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TABLE 7.1 Summary of Cartilage Features
Features	Hyaline Cartilage	Elastic Cartilage
Location	Fetal skeletal tissue, epiphyseal plates, articular surface of synovial joints, costal cartilages of rib cage, cartilages of nasal cavity, larynx (thyroid, cricoid, and arytenoids), rings of trachea, and plates in bronchi	Pinna of ear (Eustachian tube), auditory canal, epiglottis, and vocal folds
Function	Resists compression Provides cushioning, smooth, and low-friction surface for joints Provides structural support in respiratory system (larynx, trachea, and bronchi) Forms foundation for development of fetal skeleton and further endochondral bone formation and bone growth	Provides flexibility and elasticity
Presence of perichondrium	Yes (except articular cartilage and epiphyseal plates)	Yes
Undergoes calcification	Yes (e.g., during endochondral bone formation, during aging process)	No
Main cell types present	Chondroblasts and chondrocytes	Chondroblasts and chondrocytes
Characteristic features of extracellular matrix	Type II collagen fibrils and aggrecan monomers (the most important proteoglycan)	Type II collagen fibrils and aggrecan monomers
Growth	Interstitially and appositionally, very limited in adults
Repair	Very limited capability, commonly forms a scar, resulting in fibrocartilage formation

3598 3599 HYALINE CARTILAGE 3600 3601 3602 3603 Hyaline cartilage is distinguished by a homogeneous, amorphous matrix. 3604 3605 The matrix of hyaline cartilage appears glassy in the living state, hence the name hyaline 3606 [Gr. hyalos, glassy]. Throughout the cartilage matrix are spaces called lacunae. Located 3607 within these lacunae are the chondrocytes. Hyaline cartilage is not a simple, inert, 3608 homogeneous substance but a complex living tissue. It provides a low-friction surface, 3609 participates in lubricating synovial joints, and distributes applied forces to the 3610 underlying bone. Although its capacity for repair is limited, under normal circumstances, it 3611 shows no evidence of abrasive wear over a lifetime. An exception is articular cartilage, 3612 which, in many individuals, breaks down with age (Folder 7.1). The macromolecules of hyaline 3613 cartilage matrix consist of collagen (predominantly type II fibrils and other cartilage- 3614 specific collagen molecules), proteoglycan aggregates containing GAGs, and multiadhesive 3615 glycoproteins (noncollagenous proteins). Figure 7.2 illustrates the relative distribution of 3616 the various components that constitute cartilage matrix. 3617 3618 3619 ![Two vertically stacked, shaded cylinders display proportional segments labeled with percentages and component names like collagen and proteoglycans.](https://cdn.orris.care/cdss_images/0ff502c9c22dabafcd4782396514d0319f8f4fa72e360fa2e8a72e8ea506700f.png) 3620 3621 *FIGURE 7.2. Molecular composition of hyaline cartilage. Cartilage's net weight is 60% - 80% 3622 intercellular water, which is bound by proteog [... Output truncated due to length. 3632 tokens/14151 characters removed ...]