1. 12/4 have your wp #1 out to be checked in. Lecture on General muscles to microscopic muscle Building a muscle HW: Quiz on muscle names & wp #2. Finish coloring muscle sheets if not completed in class

2. B. Skeletal Muscle 1. Attached to bones by tendons 2. Cells are multinucleate & large a. Called muscle fibers due to long slender structure. 3. Striated – have visible banding of light and dark 4. Voluntary – subject to conscious control 5. Composition of skeletal muscle is: muscle fibers, connective tissue, blood vessels & nerves.

4. C. Smooth Muscle 1. Has no striations 2. Spindle-shaped cells 3. Single nucleus 4. Involuntary – no conscious control 5. Found mainly in the walls of hollow organs a. Controls your pupil!

6. D. Cardiac Muscle 1. Shares features w/ skeletal & smooth 2. Has striations but smaller cells than skeletal 3. Usually has a single nucleus like smooth but can SOMETIMES have a double nucleus. 4. Involuntary like smooth muscle 5. Found only in the heart

7. Cardiac Muscle

8. 1. The Organization of Skeletal Muscle. Skeletal muscle Fasicles (bundle of muscle cells (fibers)) Muscle cells (aka: muscle fibers) myofibril (a muscle cell organelle composed of…) sarcomeres (units w/i the myofibrils made of alternating…) myofilaments (protein chains either THICK (myosin) or THIN (actin)) Z lines (region of separation between sarcomeres)

10. E. Microscopic Skeletal Muscle & Contractions NOTE: As we discuss muscle contractions, we are only going to discuss skeletal muscle contraction.

11. 2. Micro-Anatomy of Skeletal Muscle a.Myofibril i. Bundles of myofilaments ii. Myofibrils are aligned to give distinct bands b. Sarcomere i. Contractile unit of a muscle fiber Figure 6.3b

12. c. Organization of the sarcomere i. Thick filaments = myosin filaments ii. Thin filaments = actin filaments iii. Both composed of the protein Figure 6.3c

13. d. Myosin filaments have cross-bridges i. Myosin and actin layer and overlap w/ exception of H zone ii. At rest, there is a H zone. When contracted this is closed Figure 6.3d H H

15. Muscle model build Use the coloring sheets to help you figure out all of the parts. The coloring sheets should be colored, you can do this in conjunction of creating your model.

16. HW Quiz on muscle naming Wp #2 on neuromuscular Junction & Sliding filament model. Finish coloring muscle ws

17. 12/8-9 Have your wp #2 & coloring muscle / parts of muscle worksheet out- check answers with each other Quiz on muscle names PPP on neuromuscular and sliding filament HW: WP #3-exercise & ws

18. Muscle control a. Skeletal muscles are directly connected to the nervous system by neuromuscular junctions. i. Impulses from the nerve cell controls the contractions ii. One nerve stimulates a few muscle cells or hundreds

19. Pg 293

20. c. At the neuromuscular junction i. The 2 cells never meet. ii. The gap between them is a synaptic cleft -filled with special interstitial fluid

21. Nerve Stimulus to Muscles Figure 6.5b

22. d. When a muscle contracts… i. Nerve releases acetylcholine (ACh) ii. ACh diffuses across the synaptic cleft & meets the… - sarcolemma: plasma membrane of the muscle cell. iii. ACh causes sodium (Na+) to rush in and potassium (K+) to rush out of the muscle cell –BUT more Na+ gets in than K+ gets out…

23. iv. This causes the muscle cell to change polarity passes the electrical current called Action Potential. e. Once begun this can not stop and the current travels over the entire sarcolemma (like dominos) i. the impulse moves & the muscle cell contracts

24. g. When the electrical pulse fires, the specialized sarcoplasmic reticulum (an organelle that covers the myofibril) releases calcium into the sarcomere. i.Ca+ allows actin and myosin to interact and the cross-bridge is created. h.The cell returns to a resting state when impulse ends i.The sodium/potassium pump (active transport) restores original levels of Na & K and the calcium is reabsorbed by the specialized endoplasmic reticulum

25. https://www.youtube.com/watch?v=7wM5_ aUn2qshttps://www.youtube.com/watch?v=7wM5_ aUn2qs

26. The sliding filament model a. Myosin and Actin cause the muscle to contract. b. Actin slides over the myosin c. Myosin forms a cross-bridge w/ actin. d. ATP changes the shape of the myosin cross-bridge - this pulls the actin filament towards the center of the sarcomere. -The crossbridge happens over and over until the contraction stops. e. The distance between the Z line decreases & H zone is minimized.

27. https://www.youtube.com/watch?v=Ct8Ab Zn_A8Ahttps://www.youtube.com/watch?v=Ct8Ab Zn_A8A

28. actin

29. Rest of class & HW Fill in the neuromuscular table Fill in the neuromuscular worksheet. You may work in pairs of your choice. HW: WP #3, table, FITB & color WS

30. 12/10-11 1. Have your WP #3 out and neuromuscular junction ws 2. Presentation 3. Fatigue activity HW: Dissection Prep & activity if you do not finish.

31. Contraction of a Skeletal Muscle Muscle fiber contraction is “all or none” Within a skeletal muscle, not all fibers may be stimulated during the same interval Different combinations of muscle fiber contractions may give differing responses Graded responses – different degrees of skeletal muscle shortening

32. Types of Graded Responses Twitch –Single, brief contraction –Not a normal muscle function Tetanus (summing of contractions) & Unfused/incomplete tetanus –One contraction is immediately followed by another w/o returning to a resting state –The effects are added

33. Types of Graded Responses Fused (complete) tetanus –No relaxation between contractions –The result is a sustained muscle contraction Figure 6.9c–d

34. Muscle Response Muscle force depends upon the number of fibers stimulated More fibers = more power Can contract until cells run out of energy

35. Energy for Muscle Contraction First- used stored ATP for energy –Only 4-6 seconds worth of ATP is stored by muscles! THEN other pathways must be utilized to produce ATP

36. SECOND- Direct phosphorylation –Muscle cells use creatine phosphate (CP), a high- energy molecule –CP transfers energy to ADP, to regenerate ATP –CP supplies are exhausted in about 20 seconds

37. THIRD- Aerobic Respiration –Occur in the mitochondria WITH OXYGEN –Glucose is broken down to carbon dioxide and water, releasing LOTS OF ATP –This is kinda slow…

38. FOURTH- Anaerobic glycolysis –breaks down glucose without oxygen –Glucose is broken down and produces only few ATP & converted to lactic acid –Not efficient but fast Lactic acid produces muscle fatigue Figure 6.10c

39. Types of Muscle Contractions Isotonic contractions –Myofilaments are able to slide past each other during contractions –The muscle shortens Isometric contractions –Tension in the muscles increases –The muscle is unable to shorten

40. Effects of Exercise on Muscle Results of increased muscle use –Increase in muscle size –Increase in muscle strength –Increase in muscle efficiency –Muscle becomes more fatigue resistant

41. Exercise & Muscles 1. Use it or lose it! a.Muscle will quickly waste away if it is not used! 2. Types of Exercise a. Aerobic exercise- increase strength, flexibility, & resilience to fatigue. i. Increase blood supply, individual cells create more mitochondria to convert food to ATP

42. 3. Anaerobic- force more muscle cells to contract w/ as much force as possible. a. Increases muscle size b/c individual muscle cells become larger by making more contractile filaments b. The cells do not multiply! http://www.youtube.com/watch?v=kg6d ovLasMI How big can I get? http://www.youtube.com/watch?v=dC hhzNGHgnA http://www.youtube.com/watch?v=dC hhzNGHgnA

43. Muscle Tone Some fibers are contracted even in a relaxed muscle Different fibers contract at different times to provide muscle tone The process of stimulating various fibers is under involuntary control 1. At any given time some muscle cells, in each muscle, are contracting. 2. Muscle tone is why when resting you can still sit up. 3. Sleeping is the only time your muscles are completely relaxed.

44. Muscle Fatigue and Oxygen Debt When a muscle is fatigued, it is unable to contract The common reason for muscle fatigue is oxygen debt –Oxygen is required to get rid of accumulated lactic acid Increasing acidity (from lactic acid) and lack of ATP causes the muscle to contract less

45. 4. Muscle Fatigue: Muscles become fatigued when cells are unable to contract even if still being stimulated. a. Without rest active muscles tire and contractions begin to weaken. b. Can stop working altogether (collapse) which is thought to be due to oxygen depletion

46. Fatigue Activity! Follow the directions Ask if you need help. Finish in class today…if you run out of time then finish for HW. Unit test is last day before break There will be jeopardy HW: Dissection prep & finish the Lab… Also I recommend watching crash course muscles.

47. crash course muscular system http://www.youtube.com/watch?v=jqy0i1K XUO4http://www.youtube.com/watch?v=jqy0i1K XUO4