Muscular+SystemGMS

1. What are the three types of muscles in the body and what is the function of each? Smooth Muscle - contracts muscles. invountary contraction Cardiac Muscle - forms the heart wall. involuntary contraction Skeletal muscle - they make up the skeletal muscles attached to the skeleton voluntary muscle 2. How do skeletal muscles work together to cause the bones to move? Muscle contraction acconts for movements of the eyes, facial expressions and breathing. 3. Insert an image of the major muscles in the body like the one on page 231. You will need to know the location and function of the following (write the function next to the name -- see page 231) Pectoralis major - brings arm forward and across the chest Deltoid - brings arm away from the side of body moves arm up and down in front trapezius - rasies scapula as when shrugging shoulders pulls head backward biceps brachii - bends forearm at elbow triceps brachii - straightens forearm at ellbow External oblique - compresses abdomen rotation of trunk latissimus dorsi - brings arm down and backward behind the body gluteus maximus - extends thigh back quardriceps femoris - sreaightens leg at knee, raises thigh gastrocnemius - turns foot downward as when standing on toes; bends leg at knee
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4. Define myofibrils, sarcomeres, myosin, actin Myofibrils - contractile portions of the muscle fibers sacromeres - fibers firmed by the placement of myofilaments within units of myofibrils. Myosin - thick filimant made up of protein in sarcomeres Actin - thin filamints made up of a protein in sarcomeres 5. Describe the structure of a sarcomere's thick and thin filaments. Thick filament - composed of several hundred molecules of the protein myosin. Each myosin is shaped like a golf club. thin filament - consits of two intertwining strands of the protein actin.

6. Describe the sliding filament model and insert image (How does the sarcomere contract?) The sarcomere shortens causing contraction ATP supplies the energy for muscle contraction myosin are the filaments that do the work they break down ATP and their cross bridges pull the actin filaments toward the center of sarcomere ||