1. BY Ricardo Castrejon Max Calderon Lizette Chapa
Muscular System
BY Ricardo Castrejon
Max Calderon
Lizette Chapa

2. Introduction
The Muscular System is a system of 600+ muscles that produces movement, protects internal organs, produces body heat, and maintains posture.

3. Kinds of Muscle
Cardiac Muscle- forms the walls of the heart and contracts to circulate blood.
Visceral or Smooth Muscle- found in the internal organs, contract to cause movement. Ex. Digestive and Respiratory organs, blood vessels, and eyes.
Skeletal Muscle- attached to bones and causes body movement.

4. Voluntary vs. Involuntary
Voluntary Muscles- muscles a person has control over. Ex. Skeletal Muscles
Involuntary Muscles- Muscles that function without conscious thought or control. Ex. Cardiac and Smooth Muscle.

5. Muscle Functions Produces Movement Protects Internal Organs
Produces Body Heat and Energy
Maintains Posture

6. Muscle Attachment Skeletal Muscle attach to bones in different ways.
Tendons- strong, tough connective-tissue cords.
EX. Calf muscle to the heel by Achilles tendon.
Fascia- tough, sheet like, membrane that covers and protects the tissue.
EX. Muscles in trunk and back surrounded by lumbodorsal fascia.

7. Muscle Attachment
When a muscle attaches to a bone, the end that does NOT move is the origin.
When a muscle attaches the end that moves when the muscle contracts is the insertion.

8. Muscle Movements Adduction- moving toward the midline.
Abduction- away from the midline.
Flexion- bending a body part.
Extension- straightening a body part.
Rotation- turning a body part around its axis.
Circumduction- moving in a circle at a joint.

9. Muscular Diseases
Muscular dystrophy- group of inherited diseases that lead to chronic, progressive muscle atrophy. Usually appears early in childhood; most types result in total disability and early death.
Myasthenia gravis- chronic condition, where nerve impulses are not properly transmitted to the muscles. Leads to the progressive weakness and paralysis.

10. Muscular Diseases
Muscle spasms- sudden painful, involuntary muscle contractions. May result from overexertion, low electrolyte levels, or poor circulation.