Chapter 38: Structure and Function of the Musculoskeletal System

Chapter 38: Structure and Function of the Musculoskeletal System 1. Which component of the bone matrix gives bone its tensile strength? a. Calcium b. Phosphate c. Collagen d. Magnesium ANS: C While calcium, phosphate, and magnesium all play a role in bone formation, collagen is the component of bone matrix that gives bone tensile strength. REF: p. 969, Table 38-1 2. Once their initial function is complete, what do osteoblasts become? a. Osteoclasts b. Osteocytes c. Chondroblasts d. Osteoids ANS: B Osteoblasts are the bone-forming cells. Their primary function is to lay down new bone. Once this function is complete, osteoblasts become osteocytes. Osteoclasts reabsorb bone. Chondroblasts are a part of mNaUtuRreSbIonNeG. OTsBte.oiCdsOaMre part of nonmineralized bone matrix that the osteoblasts work on. REF: p. 970 3. Hydroxyapatite found in bone matrix contains a combination of which molecules in its crystalline structure? a. Calcium and magnesium b. Calcium and phosphate c. Phosphate and magnesium d. Magnesium and hydrogen ANS: B Calcium and phosphate form amorphous (fluid) calcium phosphate compounds that are converted, in stages, to solid hexagonal crystals of hydroxyapatite. Hydroxyapatite does not contain magnesium or hydrogen. REF: p. 972 4. What is the major difference between compact and spongy bone? a. Organization of the structural elements b. Location within the body c. Activating chemicals in each d. Types of minerals in the bone matrix ANS: A The major difference between the two types of tissue is the organization of the elements. The differences in location in the body, chemical activation, or types of minerals contained are not as relevant. REF: pp. 972-973 5. How do blood vessels penetrate into the inner structures of the bone? a. Volkmann canals b. Canaliculi c. Sharpey fibers d. Lamellae ANS: A The outer layer of the periosteum contains blood vessels and nerves, some of which penetrate to the inner structures of the bone through channels called Volkmann canals. Canaliculi are small channels or canals. Sharpey fibers also help hold or attach tendons and ligaments to the periosteum of bones. Concentric layers of bone matrix are called lamellae.