1. Chapter 1, Section 2, Pages 14 - 19
The Muscular System
Chapter 1, Section 2, Pages

2. What are Muscles?
Muscles are organs that relax, contract, and provide force to move your body parts.

3. 3 Types of Muscle Tissues

4. Classification of Muscle Tissue
Skeletal Muscles
Voluntary Muscles that move the bones
Most common muscle type
Attaches to bones by thick bands of tissue called tendons
They are striated (appear striped)
Tire more easily than involuntary muscles

5. Muscle Tissue Continued…
Cardiac Muscle
Found only in the heart
It is striated
Contracts about 70 times per minute every day of your life
It’s an involuntary muscle.

6. Muscle Tissue continued…
Smooth Muscles
Located in your intestines, bladder, blood vessels and other internal organs
Nonstriated
Involuntary muscles that slowly contract and relax

7. Working Muscles Pairs of skeletal muscles work together
One muscle contracts, the other relaxes
Muscles always pull (never push)
For example, when you bend your arm, your bicep muscle contracts (tightens) while your triceps muscle relaxes (returns to its original length)

8. Changes in Muscle
Muscles can become larger or smaller, depending whether or not they are used.
Muscles that are exercised become stronger, and sometimes, larger.
Muscles that are not used, become smaller, soft, flabby and will lack strength.
Athlete vs. nonathlete

9. How muscles Move Muscles need chemical energy to contract and relax
Blood carries energy-rich molecules to muscle cells
Chemical energy is stored and released
Muscle contractions = release of energy changes to mechanical energy (movement) and thermal energy (heat)
When the supply of energy-rich molecules in a muscle is used up, the muscle becomes tired and needs to rest. During resting period, blood supplies more energy-rich molecules to muscle cells. The heat produced by muscle contractions helps keep your body temperature constant.

10. Major Muscles Muscle Location Hamstring Back of Thigh
Abdominals Stomach
Bicep Front of upper arm
Deltoid Shoulder
Quadriceps Front of Thigh
Trapezius Upper back
Muscle Location
Calf Muscle Back of lower leg
Pectorals Chest
Obliques Sides of stomach
Gluteus Maximus Butt
Triceps Back of upper arm