1. Muscular System 11 th Grade Health

2. Purpose Provides bodily movements Moves blood, air, food and waste through our body

3. Structures and Functions Voluntary Muscles – muscles that are under your control (skeletal muscles) Involuntary Muscles – muscles that function automatically (heart, etc)

4. Types of Muscles Skeletal – muscles attached to bones in the skeletal system; voluntary Cardiac – the heart muscle; involuntary Smooth – involuntary muscles that help with movements of internal organs, such as digestive (peristalsis) and circulatory (lining of blood vessels).

5. Major Muscles in Body Quadriceps – front thigh Hamstrings – back thigh Gastrocnemius – calf Gluteals – buttocks Pectoralis – chest Latissimus dorsi – back Trapezius – upper back/neck Deltoids – shoulders Biceps – front upper arm Triceps – back upper arm

6. Muscle Movements FLEXION Decreases angle between bones EXTENSION Increases angle between bones HYPEREXTENSION Greater than 180 degrees

7. ABDUCTION Move away from the midline ADDUCTION Move toward the midline

8. ROTATION Movement of bone around a longitudinal axis CIRCUMDUCTION Proximal end stationary while distal end moves in a circle

9. PRONATION Moving hand from anterior to posterior position (radius over ulna) SUPINATION Moving hand from posterior to anterior (radius to ulna parallel)

10. INVERSION Sole of foot turned medially EVERSION Sole of foot turned laterally

11. DORSIFLEXION Instep of foot moved up toward shin (standing on heels) PLANTAR FLEX Toes pointed downwards

12. Types of Muscle Contractions Muscle Contractions can be divided into: Isotonic (meaning same tension) Isometric (meaning same distance or not moving) Isokinetic (meaning same speed)

13. Isotonic Contractions Concentric Contraction contraction in which the muscle decreases in length (shortens) against an opposing load Example: pulling up portion of bicep curl

14. Eccentric Contraction contraction in which the muscle increases in length (lengthens) as it resists a load Example: downward portion of the bicep curl, when the arm returns to its starting position

15. Isometric Contraction Contraction in which no movement takes place, because the load on the muscle exceeds the tension generated by the contracting muscle. Example: carrying an object in front of you as the weight of the object is pulling your arms down but your muscles are contracting to hold the object at the same level.

16. Isokinetic Contraction The muscle contracts and shortens at the same speed throughout the entire range of motion. A special piece of equipment known as an Isokinetic Dynamometer is usually required.