1. End Show Slide 1 of 37 Copyright Pearson Prentice Hall 36–2 The Muscular System

2. End Show 36–2 The Muscular System Slide 2 of 37 Copyright Pearson Prentice Hall Muscles The function of the muscular system is movement. More than 40% of the mass of the average human body is muscle.

3. End Show 36–2 The Muscular System Slide 3 of 37 Copyright Pearson Prentice Hall Types of Muscle Tissue There are three different types of muscle tissue: skeletal smooth cardiac

4. End Show 36–2 The Muscular System Slide 4 of 37 Copyright Pearson Prentice Hall Types of Muscle Tissue Skeletal Muscles Skeletal muscles: are usually attached to bones. are responsible for voluntary movements. are sometimes called striated muscles, meaning they appear “striped”.

5. End Show 36–2 The Muscular System Slide 5 of 37 Copyright Pearson Prentice Hall Types of Muscle Tissue Smooth Muscles Smooth muscles: are usually not under voluntary control = involuntary. are spindle-shaped. are not striated. are found in many internal organs and blood vessels.

6. End Show 36–2 The Muscular System Slide 6 of 37 Copyright Pearson Prentice Hall Types of Muscle Tissue Cardiac Muscle Cardiac muscle: is only found in the heart. is striated. is involuntary. Cells are connected to each other

7. End Show 36–2 The Muscular System Slide 7 of 37 Copyright Pearson Prentice Hall Muscle Contraction The fibers in skeletal muscles are composed of smaller structures called myofibrils. Each myofibril has smaller structures called filaments. Thick filaments = myosin. Thin filaments = actin.

8. End Show 36–2 The Muscular System Slide 8 of 37 Copyright Pearson Prentice Hall Muscle Contraction Skeletal muscle Bundle of muscle fibers Muscle fiber (cell) Myofibril Z line Sarcomere Myosin Actin

9. End Show 36–2 The Muscular System Slide 9 of 37 Copyright Pearson Prentice Hall Muscle Contraction A muscle contracts when the thin filaments in the muscle fiber slide over the thick filaments. This process is called the sliding filament model of muscle contraction.

10. End Show Slide 10 of 37 36–2 The Muscular System Copyright Pearson Prentice Hall Muscle Contraction During muscle contraction, the actin filaments slide over the myosin filaments, making the muscle shorter:

11. End Show 36–2 The Muscular System Slide 11 of 37 Copyright Pearson Prentice Hall Control of Muscle Contraction The energy for muscle contraction is supplied by ATP. Impulses from motor neurons control the contraction of skeletal muscle fibers.

12. End Show 36–2 The Muscular System Slide 12 of 37 Copyright Pearson Prentice Hall How Muscles and Bones Interact Skeletal muscles are joined to bones by tendons. Tendons pull on the bones so they work like levers. The joint functions as a fulcrum. The muscles provide the force to move the lever.

13. End Show 36–2 The Muscular System Slide 13 of 37 Copyright Pearson Prentice Hall How Muscles and Bones Interact Opposing Muscles Contract and Relax

14. End Show 36–2 The Muscular System Slide 14 of 37 Copyright Pearson Prentice Hall How Muscles and Bones Interact Opposing Muscles Contract and Relax

15. End Show 36–2 The Muscular System Slide 15 of 37 Copyright Pearson Prentice Hall Exercise and Health Regular exercise is important in maintaining muscular strength and flexibility.

16. End Show 36–2 The Muscular System Slide 16 of 37 Copyright Pearson Prentice Hall Exercise and Health Aerobic exercises help the body’s systems to become more efficient. Resistance exercises increase muscle size and strength.

17. End Show 36–2 The Muscular System Slide 17 of 37 Copyright Pearson Prentice Hall

18. End Show Slide 18 of 37 Copyright Pearson Prentice Hall 36–2 Skeletal muscles are joined to bones by tough connective tissue called a.ligaments. b.tendons. c.filaments. d.bursae.

19. End Show Slide 19 of 37 Copyright Pearson Prentice Hall 36–2 Muscle cells that are large, have many nuclei, and striations are a.skeletal muscle cells. b.smooth muscle cells. c.cardiac muscle cells. d.involuntary muscle cells.

20. End Show Slide 20 of 37 Copyright Pearson Prentice Hall 36–2 Muscle that is found in the walls of blood vessels and intestines is a.skeletal muscle. b.smooth muscle. c.cardiac muscle. d.striated muscle.

21. End Show Slide 21 of 37 Copyright Pearson Prentice Hall 36–2 The filaments found in skeletal muscle cells are a.actin and myosin b.myosin and myofibrils c.actin and Z lines d.actin and sarcomeres

22. End Show Slide 22 of 37 Copyright Pearson Prentice Hall 36–2 The type of muscle found only in the heart is a.skeletal muscle. b.striated muscle. c.cardiac muscle. d.smooth muscle.