This chapter should help the student to:

• Know the similarities and differences among the three cartilage types.
  
• Relate the functions of the three cartilage types to their structure and location.
  
• Know the steps in the histogenesis and growth of cartilage.
  
• Relate chondrocyte ultrastructure to the synthesis and maintenance of extracellular matrix.
  
• Recognize the cartilage type present in a micrograph and identify its components.

1. Compare the three types of cartilage in terms of:

1. 
   

   Type, amount, and arrangement of cells, fibers, and ground substance (Table 7–1)

   
   
2. 
   

   Location in the body (Table 7–1)

   
   
3. 
   

   Histogenesis (II.A.3, B.2, and C.2)

   
   
4. 
   

   Function (Table 7–1)

2. Sketch a typical proteoglycan aggregate of cartilage ground substance (Fig. 7–1). Label the hyaluronan, link protein, core protein, chondroitin sulfate, and proteoglycan. Indicate which are GAGs.

3. Compare capsular (territorial) matrix and intercapsular matrix in terms of location, composition, and staining properties (II.A.2).

4. Describe the structure and function of the perichondrium (I.B; II.A.2).

5. List the functions of chondrocytes and name the organelles involved in each function (I.C).

6. List the factors known to increase or decrease the synthesis and secretion of sulfated GAGs (e.g., chondroitin sulfate) by chondrocytes (II.A.4).

7. Name the types of growth that occur in hyaline cartilage and compare them in terms of the location of their dividing cells and their importance in expansion of girth, replacement of worn articular cartilage, and bone lengthening at the epiphyseal plate (II.A.4).

8. What is the major structural difference between articular and other hyaline cartilage (II.A.6)?

9. How are the chondrocytes of articular cartilage supplied with nutrients and oxygen (I.B; II.A.2)?

10. What process, other than cell division, increases cartilage mass during growth (II.A.4)?

11. Describe the origin of chondrocytes that fill and repair a cartilage fracture (II.A.5).

12. Describe an intervertebral disk (III.A and B) in terms of location, function, the tissue in its annulus fibrosus and nucleus pulposus, and the latter’s embryonic origin.

I. General Features of Cartilage

Cartilage is a skeletal connective tissue characterized by firmness and resiliency. It forms the fetal skeleton and persists where its mechanical properties are needed. Most fetal cartilage is replaced by bone.

A. Composition

Like all connective tissues, cartilage consists of cells, fibers, and ground substance. The extracellular matrix predominates and confers its mechanical properties. Type II collagen is a characteristic cartilage matrix component. The abundant ground substance is firm and gel-like. Cartilage cells are termed chondrocytes.

B. Blood Supply