May 7, 2012
Support and Protection:
Bones provide structural support and serve as a framework for the entire body
Bones also protect many delicate tissues and organs from injury and trauma.
The rib cage protects the heart and lungs
the cranial bones enclose and protect the brain
the vertebrae enclose the spinal cord
the pelvis cradles some digestive, urinary, and reproductive organs.
Lever for Muscles
The bones of the body serve as lever arms and the muscles provide the force; together they produce limb
and total body movement
The direction and magnitude of the forces generated by the skeletal muscles can be altered by bones.
Potential movements range from powerful contractions needed for running and jumping to delicate,
precise movements required to remove a splinter from the finger
Tissues in the middle of some bones (sternum, ilium) serve as the location for the production of blood
Blood cells are produced in a connective tissue called red bone marrow, which is located in some spongy
Red bone marrow contains stem cells that form all of the formed elements in the blood.
Storage for Minerals
More than 90% of the body’s reserves of the minerals calcium and phosphate are stored and released by
Calcium is an essential mineral for such body functions as muscle contraction, blood clot-ting, and nerve
Phosphate is needed for ATP utilization, among other things. When calcium or phosphate is needed by
the body, some bone connective tissue is broken down, and the minerals are released into the
Potential energy in the form of lipids is stored in yellow bone mar-row, which is located in the shafts of
long bones. Bone Terminology
Osteoblast: bone forming cell
Osteoclast: Cells that break down and
help to remodel and reshape bone
Osteocyte: Mature bone cells
Compact Bone: Densely packed bone on
the external surface; like a she