1. Muscle System

2. Muscle Tissue – 3 types

3. Skeletal Muscle: Origin and Insertion
Origin – attachment to more stationary bone
Insertion – attachment to more moveable bone

4. Tendon – holds muscle to bone
Made of dense fibrous connective tissue

5. Bursae – small fluid filled sacs, lies between tendons and some bones, covered by synovial membrane

6. Myosin and Actin – Myofilaments of Muscle fibers

7. Sarcomere – basic functional (contractile) unit of skeletal muscle

8. Sliding Filament Model

9. Functions of the muscular system
Movement
Posture –
Tonic contractions – hold muscles in place, maintains posture
Heat production - ATP

10. Fatigue Overstimulation of muscles without adequate rest
Oxygen debt – when oxygen levels go low, then switching to lactic acid fermentation, which does not require oxygen.

11. Motor Unit

12. Threshold Stimulus
Minimal level of stimulation required to cause a fiber to contract
All or none – Each fiber contracts completely or none at all.
A muscle is made up of different muscle cells that are controlled by different muscle units that can contract independently of each other.

13. Muscle contractions Twitch - quick jerky response to a stimulus
Tetanic – more sustained and steady response, like holding a box
Isotonic – movement at a joint, same tension
Isometric – same length of muscle, change in tension

14. Strength training versus endurance training
Contracting muscles against heavy resistance
working out, isometric training
Number of myofilaments increase (actin and myosin), muscle fiber numbers stay the same, just get bigger.
Aerobic training – no hypertrophy
Increases a muscles ability to sustain exercise over time
Running, biking
Increase number of blood vessels and mitochondria in a muscle without increasing size