Osteoblasts are bone-forming cell, osteoclasts resorb or break down bone, and osteocytes are mature bone cells.

Mechanotransduction is the process by which physical forces are converted into biochemical signals that are then integrated into cellular responses. It plays a crucial role in bone repair and regeneration and thus has attracted a great deal of interest from researchers in various fields.

The skeleton is a metabolically active organ that undergoes continuous remodeling throughout life. Bone remodeling involves the removal of mineralized bone by osteoclasts followed by the formation of bone matrix through the osteoblasts that subsequently become mineralized.

Osteoclasts are the cells that degrade bone to initiate normal bone remodeling and mediate bone loss in pathologic conditions by increasing their resorptive activity. They are derived from precursors in the myeloid/ monocyte lineage that circulate in the blood after their formation in the bone marrow.

Failure to remodel bone can result in excessive microdamage burden, accumulation of advanced glycation end products (AGEs), and hypermineralization. Microdamage, left unrepaired, reduces the residual strength and stiffness of bone, and can lead to stress fractures.

Osteoprogenitor cells, also known as osteogenic cells, are stem cells located in the bone that play a prodigal role in bone repair and growth. These cells are the precursors to the more specialized bone cells (osteocytes and osteoblasts) and reside in the bone marrow.

Bone turnover rates differ depending on the bone and the area within the bone. There are four stages in the repair of a broken bone: 1) the formation of hematoma at the break, 2) the formation of a fibrocartilaginous callus, 3) the formation of a bony callus, and 4) remodeling and addition of compact bone.

Normal bone is always undergoing remodeling. This remodeling removes old bone tissue and replaces it with new bone tissue. The remodeling cycle, removing and building tissue, continues throughout life and is typically “in balance” to maintain healthy bone.

Osteoblast and osteoclast are the two main cells participating in those progresses (Matsuo and Irie, 2008). Osteoclasts are responsible for aged bone resorption and osteoblasts are responsible for new bone formation (Matsuoka et al., 2014). The resorption and formation is in stable at physiological conditions.

What is the role of osteoclasts in the endosteum during long bone growth? They proportionally increase the size of the medullary cavity as the bone grows to prevent the weight of the growing skeleton from becoming too heavy. All bone surfaces in the body are covered by the periosteum.

Keys to bone balance Parathyroid hormone (PTH) is an important contributor to the bone remodeling process. High levels of PTH can activate osteoclasts and cause excessive bone breakdown. Calcium in your blood triggers the release of PTH. Low calcium levels in the blood, or hypocalcemia, can cause high levels of PTH.

The option that is not true is E) Osteocytes have 50 or more nuclei. Osteocytes, when mature, only have a single nucleus. It would not particularly make sense for an osteocyte to have 50 nuclei as they are largely depository/secretory cells that repair and then deposit proteins in the bone.

Mechanotransduction in development has been proposed based on effects of stretching embryos in vitro and altering mechanical forces in vivo ( Beloussov, 1980, Beloussov et al., 1988 ).

Bone is shaped by forces from gravity and muscle contraction. Hearing and touch are based on neural responses to pressure. Inflation and deflation of the lungs regulate their physiology. Coordinated growth of tissues is guided by mechanical forces, and failure of these mechanisms contributes to cancer.

Mechanotransduction may regulate the formation of left-right asymmetry in mammals through fluid flow within the ventral node.