Answer to Question #259353 in Cell Biology for Yousef

Question

Hi.We know there are some cells in bone tissue that is called osteoclast. Osteoclasts produce a number of enzymes to cleave and dissolve bone matrix . Now the question is that : why these enzymes don't hurt the Osteoclasts and its membrane? Which function protect osteoclast against these enzymes?

Thanks .

Answer 1

Bone is a mineralized connective tissue that exhibits four types of cells: osteoblasts, bone lining cells, osteocytes, and osteoclasts [1, 2]. Bone exerts important functions in the body, such as locomotion, support and protection of soft tissues, calcium and phosphate storage, and harboring of bone marrow [3, 4]. Despite its inert appearance, bone is a highly dynamic organ that is continuously resorbed by osteoclasts and neoformed by osteoblasts. There is evidence that osteocytes act as mechanosensors and orchestrators of this bone remodeling process [5–8]. The function of bone lining cells is not well clear, but these cells seem to play an important role in coupling bone resorption to bone formation [9].

Bone remodeling is a highly complex process by which old bone is replaced by new bone, in a cycle comprised of three phases: (1) initiation of bone resorption by osteoclasts, (2) the transition (or reversal period) from resorption to new bone formation, and (3) the bone formation by osteoblasts.