When cartilage is being formed in an embryo mesenchyme cells come together. These cells then start to secrete a matrix. This action pushes the cells apart and the end result is that the chondrocytes become isolated in lacunae . Cartilage can grow by adding more tissue to the outside of the existing cartilage or by expanding internally. Once the cells are isolated in lacunae they quit dividing, but we may see 2 or 4 cells in a lacuna.
Cartilage is the skeleton of vertebrate embryos and some fish.
Found in shark jaws. The mesenchyme cells congregate in strands at the site of the future bone. These strands produce collagen and make a frame. At this point the mesenchyme cells have differentiated into osteoblasts which deposit calcium salts. The cells build a matrix and become trapped in lacunae.