1. Muscular System
Chapter 8

3. The 3 Muscle Types The job of all muscles is to contract
The 3 Muscle Types Are:
Skeletal Muscle
Cardiac Muscle
Smooth Muscle

4. Skeletal Muscle Cigar Shaped Multinucleated Striated Voluntary
Can Be Involuntary When Reflexes Are Involved
Very Strong and Fast But Needs Rest
Most Attached to Bone

5. Skeletal Muscle Cell

6. Cardiac Muscle

7. Smooth Muscle
Long thin nuclei and no striations

8. How are Muscles Structured?
Muscle Cells have a plasma membrane called a Sarcolemma.
The muscle fiber is enclosed in Endomysieum. (Endo= , Mys= )
Many Muscle fibers bound together make a Fascicle.
The Fascicle is wrapped in a membrane called the Perimysieum (Peri= ).

9. Muscle Structure Continued
Many fascicles are wrapped together by an Epimysium. (Epi= )
Epimysia attach to tendons

10. Skeletal Muscle

11. Inside the Muscle Fiber

12. What is the major Organelle of the Muscle Cell?
Myofibril(s)=Working unit of the muscle cell. Made of Subunits called sarcomeres.
Give muscles the striped or striated appearance
The light band = I-band
The dark band = A-band
Between the I-bands = Z-line
Between the A-bands = H-zone
Match the
Terms

13. Mechanism of muscle contraction
The above micrographs show that the sarcomere gets shorter when the muscle contracts
The light (I) bands become shorter
The dark bands (A) bands stay the same length

14. Take a long deep breath, its not that bad.
And remember a bicycle cannot stand alone, because it is two tired.
Now lets go on.
But lets first watch this short video clip.
Overview of the
Job of the Bands

15. So how do these bands work?
The myofibrils are surrounded by the sarcoplasmic reticulum, a specialized form of smooth endoplasmic reticulum that releases calcium.
They are made of bands of
Actin (the thin filaments) that make up the I-bands
Myosin (the thick filaments) that make up the A-bands

16. How does ACh stimulate the muscle?
ACh causes the sarcolema to release Calcium (Ca+)
Ca+ binds to the actin causing it to change shape.
Myosin finds actin’s new shape attractive and grabs hold.

17. What happens after the Myosin grabs hold?
Myosin’s head snap towards the H-band of the sarcomere.
ATP releases and rearranges the myosin
Only some myosin heads move at one time.
Description of
Muscle movement

18. How does the muscle relax?
When the action potential ends:
Sarcomere absorb Ca+
ATP releases myosin heads
Actin takes on its former and less attractive shape.
Muscle Cells can relax
Myofilament
Contraction

19. It is important to remember the heirarchy
myosin
myofibrils
fasicles
myofilaments
actin

20. It is important to remember the heirarchy
fasicles
myofibrils
myofilaments
actin
myosin

21. muscle fiber
myofilament
myofibrils
epimysium
muscle
sarcomere

22. myofilament
muscle
sarcomere
epimysium
myofibrils
muscle fiber

23. How do muscles work together?
Prime Mover: Major muscle doing the bulk of the work contracting.
Synergist: Group of muscles working together to contract.
Antagonist: Muscle that works against the prime mover and or synergists.

24. To exercise the:
Quadriceps

25. To exercise the:
Gastronemius

26. To exercise the:
Hamstring Group
Includes the bicepts femoris

27. Exercise the:
Trapezius

28. Exercise for:
Deltoid

29. Exercise For:
Gluteus Maximus

30. Exercises for:
Oblique

31. Exercises for:
Rectus Abdominus

32. Exercise for:
Pectoralis Major
Push up: Works Pecs on
The Up-Motion

33. Exercises for:
Bicep