Chapter 3. Cartilage
What is the molecular basis for shock absorption within articular cartilage?
A. Attachment of chondrocytes to type I collage fibers
B. Binding of anions by glycosaminoglycans
C. Cross-linking of type I collagen fibers in the perichondrium
D. Electrostatic interactions of proteoglycans with type IV collagen
E. Hydration of glycosaminoglycans in proteoglycan aggregates
The answer is E: Articular cartilage is composed of hyaline cartilage. The mechanical properties of hyaline cartilage, such as its ability to function as a shock absorber, result from complex interactions among the proteoglycan and collagen networks, as well as the large amount of water bound by these components. The major fiber in hyaline cartilage is type II, not type I, collagen. Articular cartilage lacks a perichondrium.
Which cartilaginous structure will be most severely affected by defective synthesis of type I collagen?
A. Cartilage rings in the trachea
C. Epiphyseal growth plates
The answer is D: The matrix of all types of cartilage contains type II collagen. In addition, the matrix of fibrocartilage, which is found in intervertebral discs and the pubic symphysis contains type I collagen fibers.
Which of the following constituents of cartilage is most responsible for interstitial growth?
E. Proteoglycan aggregates
The answer is B: Interstitial growth of cartilage occurs by the division of resident chondrocytes and their production of additional matrix. Interstitial growth in the epiphyseal plates lengthens long bones and is the mode by which articular cartilage is maintained throughout life.
Cartilage is a specialized type of connective tissue, composed of cells, fibers, and ground substance. What is one functionally important difference between the composition of cartilage and connective tissue proper?
A. Cartilage is avascular, whereas connective tissue proper is vascularized
B. Cartilage cells are not mitotically active, whereas cells in connective tissue proper divide frequently