearm
Flexion:
Flexion
Opposite of
extension,
decreasing angle
between two bones
Muscle that
bends the joint is
called flexor
muscle

27. Figure 7-9 (continued)
The types of skeletal movement
Flexion and extension of the leg
Extension is needed when you kick a football
Flexion occurs when you bend your leg to sit down

28. Ataxia
Some muscular
diseases can cause
ataxia, a condition
ataxia
of irregular muscle
movement and lack
of muscle
coordination

29. Test Your Knowledge
Review 9 Questions
for Section 7-2

30. Muscular Movement at the
Cellular Level
How does this
muscle tissue
cause a
coordinated and
smooth
contraction?

31. Muscle Contraction
Step-by-Step
Begins at the Neuromuscular Junction

32. MUSCLE TISSUE
COMPONENTS
•
•
•
•
•
•
•
•
Epimysium
Fasciculus
Endomysium
Perimysium
Sarcomere
Myofibril
Actin
Myosin

33. Functional Unit of the Muscle
 Typical muscle surrounded by connective tissue,
continuous with tendon, called epimysium
 Inside muscle are bundles of muscle fibers
surrounded by perimysium called fascicles
 Muscle fibers elongated cells up to 12 inches (30
centimeters) in length

34. Functional Unit of the Muscle
 Muscle fiber encased in connective tissue sheath
(endomysium); filled with cylinders (myofibrils)
endomysium
myofibrils
 Sarcomeres
 Myofibril made of protein threads arranged in
contractile units; two types of protein threads
Thick myofilaments made up of protein myosin
Thin ones made up of protein actin

35. Functional Unit of the Muscle
 Sarcomeres (cont'd)
 Actin and myosin
filaments arranged
in repeating units
(sarcomeres)
(sarcomeres
separated from
each other by dark
bands called Z lines
 Give striated
appearance to
skeletal muscle
 Each myofibril
made up of several
sarcomeres

36. ATP and Calcium
 Energy molecule adenosine
triphosphate (ATP) and calcium (Ca)
needed for contraction and
relaxation
 ATP provides energy to help myosin
heads form and break crossbridges
with actin
 When muscle relaxed, calcium stored
away from actin and myosin in
sarcoplasmic reticulum (SR)

37. Sarcoplasmic Reticulum (SR) vs.
Endoplasmic Reticulum (ER)
SR are found mainly in smooth
& skeletal muscles
While both have protein molecules in their cells, the
endoplasmic reticulum mainly synthesizes protein
molecules, while the sarcoplasmic reticulum (a type
of smooth ER) stores and pumps calcium ions. The
sarcoplasmic reticulum contains large stores of
calcium, which it sequesters and then releases when
the muscle cell is stimulated

38. Muscular System:
Neuromuscular Junction
Watch the Video of “Neuromuscular
Junction”
http://www.youtube.com/watch?v=vyQWGclkGWQ

39. Muscle Contraction
Step-by-Step

40. Muscular System:
Muscle Contraction
Watch the Video of “Muscle Contraction”
https://www.youtube.com/watch?v=WVuW560nRII

41. Muscle Contraction
Step-by-Step

42. Muscular Fuel
 Muscles, like all tissue, needs fuel in the form of
nutrients and oxygen to survive and function
 Body stores glycogen in the muscle, where it waits
muscle
to be converted to useable energy source
 When needed, glycogen converted to glucose
which releases energy

43. Muscular Fuel
 Muscles with very high demands store fat and use it
as energy
 Energy release causes heat production; this is why
production
strenuous/prolonged exercises can overheat our
bodies
 Higher demand muscles have richer blood supply to
carry oxygen to muscles giving those muscles a
darker color

44. Test Your Knowledge
Review 6 Questions
for Section 7-3

45. Smooth Muscle
 Also called visceral muscle, found in organs
(except heart), blood vessels (vasodilatation and
vasoconstriction), and bronchial airways
vasoconstriction
 Ability to expand and contract essential to internal
processes of body (digestion and regulation of
blood pressure)

46. Smooth Muscle
 During asthma attack,
smooth muscles in
airways of lungs
constrict, making it
difficult to get air into
and out of lungs
 Causes wheezing
sound

47. Smooth Muscle
 Special type of smooth
muscle (sphincter) found
sphincter
throughout digestive
system
 Donut-shaped muscles
act as doorways to let
materials in and out by
alternately contracting
and relaxing

48. Cardiac Muscle
 Forms walls of the heart
 Contraction of cardiac muscle
squeezes blood out of chambers
of the heart, causing blood to
circulate through the body
 Involuntary
 Fibers shorter; receive richer
supply of blood than any other
muscle in body

49. Cardiac Muscle
 Fibers connected by intercalated
discs, causing one fiber to
discs
contract and then pull next one
into contraction creating domino
effect; contraction occurs,
allowing blood to be squeezed out
of the heart and into the body
 Does not regenerate; damage
regenerate
often leads to tissue death
causing scarring of heart tissue;
scar tissue does not help muscles
of the heart to contract

50. Figure 7-11
Heart and intercalated discs.

51. Muscle Movements in Pairs
Pair off with a partner and perform various
muscle movements. Check his/her accuracy
Movements will show rotation, abduction,
adduction, extension and flexion of these
body parts:

52. Exam Chapters 6 and 7
Exam will be on Oct 29 at 9:30
•Multiple Choice
•Fill in the Blanks
•Short Essays (taken directly from the Short
Essays at end of Chap 6 and 7)
•Extra Credit: Read page 149 “Muscle Tone”