Transcript The Muscular System

The Muscular System
1. The main function of
the muscular system is
to work with our
skeletal system to help
us move.
How Many?
2. There are
about 600
muscles in your
body.
Involuntary
3. Muscles that are NOT
under your conscious
control are called
involuntary muscles.
• Involuntary muscles
are responsible for
activities such as
breathing and
digesting food.
Voluntary
5. The muscles that are
under your control
ARE voluntary
muscles.
• Smiling and turning
the pages in a book are
actions of voluntary
muscles.
6. Three Types of Muscles
• Skeletal muscles (striated)
• Smooth
• Cardiac
6. Skeletal Muscles
• Voluntary
• Attach to bones by
tendons
• Work in pairs
– As one muscle relaxes, the
other contracts
• Cells are long and thin
• Cells have striped
appearance (striated)
• React quickly, but tire
quickly
7. Smooth Muscles
•
•
•
•
•
Involuntary
Muscles of internal organs (stomach and intestine)
Cells are smaller and shorter
Cells are arranged in compact layers
React slowly, but do not tire.
8. Cardiac Muscles
• Found only in the heart
• Has characteristics of both
skeletal and smooth
muscles
• Cells are striped and
arranged in bundles
(skeletal)
• Cells are shorter and
involuntary
• Never tire
9. How do muscles work?
• Muscles work by contracting, or becoming
shorter and thicker.
• Because muscle cells can only contract, not
extend, skeletal muscles must work in pairs.
• While one muscle contracts, the other
muscle in the pair returns to its original
length.
Muscles in Action
• To bend the elbow, the biceps muscle on the front
of the upper arm contracts, while the triceps
muscle on the back of the upper arm returns to its
original length.
Muscle Health
• Exercise is important for maintaining
muscular strength and flexibility.
• Exercise makes individual muscle cells
grow wider, thicker and stronger.