1. Human Systems:
Muscular System

2. Muscle Muscle cells have contractile proteins Contract and relax
Help in movement
Heart muscles
Blood vessels
Stomach

3. Types of muscles 3 types of muscles
Smooth muscles (digestive tract, blood vessels)
Cardiac muscle ( heart)
Skeletal muscle (attached to bones)
Muscle action could be voluntary or involuntary
Smooth and cardiac muscles are involuntary
Skeletal muscles could be voluntary or involuntary (e.g. blinking of eyes)

4. Types of muscles

5. Movement Muscles are attached to bones through tendons
When muscle shortens (contracts), the bones are pulled closer
When muscle relaxes, bones move away
Musculoskeletal system - movement

6. Movement Muscles work in pairs
Flexor (Biceps) - bends a part of the body
Extensor (Triceps) – straightens a part of the body
Bicep is flexor
Tricep is extensor

7. Levers in human body Lever
Levers increase the amount of work done by a force (mechanical advantage)
Three types of levers

8. Levers in human body

9. Muscle and exercise Resistance exercise (increases muscle strength)
Aerobic exercise (strengthens heart)

10. Muscle injury and problems
Strain – muscle or tendon over stretched or torn
Tendinitis – inflammation of tendons
Anabolic steroids – can be helpful in increasing muscle strength but may be associated with causing other problems
Muscle fatigue and lactic acid