1. The Muscular System

2. 3 kinds of muscle All have cells specialized to contract for movement

3. Skeletal muscle moves bones Long, thin cells called fibers More than one nucleus per cell Striated voluntary

4. Smooth muscle Found in walls of hollow organs & blood vessels Smaller cells, not striated One nucleus involuntary

5. Cardiac muscle Found in the heart Contracts without signals from nervous system Involuntary Striated multinucleated

6. The Muscular System (skeletal muscle) Structure of a muscle: a bundle of muscle fibers

7. Functions of muscles Over 600 muscles produce the varied movements of the body Origin: side of muscle that attaches to the non-moving bone Insertion: attaches to the moving bone Joints are like levers and muscles provide force whereas the mass of the bone is the resistance

8. Functions of muscles

9. Muscles work together Antagonistic pairs One contracts while the other relaxes (reciprocal innervation prevents nervous signals to the relaxing muscle so that both cannot contract at the same time) Each responsible for an opposing movement Example: biceps/triceps. Can you think of any others?

10. Muscles work together Synergistic groups: contraction of one adds force or stabilizes the movement of the others

11. 2 functional types of skeletal muscle fibers “slow” or “red” fibers Myoglobin pigment binds oxygen More blood vessels deliver more oxygen More mitochondria- lots of ATP, sustain slow contractions over long periods of time “fast” or “white” fibers Less myoglobin, blood vessels, mitochondria Use lactic acid fermentation to make smaller amts. of ATP Faster, more powerful contractions can’t be sustained over long periods of time

12. Fast & slow fibers Muscles have a combination of both, depending on their job and location, they may have more of one or the other Find a slow fiber and a fast fiber…

13. Athletes Percentage of fast and slow fibers is genetically determined Athletes can train to increase the size and power of fast fibers or the endurance and stamina of slow fibers (especially In the legs)

14. Discuss… In turkey, the dark meat is muscle with lots of slow fibers, light meat is muscle with lots of fast fibers. Which parts of the turkey are light & dark? Think about a turkey’s life style. See if this makes sense.

15. Physiology: T 11.8.11 Word of the Day: striation (skeletal and cardiac muscle fibers have striations) TCB Study guide online and some paper copies GOALS/AGENDA Complete muscle basics (5 min) Lab- musclemania

16. Physiology: T 10.12 Lab: musclemania! Follow instructions and fill in questions on lab sheet Clean up- return slides to case and microscopes to cart

17. Musclemania View prepared slides of muscle tissue and draw what you see Create a wet mount of skeletal muscle tissue and view under the microscope Complete musclemania lab sheet

18. Musclemania part 2 Safety concerns: biostain, raw meat, sharp tools Cleanup: rinse all materials and return to side bench Procedure: watch demo, keep methylene blue and water containers on side bench

19. Physiology: W 11.9 Word of the Day: sarcomere (the contractile unit of a muscle is a sarcomere) TCB Quiz corrections today GOALS/AGENDA Complete musclemania (20 min) Introduction to how muscles contract

20. How Muscles Contract A muscle contracts when individual cells within it shorten Basic unit of contraction= sarcomere Contractile proteins- actin (thin filaments) & myosin (thick filaments)

21. How muscles contract When the sarcomere contracts it gets shorter but the filaments do not change in length. How is that possible?

22. Contracting filament

23. Physiology: Th 11.10 Word of the day: power stroke (a muscle contraction involves a series of power strokes by the myosin heads) TCB Don’t forget to email me! Continued review opportunities Next week GOALS/AGENDA Quick look at study guide Period 1 complete muscle contraction notes Muscle contraction skits (teams. For a grade)

24. Muscle Contraction Skits Create a skit showing the actions of sarcomeres during a muscle contraction 60 seconds (no more) No speaking allowed (sound effects ok) Props OK, check w/ me before using something from the classroom No written words, symbols/drawings OK Include actin, myosin, cross-bridges, Calcium, ATP Everyone must be in it

25. Watching the skits Critique! –Did it help you understand sarcomere contraction? (yes, no, sort of) –Was it creative? (yes, no, sort of) –Did you know what/who the actin, myosin, calcium and ATP were? (yes, no, sort of)