“BONING UP”
ON THE
SKELETAL SYSTEM

A newborn baby has more bones than an adult. A baby is born with
300 bones. An adult only has 206.
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Your hand has 27 bones .

Your face has 14 bones.

Smallest and The Longest:
 The longest bone in your body is your thigh bone, the femur it is about 1/4 of your height.
 The smallest bone in your body is the stirrup bone in your ear which can measure only 1/10 of an inch.

Humans and giraffes have the same number of bones in their necks? A Giraffe’s neck vertebrae are just much, much longer!

Your Femur (thigh bone) is stronger than concrete.
 Bone is stronger, inch for inch than the steel used in skyscrapers.

Babies are born without the patella (knee bone) it develops between ages 2 and 5.

One fourth of your bones are located in your feet.

The jawbone is the hardest in the human body.

The only bone not broken so far during any ski accident is one located in your inner ear.

If you break your wrist as an adult it will take you 8 weeks to heal.
A five year old child who breaks their wrist only takes 3 weeks to heal.

What is the Skeletal System?
 it is made up of cartilage and bone, with extra support coming from ligaments and tendons
 Shown here is the nose which is made of cartilage and bone

Purpose?
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 protect and support muscles and organs (i.e.. the brain is protected by the surrounding skull as the heart and lungs are encased by the sternum and rib cage withstand tremendous forces that affect an organism
• remain strong under the stresses of movement ( ex. walking) provide sites of attachment of tendons and muscles, essential for locomotion

What would happen if humans didn't have bones?
You'd be floppy like a beanbag. Could you stand up? Forget it. Could you walk? No way. Without bones you'd be just a puddle of skin and guts on the floor.

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What are bones?
Hard, solid organs that form the skeleton help with support, protection, movement, storage and the production of blood cells ( in bone marrow)
Have blood vessels and nerves supplying them nutrients and information
Within the "alive bone" are blood vessels, nerves, collagen, and living cells including: osteoblasts, osteocytes and osteoclasts
The nonliving, but very important, substances in bone are the minerals and salts. These help makes bones strong!

The Team
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Osteoblasts : bone builders, ( # decreases with age= brittle bones)
Osteocytes help control the mineral balance of the body
Osteoclasts : are mature osteoblasts that have ended their bone-forming careers.
These cells break down bone during normal bone renewal and growth, they are also important in the healing of fractures

There are two types of bone tissue:
1.
Compact bone tissue :
 the hard outer layer of bones is composed of this
 Its name comes from the fact that is has a small amount of gaps and spaces ( is very dense )
 gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton

Compact Bone tissue

Spongy bone tissue
 the spongy interior layer of bone that protects the bone marrow
 Cancellous bone may also be called a spongy bone or trabecular bone
 structurally resembles honeycomb and accounts for about 20% of bone matter in the human body ,but has nearly ten times the surface area of compact bone

What is bone marrow?
Many bones are hollow. Their hollowness makes bones strong and light. It's in the center of many bones that bone marrow makes new red and white blood cells. Red blood cells ensure that oxygen is distributed to all parts of your body and white blood cells ensure you are able to fight germs and disease. Who would have thought that bones make blood!?!

Bone marrow saves lives!
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Can be used to diagnose
Stem cells in donor bone marrow can be used to restore harmed bone marrow cells in cancer patients which are required to produce blood cells

How many bones do humans have?
When you were born you had over 300 bones.
As you grew, some of these bones began to fuse together. The result? An adult has only
206 bones!
But how?

From about 300- 206?
As a fetus your skeleton is composed of mainly cartilage which calcifies into bone with the help of bone building cells and minerals (calcium and phosphate) and salt .
When born you have about 300 bones, but as you grow some fuse thus by the time you hit 25 you are a fully grown adult with 206 bones.
This means that nearly one-third of the bones in our human body will bond together during the period between infancy and adulthood.

Infant Male Female

Types of Bones
 Long bones-
 Short bones-
 Flat bones-
 Irregular Bones-

Fun movie clips!
 http://www.youtube.com/watch?v=7vLAE_P_ u_4&feature=related