Chapter 43: Structure and Function of the Musculoskeletal System

Chapter 43: Structure and Function of the Musculoskeletal System

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. Which bone cells produce osteocalcin when stimulated by 1,25-dihydroxyvitamin D and synthesize osteoid?

a.	Osteoclasts	c.	Fibrocytes
b.	Osteocytes	d.	Osteoblasts

 

 

ANS:  D

Osteoblasts are cells derived from mesenchymal stem cells and produce several substances, including osteocalcin, transforming growth factor–beta (TGF-b) (a growth inhibitor for many cells), macrophage colony–stimulating factor, receptor activator of nuclear factor kappa-B ligand, osteoprotegerin (OPG), and bone matrix when stimulated by 1,25-dihydroxyvitamin D. This statement is not true of the other options.

 

PTS:   1                    REF:   Page 1514

 

2. What happens to the original bone during the second phase of bone remodeling?

a.	The original bone is replaced.	c.	The original bone is resorbed.
b.	It hardens.	d.	It is synthesized.

 

 

ANS:  C

The distribution of these apoptotic osteocytes provides osteoclasts with information about where to begin resorbing damaged bone. In the second phase of remodeling (resorption), the osteoclasts form a cutting cone that gradually resorbs bone, leaving behind an elongated cavity termed a resorption cavity. This selection is the only option that accurately describes what happens when bone is resorbed.

 

PTS:   1                    REF:   Pages 1519-1520

 

3. Which cells function to maintain bone matrix?

a.	Osteoclasts	c.	Osteoblasts
b.	Osteocytes	d.	Osteophytes

 

 

ANS:  B

Osteocytes help synthesize and replace needed elements of the matrix by signaling osteoclasts and osteoblasts to resorb and form new bone. This selection is the only option that performs that function.

 

PTS:   1                    REF:   Pages 1514-1515

 

4. Which bone cells are large and multinucleated and contain lysosomes filled with hydrolytic enzymes?

a.	Osteoblasts	c.	Osteocytes
b.	Osteoclasts	d.	Fibrocytes

 

 

ANS:  B

Osteoclasts are the major resorptive cells of bone. They are large multinucleated cells with a short life span and contain lysosomes (digestive vacuoles) filled with hydrolytic enzymes. This selection is the only option that is described in this manner.

 

PTS:   1                    REF:   Page 1515

 

5. Which bone cell secretes hydrochloric acid to help dissolve bone minerals and collagenase, thus aiding in the digestion of collagen?

a.	Osteocytes	c.	Osteoclasts
b.	Osteoblasts	d.	Osteophytes

 

 

ANS:  C

Only osteoclasts bind to the bone surface of cell attachment proteins called integrins. They bring about resorption of bone by secreting hydrochloric acid and cathepsin K (a protease enzyme) that help dissolve bone minerals and collagenase, which aids in digesting collagen, along with the action of cytokines.

 

PTS:   1                    REF:   Page 1515