Download The Musculoskeletal System

THE MUSCULOSKELETAL
SYSTEM
Unit 7 – Mr. Mundy
Do Now – March 9th
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Write down HW assignment in your
Agenda
Take out a sheet of lined paper and
a pen/pencil
Exam will begin shortly
What is the Musculoskeletal System?
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The hard structures within our
bodies are part of the skeletal
system.
The Skeletal System provides
support, protection, and
movement for our bodies.
Press down on your wrist and
you will feel bones and muscles.
What is the Musculoskeletal System?
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A bone is a hard tissue made
mostly of cells, collagen, and
calcium.
Collagen is a protein that
forms strong fibers in the bone.
Calcium is a mineral that adds
strength to the collagen fibers.
What is the Musculoskeletal system?
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The human body has over
200 bones that make up
the skeleton.
Diets rich in calcium and
Vitamin D help to maintain
strong teeth and bones.
Functions of the Skeletal System
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Bones in the skeletal are not all
smooth, have different sizes,
rough spots, pits, and holes where
blood vessels and nerves enter
and leave.
The bones in our bodies have
blood vessels and nerves to
deliver nutrients and signals.
This is why breaking a bone is SO
PAINFUL!
Functions of the Skeletal System
Functions
Examples
1. Protection
-Rib cage protects our vital organs: heart, lungs,
liver
-Skull protects your brain
2. Support
Without our bones and muscles, our bodies
would not have support.
3. Attachment points
Bones in our legs, arms, neck, and chest give our
bones places to attach.
4. Storage
Skeletal system helps to store calcium &
phosphorus.
Stop & Check
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Write 2 things that you have just learned in this
lesson so far.
1._______________________________________
_________________________________________
_________________________________________
2._______________________________________
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Bones Connect At Joints
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Because bones are hard, they
cannot bend.
However, our bodies can bend,
twist, and spin.
Soft tissue called joints, holds
two bones together.
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Ligaments connect bones.
They are similar to a strong
rubber-band because they
stretch when we move.
Cartilage is a strong, yet
flexible tissue that reduces
friction and increases
flexibility in our bones.
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Try twisting your LOWER
ARM without moving
your upper arm!
Can you do the same
with your leg?
The structure of the joint
determines its movement.
Types of Joints
Description of Joint
1. Hinge Joints
Allow bones to move back & forth
Examples: fingers, elbows, and knees
2. Saddle Joints
Allow bones to move back and forth and
side to side, but have limited rotational
ability.
Example: Thumbs
3. Ball-and-Socket Joints
Allow bones to move and rotate in nearly all
directions.
Example: hips and shoulders
Description of Joint
4. Pivot Joint
Allows bones to rotate
Example: Neck
5. Gliding Joint
Allows bones to move side to side or front
to back
Examples: ankles and wrists
6. Immovable Joint
Allows very little or no movement
Examples: Skull
The Muscular System
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Muscles are parts of the body
that help our bodies move.
Muscle: is a tissue made of
long cells that contract
There are more than 620
muscles in the human body.
The Muscular System
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Muscles are made of
bundles of muscle cells
called muscle fibers.
Muscle fibers contain
hundreds of nuclei and
mitochondria
Muscle fibers are arranged
length-wise and usually
overlap other muscle fibers.
The Muscular System
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Since Muscle fibers overlap
each other, during muscle
contractions the filaments move
closer to each other.
When muscle fibers contract,
the fibers become shorter.
Contraction is a shortening of
muscle fibers in the body.
Muscle Contractions
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What do you think makes your muscles contract?
<write your response below>
Muscle Contractions
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Muscle cells have nerve cells
that start a chemical reaction
in the muscle cell.
This chemical reaction causes
muscle fibers to shorten and
the muscle will contract.
Muscles require lots of energy
and oxygen to contract.
Review…
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Recall that cells form tissues,
tissues form organs, organs
form organ systems, and
organ systems form an
organism.
Muscles work the same way!
Muscle cells form tissue. There
are 3 different types of
muscle tissue in our bodies
Types of Muscle
Type of Muscle
Function
1. Skeletal Muscle
Help cause movement of your body
2. Cardiac Muscle
Found only in the heart
3. Smooth Muscle
Found only in the organs of the body, such
as your stomach and blood vessels.
Interactions of the Musculo-skeletal
System
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Our bones alone cannot
move our bodies.
Similarly, muscle contraction
is only part of movement
In order for us to move, the
muscular system must work
with the skeletal system.
Our skeleton provides
support for our muscles
How Do You Move?
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Usually, a muscle is connected
to at least 2 different bones.
Tendons: connect bones to
muscles
Cartilage and ligaments are 2
other types of connective
tissue.
Opposing Muscle Groups
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The bicep muscle causes your arm to bend.
Flexion is the bending of a limb that decreases the
angle between the bones of a limb.
Just think… when someone asks you “flex” your
arms, you make your arm bend!
Review…
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What type of muscle do we use in our arm?
(voluntary? Involuntary? Cardiac?)
Also, are the muscles in our arm shortening? Or
becoming longer when we flex our biceps?
Opposing Muscle Groups
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Muscle can contract and
become shorter, but they
CANNOT actively lengthen.
Extension is the straightening of
a limb.
 When
you straighten your limb,
the angle of between the bone
increases.
Opposing Muscle Groups
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Arrangement of muscles is
often in opposing groups
This means that as one
muscle flexes, the other is
relaxing.
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Example: Your Bicep/Tricep
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