1. The Muscular System
Chapter 21-3

2. Science Words
• Muscle
• Voluntary muscle
• Involuntary muscle
• Skeletal muscle
• Tendon
• Smooth muscle
• Cardiac muscle

3. Moving the human body
• Muscle-an organ that contracts
and gets shorter- this provides
the force to move your body
parts.
Muscles of the
body

4. Muscle Control
• Voluntary muscles- muscles
that you are able to control
• Examples are leg and arm
muscles
• Involuntary Muscles- you can
not move them consciously.
They just keep working
• Examples- heart

6. Types of Muscles-skeletal
• Skeletal Muscles-muscles that
move bones
• Attached to bones by tendons
• Most numerous in the body
• Look striped or striated
• Voluntary muscles

7. Types of Muscles-Smooth Muscles
• Smooth muscles- nonstriated
• Involuntary
• Move the internal organs
• Contract and relax slowly
• Example- small intestine

8. Types of Muscles-Cardiac Muscle
• Cardiac muscle-found only in
the heart
• Involuntary
• Striations
• Contracts about 70 times a
minute every day of your life.

9. Types of Muscles
Types of muscles

10. How Muscles Work
• Skeletal muscles-when one
muscles contracts- another
muscle relaxes
• Muscles always pull- never
pushes
• Muscles use glucose
• Produce thermal energy when
they contract
• Muscles that are not exercised
become smaller
How muscles work

11. Muscles and bones work together
Working together
A review