Page 376 - Microsoft Word - LessonPlan-Overview.doc
P. 376
Unit 19: Biology Part 2 Page 31 of 137
and the ribs protect the heart
and lungs.
Movement: The bones work
in concert with the muscles
to give us the ability to
move.
Making Blood Cells: Certain
parts of certain types of
bones make blood cells.
Storage: Bones store calcium
and phosphorus (mostly
calcium).
Figure 4 Cross-sections of
What are bones? human bones.
Bones are made up of several Growth
parts; bone marrow (red and
yellow), spongy bone, compact Bones begin growing very early,
bone, and the periosteum. and stop growing between the ages
of 18-25. At about eight weeks of
Bone marrow makes blood cells. development, we form a skeleton
Red blood cells are made in the of cartilage and other connective
red marrow, while white blood tissues. As we grow up, the
cells are made in the yellow cartilage becomes bone. Normally,
marrow. When babies are born we have all of our bones by our
they only have red marrow. early twenties. We still keep some
of the cartilage in areas like our
Spongy bone is a light, spongy nose and ears.
type of bone found inside bones.
Movement
Compact bone, on the other
hand, is hard and makes up the Joints are essential in how we
outer layer of bones. The compact move. Bones work as levers and
bone layer is covered by a thin the joints work as the fulcrums—
white membrane called the making our movement easier.
periosteum. Some joints are fixed; for example,
many in the skull. Some allow only
little movement; for example, the
© 2011 Supercharged Science www.ScienceLearningSpace.com
778
