Chapter 12

The formation of blood cells occurs within what component of the bones?

There are four critical functions of bones: protection of internal organs, support of the body, blood cell production, and regulation of internal calcium concentration. Discuss how bones conduct each of these four tasks.

What are the structural and functional differences between the diaphysis and the epiphysis locations within long bones?

Spongy bone can withstand stresses that arrive from multiple directions, whereas compact bone can normally withstand stresses in only one direction. Why is there this difference and what structures account for this difference?

What are the functions of the four types of bone cells?

Calculate the change in molecular volume of the synovial fluid if the formation rate of synovial fluid by the synovial membrane is \(6.5 \mu \mathrm{g} / \mathrm{h} / \mathrm{cm}^{2}\) and by the cartilage is \(73 \mathrm{ng} / \mathrm{h} / \mathrm{cm}^{2}\). Assume that the synovial membrane area is \(15 \mathrm{~mm}^{2}\) and that of the cartilage is \(25 \mathrm{~mm}^{2}\). The degradation rate of the synovial fluid is \(23 \mathrm{ng} / \mathrm{h}\), and the flux of synovial fluid out of the membrane is \(0.97 \mu \mathrm{g} / \mathrm{h}\).

Calculate the stress on the cartilage and the change in length of cartilage, assuming that the force on the cartilage is \(9875 \mathrm{~N}\) and that the diameter of the cartilage is \(2 \mathrm{~cm}\) (assume that the cartilage has a circular area). The cartilage has a thickness of \(1.5 \mathrm{~mm}\) and an elastic modulus of \(250 \mathrm{MPa}\).