1.  Name the following movements: ◦ Increasing angle of joint (ex. Straightening arm) ◦ Moving around longitudinal axis: ◦ Moving a limb away from midline of body:

3.  Muscle  Fascicle (Muscle bundles)  Muscle fibers (muscle cells)  Myofibrils  Myofilaments (thick and thin)

5.  Cell membrane of skeletal muscle cells

6.  1 muscle fiber = many myofibrils  1 myofibril = many thick and thin filaments  The thick and thin filaments form the smallest functional unit of muscle the sarcomere

7.  Made of proteins ◦ Structural: make up the structural framework of muscles ◦ Contractile: involved in the process of contraction ◦ Regulatory: not part of contraction, but they regulate it

8.  Actin (thin filament) has binding sites for myosin

9.  1950s – scientists observed that the length of thick and thin filaments stayed the same during muscle contraction  This led to the Sliding Filament Theory: ◦ During muscle contraction, the thick and thin filaments do not shorten, but slide on one another which results in the shortening of the sarcomere and the entire muscle

10.  1. Myosin head binds to ATP  2. Myosin head gets energized

11.  3. Crossbridge forms between myosin head and actin

12.  4. Power stroke causes filaments to slide

13.  5. Another ATP molecule binds to myosin head causing it to release from actin and return to original position

14.  http://www.youtube.com/watch?v=Ct8AbZn_ A8A http://www.youtube.com/watch?v=Ct8AbZn_ A8A

15.  How is the sliding filament theory similar to these doors?

16.  Troponin and Tropomyosin (regulatory proteins) depend on Calcium ions  Troponin: has binding site for calcium ions  Tropomyosin: covers binding site on actin

17.  What would happen if there are no Calcium ions present?

18.  6 most important chemicals (molecules): ◦ Myosin, actin, tropomyosin, troponin, ATP, Calcium

19.  Kahoot.it