The recent “Got Milk?” advertising campaign inspired thoughts of strong, healthy bones in a new generation of consumers. However, physicians argue that dairy products do not build higher bone densities on their own, but that exercise, sunlight, and a diet rich in fruits and vegetables are also needed.

View a second image of a human bone thin section.

View a third image of a human bone thin section.

Bone is a rigid body tissue that consists of cells embedded in a hard intercellular substance. Collagen and calcium phosphate are the two principle components of the material and distinguish bone from other hard tissues, such as chitin and enamel. The exterior layer of bone tissue, known as the cortex, is smooth, dense, and continuous. The interior of bone consists of a network of intersecting plates and spicules that vary in proportion and enclose spaces filled with blood vessels and marrow.

Although all of the bones in the human body have the same basic structure, they differ in their external shape and size. Bones may be small and intricate, like those in the inner ear, or long and straight, similar to the femur. Each of the approximate 200 bones of the human body is designed to accomplish a particular need. Some of their various functions include structural support during mechanical action, protection of soft organs, and mineral storage.