Mader: Understanding ② The McG ysiology, Fifth Edition The Focus is Understanding Students develop a working knowledge of anatomy and physiology based upon conceptual understanding. Clinical Applications broaden students'horizons beyond the core principles. Self-confidence increases as students master medical terminology and key concepts Art Program Art presents and reinforces the dynamic processes within the human bod The Muscular System Dynamic Photos give students a closer look inside the wonders of the human body through the technology of scanning electron micrographs N visual focus Visual Focus illustrates difficult concepts that relate structure to function, using a step-by New and revised art oncise labeling methodology that keeps students from getting bogged down with excessive detail The most beautiful thing we can experience as ausmus is the mysterious. It is the source of all true art and scienceMader: Understanding Human Anatomy & Physiology, Fifth Edition Front Matter Preface © The McGraw−Hill Companies, 2004 xv • Students develop a working knowledge of anatomy and physiology based upon conceptual understanding. • Clinical Applications broaden students’ horizons beyond the core principles. • Self-confidence increases as students master medical terminology and key concepts. Art Program Art presents and reinforces the dynamic processes within the human body. chapter The Muscular System Scanning electron micrograph of motor neurons terminating at muscle fibers. A muscle fiber receives the stimulus to contract at a neuromuscular junction. chapter outline & learning objectives After you have studied this chapter, you should be able to: 7.1 Functions and Types of Muscles (p. 114) ■ Distinguish between the three types of muscles, and tell where they are located in the body. ■ Describe the connective tissues of a skeletal muscle. ■ Name and discuss five functions of skeletal muscles. 7.2 Microscopic Anatomy and Contraction of Skeletal Muscle (p. 116) ■ Name the components of a skeletal muscle fiber, and describe the function of each. ■ Explain how skeletal muscle fibers are innervated and how they contract. ■ Describe how ATP is made available for muscle contraction. 7.3 Muscle Responses (p. 122) ■ Contrast the responses of a muscle fiber and whole muscle in the laboratory with their responses in the body. ■ Contrast slow-twitch and fast-twitch muscle fibers. 7.4 Skeletal Muscles of the Body (p. 124) ■ Discuss how muscles work together to achieve the movement of a bone. ■ Give examples to show how muscles are named. ■ Describe the locations and actions of the major skeletal muscles of each body region. 7.5 Effects of Aging (p. 134) ■ Describe the anatomical and physiological changes that occur in the muscular system as we age. 7.6 Homeostasis (p. 136) ■ Describe how the muscular system works w other systems of the body to maintain homeostasis. ■ Describe some common muscle disorders a some of the serious diseases that can affec muscles. Visual Focus Anatomy of a Muscle Fiber (p. 117) Medical Focus Benefits of Exercise (p. 135) 113 Dynamic Photos give students a closer look inside the wonders of the human body through the technology of scanning electron micrographs. Visual Focus illustrates difficult concepts that relate structure to function, using a step-by￾step process. New and Revised Art focuses on the main concepts by using concise labeling methodology that keeps students from getting bogged down with excessive detail. Chapter 7 The Muscular System 117 Figure 7.3 Anatomy of a muscle fiber. A muscle fiber contains many myofibrils with the components shown. A myofibril has many sarcomeres that contain myosin and actin filaments whose arrangement gives rise to the striations so characteristic of skeletal muscle. Muscle contraction occurs when sarcomeres contract and actin filaments slide past myosin filaments. bundle of muscle fibers muscle fiber T tubules nucleus sarcoplasm sarcolemma cross-bridge myosin actin sarcoplasmic reticulum calcium storage sites one sarcomere Z line Z line H zone Z line Muscle fiber has many myofibrils. skeletal muscle fiber one myofibril A band I band Myofibril has many sarcomeres. Sarcomere is relaxed. Sarcomere is contracted. Muscles of the Abdominal Wall The abdominal wall has no bony reinforcement (Fig. 7.14). The wall is strengthened by four pairs of muscles that run at angles to one another. The external and internal obliques and the transversus abdominis occur laterally, but the fasciae of these muscle pairs meet at the midline of the body, forming a tendinous area called the linea alba. The rectus abdominis is fi i l di l i f l Muscles of the Shoulder Muscles of the shoulder are shown in Figures 7.14 and 7.15. They are also listed in Table 7.4 on page 130. The muscles of the shoulder attach the scapula to the thorax and move the scapula; they also attach the humerus to the scapula and move the arm. Figure 7.15 Muscles of the posterior shoulder. The right trapezius is removed to show deep muscles that move the scapula and the rotator cuff muscles. trapezius deltoid latissimus dorsi rotator cuff muscles “The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.” – Albert Einstein