ribonucleic acid, RNA (noun). (biochemistry) a long linear polymer of nucleotides found in the nucleus but mainly in the cytoplasm of a cell where it is associated with microsomes; it transmits genetic information from DNA to the cytoplasm and controls certain chemical processes in the cell.
Osteocytes â mature osteoblasts. Osteoclasts â bone-destroying cells. Compact bone A structural unit of a compact bone is called an osteon (or Haversian system). Osteon â cylindrical structure oriented parallel to bone's long axis.Osteon consists of hollow tubes, one inside the other, called lamella.steocytes â mature osteoblasts. Osteoclasts â bone-destroying cells. Compact bone A structural unit of a compact bone is called an osteon (or Haversian system). Osteon â cylindrical structure oriented parallel to bone's long axis.Osteon consists of hollow tubes, one inside the other, called lamella.
The osteon is the primary structure that makes up the hard outer layer of bones, which is generally known as â cortical bone .â Cortical bone, or compact bone, is dense, mature bone found in vertebrates such as mammals, amphibians, reptiles, and birds.It is this dense hard layer that gives a person or animal strength.he osteon is the primary structure that makes up the hard outer layer of bones, which is generally known as â cortical bone .â Cortical bone, or compact bone, is dense, mature bone found in vertebrates such as mammals, amphibians, reptiles, and birds. It is this dense hard layer that gives a person or animal strength.