1. The Anatomy of Skeletal Muscle
Muscle fiber looking outward:
Perimysium
______________________
Epimysium
____________________
Muscle fiber looking inward:
Endomysium
_______________________________ ______________
_______________
Contains cytoplasm (sarcoplasm)
_____________
Contain actin and myosin
Contains myosin and actin
Muscle fibre
Perimysium
Epimysium
Endomysium
Muscle belly
Tendon
©Thompson Educational Publishing, Inc All material is copyright protected. It is illegal to copy any of this material.
This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

3. Properties of Muscle Fiber
Contractibility
Refers to muscle shortening in length
Elasticity
Refers to muscle stretching and returning to normal position
Extensibility
___________________________________
Conductivity
©Thompson Educational Publishing, Inc All material is copyright protected. It is illegal to copy any of this material.
This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

4. _____________________
Axon
Neurotransmitter acetylcholine (Ach)
Sarcolemma
Axon Terminal
Synaptic Cleft
Receptor
©Thompson Educational Publishing, Inc All material is copyright protected. It is illegal to copy any of this material.
This material may be used only in a course of study in which Exercise Science: An Introduction to Health and Physical Education (Temertzoglou/Challen) is the required textbook.

5. Structure of Skeletal muscles
The myofibril consists of protein chains called ________________
Myofilaments have a symmetrical, alternating pattern of thick and thin elements.

6. Skeletal Muscle Myosin
_____________________
consists of a large number of bundled myosin molecules aligned in overlapping arrays.

7. Skeletal Muscle Actin __________________________
made up of two helically intertwined chains of G-actin (globular actin) units.
Other proteins that bind to the actin molecules:
_________________
The Troponin complex→ made up of three members

11. The Steps of Muscle Contraction: The Sliding Filament Theory

12. Key events that must take place before the contraction of a muscle fiber begins:
_______________________________________ _______________________________________
The calcium ions ____________________which causes the troponin-tropomyosin complexes to move away from the myosin binding sites on actin.
Once this happens contraction can begin.
The process is similar to rowing, each myosin head rows forward using the actin as a base to pull from.

13. Step 1: ATP hydrolysis by Myosin
__________________________________ __________________________________
ATP is hydrolyzed into ADP freeing up a Phosphate molecule, this energizes the myosin head.

14. Step 2: Myosin Attaches to Actin
Myosin attaches to the myosin binding site on actin and releases the free phosphate group
__________________ __________________ __________________

15. Step 3: The Powerstroke
Phosphate release by myosin triggers the actual power contraction stroke
_________________________________
Myosin head rotates and _____________
As the head rotates it moves in a ratchet like motion and pulls the thin filaments closer to the center of the M line of the sarcomere

17. Step 4: Detachment of Myosin
When the ratchet motion is over the myosin awaits another ATP so it can be released from the actin binding site
__________________________________ __________________________________
If not the Myosin remains locked in place and the muscle remains locked up as well this is called “__________”

19. END RESULTS FOR SARCOMERE
Z lines move closer together
________________
I band shortens
___________________
A band stays the same

20. Summary Points ________________________________
The movement of myosin and actin is like rowers moving across water
Myosin heads will keep binding with actin sites until the ATP runs out or the Calcium levels decrease
__________________________________ __________________________________