Muscles
Interesting Muscle Facts
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Thirty facial muscles create looks like surprise, happiness,
sadness, and frowning
Eye muscles are the busiest muscles in the body. Scientists
estimate they may move more than 100,000 times a day
Largest muscle in the body is the gluteus maximus muscle
in the buttocks.
It takes 10 muscles to smile, 12 muscles to frown.
Smallest muscle in our body is in the inner ear and is called
stapes
What makes our bodies move?
MUSCLES!!!
◦ Marionettes are puppets on
strings. By pulling different
strings, you make these puppets
dance, bow or wave their arms.
Your skeleton is similar to the
puppet’s body. It does not move
unless something pulls on its
bones. The strings that pull on
your bones are your MUSCLES.
What is Muscle?
Muscle is a tissue composed of
bundles of elongated cells
capable of contraction and
relaxation to produce
movement in an organ or body
part.
Parts of the muscle
Tendon:
• white cord made up of
extremely strong tissues
• Connects muscle to the
bone
Body:
• thick part of the muscle
Aponeurosis:
• membrane of connective
tissue separating the
muscle from the adjacent
muscles
Tendon vs. Ligament
Functions of Muscles
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B.
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D.
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Movement of limbs and organs
Posture maintenance
Even while you are still your muscles are continuously at
work in order to maintain your posture
Joint stabilization
Without muscles, some of our joints would not stay in place
Heat Release
Muscle contraction requires chemical energy
75% of this chemical energy is transformed into thermal
energy (ie. heat).
The thermal energy that is released helps maintain body
temperature at 37°C
Voluntary vs. Involuntary Muscle
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Muscle can be voluntary or involuntary
a) Voluntary - consciously controlled by the brain
Ex: raising your arm to scratch your head
b) Involuntary - not consciously controlled by the brain.
Ex: the contraction of the diaphragm during inhalation
There are 3 Types of Muscle
All the functions of muscle are carried out by 3
different muscle tissues:
1.
Skeletal (Striated)
2.
Smooth
3.
Cardiac
Skeletal Muscle (voluntary -striated)
Skeletal Muscle
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The only muscles that perform voluntary movements.
Striated appearance
Attached to the bones of the skeleton
Can generate a lot of force but tire easily: low
endurance
Smooth Muscle (Involuntary - no striations)
Smooth Muscle
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Involuntary
No striations
Make up the walls of the internal organs such as the
bladder, stomach, and uterus.
Do not generate as much force as skeletal muscle but
do not tire easily: medium endurance
Cardiac Muscle (involuntary, no
striations)
Cardiac Muscle
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Involuntary
No striations
Found only in the heart
Has great strength and endurance
Antagonistic Muscles
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All muscles work in pairs. Whether they are striated
muscle, smooth muscle or cardiac muscle makes no
difference, all muscles must work in pairs.
Antagonistic Muscle
Pair
When biceps contracts, the
triceps elongates and
relaxes.
When the triceps contracts
the biceps elongates and
relaxes.
biceps
triceps
Review Questions
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What is a muscle?
Describe the 3 parts of a muscle.
What is the difference between a tendon and a
ligament?
What are the 4 functions of muscles?
What are the 3 different types of muscles and where
can they be found in the body?
Give an example of an antagonistic muscle pair.
What happens to the shape of a muscle when it
contracts? And when it relaxes?