1. THE MUSCULAR SYSTEM
Mrs. Neistadt Biology

2. THE MUSCULAR SYSTEM

3. MUSCULAR SYSTEM
*There are 206
bones in the body
* There are
approximately 640
skeletal muscles in the
body.

4. *Three Types of Muscle
 *Muscles are classified according to their
structure and function.

5. *SMOOTH MUSCLE
*Involuntary Muscle
*Muscle of the internal organs:
(stomach, intestines, etc.)
*Not striated, or striped, 1 nucleus

6. *CARDIAC MUSCLE
*Involuntary
*Only in the heart muscle
*Contracts efficiently and
rhythmically
*Striped or Striated, with light
and dark bands and many nuclei

7. *SKELETAL MUSCLE
*Voluntary Muscle
*Attached to bones by
tendons
*When contracted, cause
the body to move

8. Skeletal Muscle Contraction
 *Most skeletal muscles are arranged in
opposing, or antagonistic pairs.

9. Muscle Fibers

10. *TWO TYPES OF MUSCLE
FIBERS:
Slow- Fast-
twitch twitch

11. *Slow-twitch muscle fibers
 *Slow-twitch muscle fibers have more
endurance than fast-twitch muscle
fibers.
 They contain myoglobin, a respiratory
molecule that stores oxygen and serves
as an oxygen reserve.

12. SLOW-TWITCH FIBERS

13. Fast-Twitch Muscle Fibers
 *Fast-twitch muscle fibers fatigue easily
but provide great strength for rapid,
short movements.
 They rely on anaerobic metabolism, which
causes a buildup of lactic acid.

14. FAST-TWITCH FIBERS

15. ENERGY FOR MUSCLES
*Muscle cells need energy to contract
*Muscle cells use cellular respiration to make
ATP (adenosine triphosphate)
* ATP = Energy (aerobic)
*If enough oxygen is not available, muscles
will rely on lactic acid fermentation for energy.
(anaerobic)

16. WHEN SOMETHING GOES
WRONG…
Muscular Dystrophy-
• An inherited disease that
affects the skeletal
muscles in the body.
• Eventually, the muscles
are destroyed and the
person may become
paralyzed.

17. REVIEW QUESTIONS:
W R I T E O N A S E PA R A T E PA P E R T O T U R N I N :
1. Compare and Contrast skeletal, smooth and cardiac muscle.
2. Explain why it is important for skeletal muscles to be found
antagonistic (opposite) pairs.
3. Explain why it is important that no muscle contains only slow-
twitch or only fast-twitch fibers.
4. When does a muscle require ATP?
5. Related to #4: Why does your body use energy even when you
are sleeping?