Lesson 6.1 Musculoskeletal System PDF

Lesson 6.1 THE MUSCULOSKELETAL SYSTEM ~~~ TOPICS COVERED IN THIS LESSON Components and Functions of the Musculoskeletal System Major Muscles of the Hu...

Lesson 6.1 THE MUSCULOSKELETAL SYSTEM ~~~ TOPICS COVERED IN THIS LESSON Components and Functions of the Musculoskeletal System Major Muscles of the Human Body © 2015 Thompson Educational Publishing, Inc. 1  Focussing Question ~~~ “What are the main components and functions of the musculoskeletal system?” © 2015 Thompson Educational Publishing, Inc. 2  The Musculoskeletal System The musculoskeletal system consists of bones, joints, and muscles that provide form, support, and stability to a body, thus giving humans (and many other animal species) the ability to move. © 2015 Thompson Educational Publishing, Inc. 3  Types of Muscle Tissue Below are diagrams and electron micrographs of each type of muscle tissue, differentiated by structure and function: (A)smooth muscle, (B) cardiac muscle, and (C) skeletal muscle. © 2015 Thompson Educational Publishing, Inc. 4  Smooth Muscles and Cardiac Muscles Muscle tissue refers to a collection of cells that shorten during contraction. Smooth Muscles. Surrounding the body’s internal organs, including the blood vessels, hair follicles, and the urinary, genital, and digestive tracts, are smooth muscles. Smooth muscle tissue contracts more slowly than skeletal muscles, but can remain contracted for longer periods of time. They are also involuntary. Cardiac Muscles. As the name suggests, cardiac muscles are found in only one place in the body—the heart. They are responsible for creating the action that pumps blood from the heart to the rest of the body. Cardiac muscles are involuntary muscles because they are not controlled © 2015 Thompson consciously, and are instead Educational Publishing, Inc. 5 directed to act by the autonomic nervous  Skeletal Muscles Skeletal Muscles. These muscles are the type of muscles that are attached to the bones (by tendons and other tissues). They are the most prevalent muscle type in the human body—they comprise 30 to 40 percent of human body weight. Skeletal muscles are “voluntary”—humans have conscious control over their skeletal muscles; that is, the brain can tell them what to do. Skeletal muscle tissue is referred to as striated, or striped, because of its appearance under a microscope as a series of alternating light and dark stripes. © 2015 Thompson Educational Publishing, Inc. 6  Support, Movement, Protection & Storage The musculoskeletal system supports the body, keeps it upright, allows movement, and protects vital organs. The skeleton also serves as the main storage system for calcium, phosphorus, and components of blood. The musculoskeletal system is made up of: The body’s bones, skeletal muscles, and connective tissue that binds them together. Skeletal muscle fibre connects to bones directly through tough tissue fibres, called tendons. © 2015 Thompson Educational Publishing, Inc. 7 The bones themselves are bound tightly  Types of Muscle Contraction There are three types of muscle contraction, as shown in the diagram (top to bottom): Concentric contraction (shortening) Eccentric contraction (lengthening) Isometric contraction © 2015 Thompson Educational Publishing, Inc. 8 (static)  How Skeletal Muscles Are Named Muscles are typically named after their action, location, shape, direction of the fibres, number of divisions/heads, or the points of attachment. © 2015 Thompson Educational Publishing, Inc. 9  Major Muscle Groups (Anterior) The major muscles on the front of the body include: The quadriceps group The rotator cuff group The abdominals , and The pectoral muscles © 2015 Thompson Educational Publishing, Inc. 10  Major Muscle Groups (Posterior) The major muscles on the back of the body include: The erector spinae group The rhomboids The gluteals (the “glutes”) The hamstring group and The calf muscles © 2015 Thompson Educational Publishing, Inc. 11  Agonist and Antagonist Muscle Pairs Muscles pull. They never push. Skeletal muscles are typically arranged as opposing pairs. The muscle primarily responsible for movement of a body part is referred to as the agonist muscle. The muscle that counteracts the agonist, lengthening when the agonist muscle contracts, is called the antagonist muscle. © 2015 Thompson Educational Publishing, Inc. 12  Opposing Muscles and Muscle Groups © 2015 Thompson Educational Publishing, Inc. 13