Bell Ringer
Muscle Facts: You can write your answer on your muscle packet.
 How many skeletal muscles do we have in our body?
 How many muscles does it take to smile? To frown?
 How many muscles does the tongue have?
 How do we create muscle memory?
 What is the strongest muscle in relation to the job it does?
 What percentage of our total body weight do muscles make up?
Unit 2:
Muscular System
WHAT DOES THE MUSCULAR SYSTEM DO?
Objectives
Content Objective: The students will be able to compare and contrast the three
types of muscle; smooth, cardiac and skeletal by creating and comparing posters
in order to determine the factors that differentiate them on their notes.
Language Objective: The students will be able to determine key information
while reading a short paragraph describing various types of muscle in order to
create a poster that teaches the class one of the three muscle fibers.
Purpose of the Muscular System
 Muscle attaches to __bone__ in order to move our
skeletal system
Muscle help you to move. Muscles cannot push but they
can pull on your bones in order for you to make
movements such as talking, walking, smiling, etc.
Two Types of Muscles
VOLUNTARY
oMuscles you can control
o Most of them work to move your bones
o The brain sends a message to your muscles to
relax or contract depending on the movement
you want to do
INVOLUNTARY
oMuscles you can not control
o The brain does not need to send these muscles a
message
o They know their job and they automatically do
it
o Examples:
o Muscles in your heart
o Muscles in your digestive system
o Tiny muscles on the bottom of your hairs that makes your
hair stand up when you are cold/scared
Three Types of Muscles
In your group….
Read the three handouts
Create a chart that includes the following
information for all three types of muscles :
 Muscle Type Name
 Identify if it is a voluntary or involuntary muscle
 How they contract
 Where they are located
 Draw a picture of what it looks like
Are Cardiac, Smooth and Skeletal
Muscles Voluntary or Involuntary?
SKELETAL MUSCLE
Voluntary
We think about the
movement that we want
to do and our brain sends
that message to the
muscles to contract which
pulls on our bones to
make them move.
SMOOTH MUSCLE
Involuntary
We do not think about
digesting food, expanding
or relaxing our bladder, or
breathing
CARDIAC MUSCLE
Involuntary
We do not think about
making sure our heart
pumps 100,000 times a
day
How do Smooth, Cardiac and Skeletal
Muscles Contract?
SKELETAL MUSCLE
Muscles attach to bones
via tendons so that when
the muscle contracts it
causes the bone to move
at the joint
Skeletal muscle is striated
and has a circular
arrangement
SMOOTH MUSCLE
Smooth muscles can
contract in all directions
because the muscle fibers
lay in different directions
CARDIAC MUSCLE
Similar to skeletal
muscles in that the muscle
is striated. Pacemaker cells
and the nervous system
cause this muscle to
contract.
What do Smooth, Cardiac and Skeletal
Muscles Look Like?
SKELETAL MUSCLE
SMOOTH MUSCLE
CARDIAC MUSCLE
Where Are Smooth, Cardiac and Skeletal
Muscles Found?
SKELETAL MUSCLE
SMOOTH MUSCLE
Tendons attach skeletal
muscle to bone
Found in hollow parts of
your body
Any muscle that attaches
to bone is a skeletal
muscle
Examples: Stomach,
intestines, blood vessels,
bladder, female/male
reproductive system,
respiratory tract, iris of the
eye
Examples: Biceps,
Triceps, Pectoralis,
Latissimus Dorsi,
Abdominals
CARDIAC MUSCLE
ONLY located in the heart
Skeletal Muscle
These muscles are VOLUNTARY ~ you control these muscles.
These muscles are connected to your bones
◦ Provide movements such as RUNNING, EYE MOVEMENTS, FACIAL EXPRESSIONS,
etc. possible.
There are 650 individual SKELETAL muscles and make up 40% of your body
weight.
Smooth Muscle
Smooth muscles are involuntary
They are located around the hollow parts of your body.
 Example: stomach, intestines, blood vessels, bladder, etc.
These muscles help in respiration & digestion. (functions that happen automatically)
These muscles can contract in all directions because the muscle fibers lay in different
directions.
Cardiac Muscle
Cardiac muscle is involuntary
The cardiac muscle is found in your HEART and never fatigues!
It contracts automatically & squeezes the walls of the heart inward.
The heart beats about 100,000 times per day.
Functions of Muscles
What were the functions identified for the skeletal system?
Do you think any of those functions are the same for our muscular
system?
Talk with the person sitting next to you about what functions you
think the muscular system serves.
 What did you and your partner identify?
Functions of Muscles
1. Posture
a) In your opinion how do muscles provide posture?
b) What is posture?
c) What muscles are primarily responsible for holding our posture?
Definition: The position of the limbs or the carriage of the body
How Do Muscles Provide Posture?
◦ Muscles contract to hold the body still or in a particular position
◦ The muscles responsible for posture have the greatest endurance of all skeletal muscles
◦ They are responsible for holding up the body throughout the day without tiring
◦ The core (abs, pelvis, and lower back, hip flexors) are primarily responsible for providing posture
Functions of Muscles Cont.
2. Movement:
 In your opinion, thinking about what we talked about with the skeletal system, how do
muscles provide movement?
 Which type of muscles allow for movement?
How do muscles provide movement?
◦ Muscles are the only tissue in the body that are capable of contracting and therefore move
other parts of the body
◦ Muscles connect to bones by ligaments
◦ Muscle fibers convert chemical energy into movement
◦ Which type of muscles allow for movement?
◦ Skeletal Muscles
◦ Example: Biceps
Functions of Muscles Cont.
3. Stabilize Joints
 What does the word stabilize mean?
 What do we already know about joints?
 In your opinion, how do muscles stabilize joints?
Definition: To make or hold stable, firm
How do muscles stabilize at the joints?
 Muscles limit movement at the joint and/or provide balance at the joint to
make it more stable
 Muscle tone is essential for providing stability at the joint
 Example: Weak muscles around your shoulder or knee allow them to dislocate more easily
Functions of Muscles Cont.
4. Vital Functions
 What does the word vital mean?
 In your opinion, what are vital functions that muscles provide?
 Think of the three types of muscles discussed
Definition: Necessary to Life
What are vital functions that muscles provide?
 Cardiac muscles involuntarily contract to allow our heart to pump blood
 Cardiac muscle contracts to pump blood to the rest of our body and relaxes to fill the heart up with blood
 When air is drawn into the lungs, the muscles of the diaphragm contract which allows air to inflate the
lungs
 When the diaphragm contracts involuntarily and air is inhaled at the same time, the space at the back of the vocal chords in the
throat closes and causes hiccups
 Moves food through the digestive system