Download The Muscular System

Let’s just say the heroes of the 1980’s action movies used their muscular
system more than kind words to solve their problems.
The Muscular System
The Human Body Lesson
What is the Muscular System?
 The muscular system is
what moves the body
 You have about 650
muscles in your body.
 Muscles make up about
40% of your total body
weight.
 There are two main types of
muscles.
Ummm I don’t think your circulatory
system should be showing like that.
The Two Main Types of Muscle
 Skeletal Muscle (Striated) is
muscle that is attached to
our bones and move them.
 Our biceps and triceps are
skeletal muscles.
 Smooth Muscles are found in
the blood vessels, the skin,
and organs such as the
esophagus, stomach, and
intestines.
 These muscles push food
and blood through our body
but do not move the
skeleton.
 There is a third kind of
muscle found only in the
heart which is called Cardiac
Muscle.
Gymnasts must have complete control
of their skeletal muscles.
Voluntary and Involuntary Muscles
 Muscles that you have
control over are called
Voluntary Muscles.
 These are found in your
arms, legs, fingers, toes…all
over your body!
 Involuntary Muscles are out
of your control.
 These are your smooth
muscles and cardiac muscle.
 There are a few muscles that
are normally involuntary but
can be controlled at times.
(diaphragm, eyelids, tongue.)
That look says, “Go ahead
and try to take my lunch
money.”
How Do Muscles Work?
 Muscles can only pull, they
cannot push!
 Many skeletal muscles
work in pairs to move
bones.
 The bicep on your upper
arm works with the tricep
underneath it to bend the
elbow.
 When muscles pull or
contract too long, or too
strong, you can get a
cramp.
 When muscles relax they
expand.
How do Muscles Work?
 Skeletal muscles are
attached to the bones with
thick rubberband-like cords
called tendons.
 Muscles need energy in
order to work.
 Special enzymes in the
muscles break down food to
get energy.
 As the muscle works, it
produces waste called lactic
acid.
 If too much lactic acid builds
up, the muscle loses some
ability to contract.
The Achilles
Tendon is the
largest tendon
in the human
body.