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.
Ends: The ends of long bone are actually not compact as the shaft. They are made up of spongy (cancellous) bone. In cancellous bone the bone substance to bone spaces ratio is a smaller quantity.This means that there is little bony tissue and more empty spaces in this portion of the bone.he cortex is actually the compact part of the long bone. The strength of the bone which makes it capable to withstand all the stresses is mainly due to this cortex. In the cortex the ratio of bone substance to bone spaces is a large quantity.