ACTIONS OF OUR MUSCLES
Unit 2 – Muscular System
OBJECTIVES
• Content Objective: The students will be able to differentiate between the
movements of flexion, extension, adduction and abduction while evaluating
motion pictures on a worksheet.
• Language Objective: Students will be able to create a definition for the
prefix ‘ab’ and ‘ad’ using a variety of words they know which begin with the
prefixes in order to define and understand the movements of abduction and
adduction within their notes.
REVIEW OF MUSCLE TYPES
• Think to yourself or write down…
• Muscles are only able to make what movement?
• What is the difference between voluntary and involuntary muscles?
• Where are smooth muscles located in your body? How are the
fibers arranged?
• Where are cardiac muscles located in your body? How are the
fibers arranged?
• Where are skeletal muscles located in your body? How are the
fibers arranged?
FUNCTIONS OF MUSCLES
 What were the functions identified for the skeletal 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. Giving Shape to the Body
***A.K.A. 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 tendons
• Muscle fibers convert chemical energy into movement
• Which type of muscles allow for movement?
• Skeletal Muscles
• Example: Biceps
FUNCTIONS OF MUSCLES CONT.
• 3. Support of the Skeletal System
***A.K.A. 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
HOW MUSCLES MOVE OUR
SKELETAL SYSTEM
• Which type of muscle moves our skeletal system?
• How do they move our skeletal system?
• What specific type of movements do our muscles allow us to do with our
skeletal system?
• HINT: Think about the movements that our joints allow for
MUSCLE ACTIONS
Flexion
Extension
• What do you think the definition of
flexion is?
• What do you think the definition of
extension is?
• Dictionary Definition – The act of
bending a limb
• Dictionary definition – The act of
extending (stretching out)
• In relation to the body – Movement
that DECREASES the angle between
two body parts (bones)
• In relation to the body – Movement
that INCREASES the angle between
two body parts (bones)
PREFIX ‘AB’
• On a piece of paper…
• Write as many words that you can think of that have the prefix ‘ab’ in one
minute
• Example: Abduction
• Come up with a definition for each word you wrote down – You have 1-2
minutes to do this
• Find another person in the room and add any words they have on their list
that you do not have to your list.
• Given the words that you cam up with and their definition, find a
commonality in these definitions that the prefix ‘ab’ means
MUSCLE ACTIONS CONT.
Abduction
• What does the word abduction
mean?
• ‘Ab’ is a prefix – what other words
do you know with the prefix ‘ab?’
• Latin origin for “ab” means away
from.
• In relation to the body - A
movement AWAY FROM the midline
• What is the midline of the body?
Adduction
• What does the word adduction
mean
• ‘Ad’ is a prefix – what other words
do you know with the prefix ‘ad?’
• Latin origin for ‘ad’ means toward
• In relation to the body – A
movement TOWARDS the midline
MUSCLE ACTION AND JOINT
ACTIVITY
• In Pairs…
• Look at the picture and identify the following information…
•
•
•
•
Type of muscle action occurring
Common name of the joint that the movement is occurring at
The type of joint that the movement is occurring at
The medical name for the bones that create that joint.
• Example:
#
1.
Picture
Muscle Action
Common
Joint Name
Type of
Joint
Medical
Name for
Bones at Joint
Thumb
Abduction
Thumb Joint
Saddle
Joint
Metacarpal
and
Phalange
TENDONS AND LIGAMENTS
TENDONS AND LIGAMENTS
Tendons
• A fibrous connective tissue that
attaches muscle to bone.
• Tough yet flexible
• Tendons purpose is to move the
bone
Ligaments
• A fibrous connective tissue that
attaches bone to bone
• Serves to hold structures together
and keep them stable – particularly
at the joint
• Slightly elastic so they can be
stretched and gradually lengthen,
increasing flexibility
• Double jointed refers to people who
have highly elastic ligaments
WHAT TENDONS HAVE YOU HEARD
OF?