Milia are small, white cysts commonly seen around the cheeks. Overview. Milia are commonly found on the skin of people of all ages. They are formed when keratin (a substance produced by the skin) becomes entrapped beneath the outer layer of the skin, forming a tiny cyst. An individual milium (the singular of milia) is formed at the base of a hair follicle or sweat gland.
The basic first level structure of cortical bone are osteons. Trabecular bone is much more porous with porosity ranging anywhere from 50% to 90%. It is found in the end of long bones (see picture above), in vertebrae and in flat bones like the pelvis. Its basic first level structure is the trabeculae. III.
Individual cells cannot make bone, and the group of organized osteoblasts together with the bone made by a unit of cells is usually called the osteon; the basis of this is discussed in Organization and ultrastructure of osteoblasts below.uring active bone formation, the surface layer of osteoblasts consists of cuboidal cells, called active osteoblasts. When the bone-forming unit is not actively synthesizing bone, the surface osteoblasts are flattened and are called inactive osteoblasts.