1. T HE M USCULAR S YSTEM

2. T YPES OF M USCLE T ISSUE Three types of Muscle Tissue: Skeletal Smooth Cardia Each type of muscle tissue is specialiazed for a specific function

3. S KELETAL M USCLE Usually attached to bone Responsible for VOLUNTARY movement and often controlled by the CNS Appears to have alternating light and darks bands (sometimes called striated muscle)

4. S TRUCTURE OF S KELETAL M USCLE Skeletal muscles are bundles of muscle fibers Muscle fibers composed of myofibrils Myofibrils contains thin filaments (ACTIN) and thick filaments (MYOSIN)

5. S MOOTH M USCLE INVOLUNTARY muscle (not under conscious control) Found in the walls of hollow structures (stomach, blood vessels, and intestines) One nucleus and NOT striated

6. C ARDIAC M USCLE Found ONLY in the HEART INVOLUNTARY muscle

7. M USCLE C ONTRACTION Myofibrils are composed of ACTIN and MYOSIN Thick filament: Myosin Thin filament: Actin Arranged in units called sarcomeres Separated by regions called Z lines

8. M USCLE C ONTRACTION : T HE S LIDING F ILAMENT T HEORY A muscle contracts when the thin filaments in the muscle fiber slide over the think filaments. This process is known as the Sliding Filament Theory 1. Myosin attaches to Actin (crossbridge) 2. Powered by ATP, the myosin crossbridge changes shape and pulls the actin filament toward the center of the sarcomere 3. The cross-bridge is broken, myosin binds to another site of actin and the cycle begins again Muscle Contraction Video

9. C ONTROL OF M USCLE C ONTRACTION Motor neurons connect the central nervous system to skeletal muscle cells Impulses from motor neurons control the contraction of skeletal muscle fibers

10. H OW M USCLES AND B ONES I NTERACT Skeletal muscles are joined to bones by tough connective tissue called tendons Tendons pull on bones Most muscles work in opposing pairs, meaning when one muscle contracts the other muscle relaxes

11. M USCLE S TATIONS Station 1: Muscle Histology Look in the microslide viewers and draw the three different types of tissues. Make sure to LABEL and COLOR Station 2: Muscle Diseases Only need 3 Station 3: Muscle Contraction and Size Use the string to measure If you finish, work on the Muscle Stations Analysis and Review Questions!