MICROANATOMY

Detailed explanation-1: -As they divide, the chondrocytes secrete a cartilage-specific extracellular matrix. The outermost cells become the perichondrium that ensheaths the cartilage. In the fourth phase, the chondrocytes stop dividing and increase their volume dramatically, becoming hypertrophic chondrocytes (Figure 1D and Figure 2).

Detailed explanation-2: -This growth within a tissue is called interstitial growth. Most of the chondrocytes in the zone of calcified matrix, the zone closest to the diaphysis, are dead because the matrix around them has calcified, restricting nutrient diffusion.

Detailed explanation-3: -1) As the cartilage enlarges, chondrocytes near the center of the shaft increase greatly in size, the matrix is reduced to a series of small struts that soon begin to calcify, and the enlarged chondrocytes die and disintegrate, leaving cavities within the cartilage.

Detailed explanation-4: -It is generally thought that during endochondral ossification, hypertrophic chondrocytes-at their terminal state of chondrocyte maturation-undergo cell death and are subsequently replaced by bone.