Skeletal System Review Sponge

1. Skeletal System Review Sponge • Daily Objective: SWBAT compare and contrast the 3 types of muscles and demonstrate accurate knowledge of the skeletal system Skeletal System Review Sponge (complete in your composition notebook and record the entry) • Write the daily objective • Describe how the movement of a hinge joint differs from the movement of a ball-and-socket joint.

2. Table of Contents 10/31 Skeletal System Review sponge 42ish Intro to Muscular System notes 42ish Types of Muscle Organizer 44ish Exit ticket (time permitting) 45ish

3. Homework Reminder • Week 13 Online homework due SUNDAY 11/4 by 11:59pm • Science Fair Research Papers due TODAY • Wednesday 11/7 next session of the “Health Science Speaker Series”

4. The Muscular System • Muscles are responsible for all types of body movement • Three basic muscle types are found in the body I. Skeletal muscle II. Smooth muscle III. Cardiac muscle

5. Characteristics of Muscles • Skeletal and smooth muscle cells are elongated (muscle cell = muscle fiber) • Muscles contract due to the movement of microfilaments • All muscles share some terminology • Prefixes myo and mys refer to “muscle” • Prefix sarco refers to “flesh”

6. Comparison of Skeletal, Cardiac, and Smooth Muscles Table 6.1 (1 of 2)

7. Comparison of Skeletal, Cardiac, and Smooth Muscles Table 6.1 (2 of 2)

8. I. Skeletal Muscle Characteristics • Most are attached by tendons to bones • Cells are multinucleate • Striated—have visible banding • Voluntary—subject to conscious control

9. Connective Tissue Wrappings of Skeletal Muscle • Cells are surrounded and bundled by connective tissue • Endomysium—encloses a single muscle fiber • Perimysium—wraps around a fascicle (bundle) of muscle fibers • Epimysium—covers the entire skeletal muscle • Fascia—on the outside of the epimysium

10. Connective Tissue Wrappings of Skeletal Muscle Figure 6.1

11. Skeletal Muscle Attachments • Epimysium blends into a connective tissue attachment • Tendons—cord-like structures • Mostly collagen fibers • Often cross a joint due to toughness and small size

12. Skeletal Muscle Attachments • Sites of muscle attachment • Bones • Cartilages • Connective tissue coverings

13. Skeletal Muscle Functions • Produce movement • Maintain posture • Stabilize joints • Generate heat

14. II. Smooth Muscle Characteristics • Lacks striations • Spindle-shaped cells • Single nucleus • Involuntary—no conscious control • Found mainly in the walls of hollow organs

15. Smooth Muscle Characteristics Figure 6.2a

16. III. Cardiac Muscle Characteristics • Striations • Usually has a single nucleus • Branching cells • Joined to another muscle cell at an intercalated disc • Involuntary • Found only in the heart

17. Cardiac Muscle Characteristics Figure 6.2b

18. Muscle Graphic Organizer Word Bank: Multinucleated Uninucleated Striations No striations Epimysium Perimysium Endomysium Voluntary Involuntary Slow contraction Fast contraction Rhythmic contraction Moves

19. Skeletal System Review

20. Skeletal System Review

21. Skeletal System Review

22. Skeletal System Review

23. Muscular System Exit Ticket • Please complete in your composition notebook and record the entry in your table of contents • How is skeletal muscle involved in homeostasis? • Describe the difference between the endomysium and perimysium. • Describe the difference in shape between cardiac muscle and smooth muscle.

24. Microscopic Anatomy of Skeletal Muscle • Sarcolemma—specialized plasma membrane • Myofibrils—long organelles inside muscle cell • Sarcoplasmic reticulum—specialized smooth endoplasmic reticulum

25. Microscopic Anatomy of Skeletal Muscle Figure 6.3a

26. Microscopic Anatomy of Skeletal Muscle • Myofibrils are aligned to give distinct bands • I band = light band • Contains only thin filaments • A band = dark band • Contains the entire length of the thick filaments

27. Microscopic Anatomy of Skeletal Muscle Figure 6.3b

28. Microscopic Anatomy of Skeletal Muscle • Sarcomere—contractile unit of a muscle fiber • Organization of the sarcomere • Myofilaments • Thick filaments = myosin filaments • Thin filaments = actin filaments

29. Microscopic Anatomy of Skeletal Muscle • Thick filaments = myosin filaments • Composed of the protein myosin • Has ATPase enzymes • Myosin filaments have heads (extensions, or cross bridges) • Myosin and actin overlap somewhat • Thin filaments = actin filaments • Composed of the protein actin • Anchored to the Z disc

30. Microscopic Anatomy of Skeletal Muscle Figure 6.3c

31. Microscopic Anatomy of Skeletal Muscle • At rest, there is a bare zone that lacks actin filaments called the H zone • Sarcoplasmic reticulum (SR) • Stores and releases calcium • Surrounds the myofibril

32. Microscopic Anatomy of Skeletal Muscle Figure 6.3d

33. Stimulation and Contraction of Single Skeletal Muscle Cells • Excitability (also called responsiveness or irritability)—ability to receive and respond to a stimulus • Contractility—ability to shorten when an adequate stimulus is received • Extensibility—ability of muscle cells to be stretched • Elasticity—ability to recoil and resume resting length after stretching

34. The Nerve Stimulus and Action Potential • Skeletal muscles must be stimulated by a motor neuron (nerve cell) to contract • Motor unit—one motor neuron and all the skeletal muscle cells stimulated by that neuron

35. The Nerve Stimulus and Action Potential Figure 6.4a

36. The Nerve Stimulus and Action Potential Figure 6.4b

37. The Nerve Stimulus and Action Potential • Neuromuscular junction • Association site of axon terminal of the motor neuron and muscle

38. The Nerve Stimulus and Action Potential Figure 6.5a

39. The Nerve Stimulus and Action Potential • Synaptic cleft • Gap between nerve and muscle • Nerve and muscle do not make contact • Area between nerve and muscle is filled with interstitial fluid

40. The Nerve Stimulus and Action Potential Figure 6.5b

41. Transmission of Nerve Impulse to Muscle • Neurotransmitter—chemical released by nerve upon arrival of nerve impulse • The neurotransmitter for skeletal muscle is acetylcholine (ACh) • Acetylcholine attaches to receptors on the sarcolemma • Sarcolemma becomes permeable to sodium (Na+)

42. Transmission of Nerve Impulse to Muscle Figure 6.5c

43. Transmission of Nerve Impulse to Muscle • Sodium rushes into the cell generating an action potential • Once started, muscle contraction cannot be stopped

44. Transmission of Nerve Impulse to Muscle Figure 6.6

45. The Sliding Filament Theory of Muscle Contraction • Activation by nerve causes myosin heads (cross bridges) to attach to binding sites on the thin filament • Myosin heads then bind to the next site of the thin filament and pull them toward the center of the sarcomere • This continued action causes a sliding of the myosin along the actin • The result is that the muscle is shortened (contracted)

46. The Sliding Filament Theory of Muscle Contraction Figure 6.7a–b

47. The Sliding Filament Theory Figure 6.8a

48. The Sliding Filament Theory Figure 6.8b

49. The Sliding Filament Theory Figure 6.8c