Thermo-electro-elastic bone remodelling

Abstract

In Chapters 3 and 4, the multi-field theories of thermo-electro-elastic and thermomagneto-electro-elastic problems were presented. Applications of the theory to bone remodelling are described in this chapter. Bone is a kind of dynamically adaptable material. Like any other living system, it has mechanisms for repair and growth or remodelling, and mechanisms to feed its constituent parts and ensure that any materials needed for structural work are supplied to the correct area as and when required. These bone functions are performed via three types of bone cell: osteoblast, osteoclast, and osteocyte. Osteoblasts are cells that form new bone and are typically found lining bone surfaces that are undergoing extensive remodelling. Osteoclasts are large, multinucleated, bone-removing cells. Their function is to break down and remove bone material that is no longer needed or that has been damaged in some way. The third cell type is the osteocyte. Osteocytes, called the bone “sensor cells”, are responsible for sensing the physical environment to which the skeleton is subjected. Osteocytes are characterized by many protoplasmic processes, or dendrites, emanating from the cell body. These cell dendrites form a communication network with surrounding cells, other osteocytes, osteoblasts, and possibly osteoclasts, which passes the signals from the osteocytes that control the action of osteoblasts osteoclasts. The activities of these three cell populations, and numerous other biological and biochemical factors, are coordinated in a continuous process throughout our lives to maintain a strong, healthy skeleton system.