BIOTRAC Science Saturday Activity: Bones
Year 3 Area - Unintentional Injury & Sports Medicine
Insights
Like a house, the human body has a framework. But instead
of wood, the body's framework is made of all the bones in
our skeletal system. There are long bones (arms and legs),
short bones (fingers and toes), flat bones (skull and
sternum), and even tiny bones (in the middle ear). Some
bones, like the ribs, permit respiration and protect vital
organs such as the heart from harm. Others, like the spinal
vertebrae, form the framework to keep us upright as well as
surround and protect the spinal cord.
Unlike a house's framework, however, the
body's framework is alive - bones are living
tissue. From birth until mid- to lateadolescence, bones grow as we do. They
reshape themselves throughout our
lives. Some of the bone cells that
carry on this growth and
"remodeling" work are called osteoblasts
and osteoclasts. Bones grow at special
areas called growth plates.
The outer layer of hard "compact" bone
(the cortex) consists of a system of
tunnels that looks like a miniature
collection of hollow pipes. These tunnels
keep bones lightweight, yet provide the
strength
necessary to support the body. The tunnels
also
allow for the exchange of nutrients and waste products.
Collagen, a protein, gives bones their elasticity while
calcium salts make them hard. Bone marrow, located in the
center of our long bones, makes blood cells.
To develop properly and grow strong, our bones
need calcium, vitamin D, and regular exercise.
Sources of calcium such as milk, yogurt, ice
cream, and broccoli provide the nutrients for
continuous bone building and remodeling. Vitamin D
helps our bodies absorb this calcium through the
gut. Vitamin D comes either from a chemical action of
sunlight on our skin or from fortified milk. Finally,
regular exercise makes bones stronger by stressing them.
When bones are stressed, they respond by fortifying
themselves. This cycle of stress and response to stress
promotes strengthening.
When we don't get enough calcium, vitamin D, and exercise,
our bones deteriorate. For example, young children who are
deprived of calcium and vitamin D may develop a type of
bone weakness called rickets. Older people, particularly
women, may develop a form of weak bones called
osteoporosis.
Prevention of bone weakness is crucial - once weakness
occurs, it may not be reversible. So to have healthy bones
and keep our body's living framework strong and supple, we
must eat foods containing calcium every day, exercise on a
regular basis, and get either a moderate amount of exposure
to sunlight or drink milk fortified with vitamin D.
Food for Thought
What contributes to making and keeping bones strong? - What
would happen if bones didn't grow or stopped growing too
soon? - What are some ways to help with this problem? - How
do bones get so strong? - What does our skeletal system do?
- What keeps us from flopping to the floor like a rag doll?
- What functions do our bones perform besides protecting
our organs? - Why are some of our bones big while others
are very small and delicate? - Do you know how many bones
we have? – What are some functions of these different
bones? - What is our largest bone and what is our smallest?
- What do you think is the most important bone we have and
why?
Vocabulary
Calcium: a mineral that is vital to bone development.
Growth plate: a disk of cartilage along which bones extend
their length or size.
Lacunae: a small space, cavity, or depression; a hollow.
Mineral: an essential element that helps keep our organs
working smoothly.
Osteoblast: a cell that builds or produces bone.
Osteoclast: a cell that absorbs bone under certain
conditions such as fractures.
Osteoporosis: a thinning of bone that occurs with aging or
inactivity.
Rickets: a bone disease of infants or juveniles in which
vitamin D deficiency causes skeletal deformities.
Vitamin D: a vitamin needed for development of healthy
bones and teeth.
It’s all about the Bone-jamins’!
Make an articulated skeleton using yourself as a model.
Materials
poster board
brads, medium and small
glue
scissors
tape measures
metric conversion charts
anatomy book illustration of skeletal system
chalkboard and chalk
string
Paper
Scary. Creepy. Weird. Cool. That's what you may say about
skeletons on Halloween. Now you can easily make one in your
classroom. Close your eyes and think of yourself as a
skeleton. Imagine all your bones from the top of your head
down to your toes. Did you know that when fully grown, you
will have 206 bones in your body?
1. On the chalkboard, list the names of all the bones you
want to include when you make your skeleton. Copy the
list on paper.
2. Next, take measurements of all the bones on your list,
using yourself as a model. Write measurements next to
the appropriate bone on the list.
3. Either working in a small group or individually, start
drawing your bone pieces on your poster board, using
your measurements. Label all your pieces so you will
know which are which. Then, cut out the pieces.
Finally, connect the various bones using brads or
glue.
4. When you have completed your skeleton, insert a string
near the top of its head and hang your masterpiece in
the classroom.
Questions
1. What did you notice about your skeleton that is
different from the real you? How could this skeleton move?
2. What do the brad connectors and your joints have in
common? Why is it necessary to use brads for joining some
bone but not others?
3. What did you notice about the bone sizes? Where are big
bones? Little ones? Why?