2. Unit 5 MUSCULAR SYSTEM

3. 2. the 3 Types of MUSCLE TISSUE SMOOTH- in walls of organs, 1 nucleus, involuntary, slowest CARDIAC- heart, rythmical, involuntary, 1 nucleus, least fatigue, striated SKELETAL- attach to skeleton, voluntary, many nucleus, striated

4. The 5 functions of MUSCLES Stabilize joints Allow us to hold positions Movement Produce heat Keep blood moving

5. 1.Structure of Muscle Tendons attach muscle to bone Muscles are covered with FASCIA A bundle of muscle fibers are wrapped in a Fascicle One muscle FIBER is made up of many actin and myosin Actin and Myosin are the contractile unit. They slide from Z line to Zline( a SARCOMERE)

6. How does a Muscle Contract? A nerve stimulates the muscle Calcium and ATP are released This stimulates actin filaments to slide past myosin filaments All or none Law- when a muscle is stimulated it contracts completely or not at all

7. 3. Muscle Tone Strength of contraction depends on the # of muscle fibers stimulated Origin- stationary bone Insertion- moving bone Muscle Tone- some fibers are always contracted

8. 4. Isotonic & Isometric Contractions Muscle short & thickMuscle length not change, just tension Muscle Tone

9. Locate the following Muscles Deltoid- shoulder Pectoralis- chest Biceps- anterior upper arm Quadreceps- front and side of thigh

10. Muscles continued Triceps- posterior upper arm Gluteus- buttock and back of thigh, largest muscle of body Hamstring- behind knee

11. 5 Muscles of Facial Expression Frontalis- forehead Obicularis oris- lip, pucker Obicularis oculi- eye Buccinator- cheek Zygomatic- cheek to corner of lip, smile

12. 4 Muscles of MASTICATION (chewing)

13. The End