Transcript The Skeletal System

The Skeletal System
What our bones do and are made of
Functions of the Skeletal System
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Protect our soft internal organs
Provide the body with support and structure
Stores important minerals that the body needs
Works with the muscular system to allow movement
Make most of the blood cells for our circulatory system
Protection
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There are 206 bones in the human bodies (at least for most
of us.
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Skull (29 bones) – protects the brain and sensory organs (eyes,
ears, tongue, nose)
Spinal Column (26 bones) – protects the spinal cord
Rib Cage (25 bones) – protects the heart and lungs, and allows us
to breath by supporting the diaphragm
Shoulders, Arms, and Hands (64 bones) – allow movement for
survival
Pelvis, Legs, and Feet (62 bones) – allow movement for survival, so
we can escape predators and find food
Bones
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There are four layers to your bones:
Pariosteum – the outer layer that is thin and dense. It contains the
blood vessels and nerves.
 Compact Bone – the next layer that is very smooth and hard. It is
made up of round bone cells that have blood vessels running
through the center of them.
 Cancellous – the next layer down looks spongy, but is still very
strong. It protects the bone marrow.
 Bone Marrow – the inner most layer
that is like a very thick jelly and makes
the blood cells
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Mineral Storage
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Bones are made up of . . .
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30% living tissue
45% mineral deposits
25% water
Bones store calcium and phosphorus. As the blood needs
more of these minerals they are released from the bones,
but the bones need them as well to stay hard and strong.
Bone Marrow
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There are two types of marrow:
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Red – this is the site for blood cell production. It makes red
blood cells, white blood cells, and platelets.
Yellow – contains fatty connective tissues that can be broken
down and used as energy during starvation
Cartilage
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Cartilage is the elastic, fibrous tissue that is flexible.
It can be found in joints to cushion and allow smooth
movements
Some types of cartilage are used to allow flexibility, like in
your ears, nose, and trachea.
Some cartilage is meant to bear weight and squish, so the
bones do not crack.
Cartilage has no blood vessels running through it, but is
still living tissue.
As a fetus most of your skeleton is made of cartilage.
Breaking Bones
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There are several different types of
breaks or fractures depending on their
severity.
The pain is different for everyone, but
usually it is a deep ache and you may feel
nausea
The best thing is to not move the area
that your think might be broken.
Immobilize the area and get to a doctor.
Your osteocytes will start producing
more bone cells and eventually your
break will heal
Fun Facts
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Bones fuse with age, so when you were a baby you had
about 300 bones
Bones in the hand and feet vary, so not every one has
exactly the same number of bone. It usually ranges
between 206 and 216 bones
Half the bones in your body are in your hands and feet
Your femur (thigh bone) is stronger than steel rod of the
same size and shape
Standing and sitting squeezes the cartilage between the
discs in your spine, so you are about ½ inch shorter at
the end of the day
Human
Skeleton