Bone Cells: What are they? Origin, Types and Local Regulators

They are the different cellular structures found in bones.

A cell is the basic building unit of any tissue or organ. Like other organs, bone is also made up of these smaller units that are arranged to form the structure that we see outward.

These cells have the function of forming hard and specialized tissues that in turn fulfill the anatomical function of supporting the body and containing some vital organs.

Origin of bone cells

The term mesenchymal refers to cells that were deep within the embryo during early development; some of them remain in the bone marrow but do not form blood cells. Hematopoietic cells form the liquid part of the bone marrow and some of them circulate with the blood.

Local regulators

Bone cells make molecules (usually proteins) that communicate with other cells.

These molecules are called growth factors and cytokines. They act in nearby cells and are therefore considered local regulators. These factors control cell division (proliferation), differentiation, and survival.

Types

The following types of bone cells are found in bone. Different types of bone cells are programmed for types of functions.

  • Osteoclastos.
  • Osteoblastos.
  • Osteocitos.
  • Coating cells.

All of these cell names begin with “OSTEO” because that’s the Greek word for bone.

Osteoclastos

They are large cells that dissolve bone. They come from the bone marrow and are related to white blood cells.

They are formed from two or more cells that fuse with each other, so osteoclasts usually have more than one nucleus. They are found on the surface of the bone mineral next to the dissolving bone.

Osteoblastos

They are the cells that form new bone. They also come from the bone marrow and are related to structural cells . They have only one core. Osteoblasts work as a team to build bone.

They make new bone called “osteoid” which is made from bone collagen and other proteins. They then control the deposition of calcium and minerals. They are found on the surface of the new bone.

When the osteoblast team has finished filling a cavity, the cells become flat and look like pancakes. They line up on the surface of the bone. These old osteoblasts are also called lining cells .

They regulate the passage of calcium in and out of the bone, and respond to hormones by producing special proteins that activate osteoclasts.

Osteocitos

They are cells within the bone. They also come from osteoblasts. Some of the osteoblasts become osteocytes as new bone forms, and the osteocytes surround themselves with new bone.

However, they are not isolated because they send out long branches that connect with the other osteocytes.

These cells can detect pressures or cracks in the bone and help direct where the osteoclasts will dissolve the bone.

Other bone cells

Other cells are disclosed, including reticular cells that are found within the mesh-like structure of bone marrow, and possess osteogenic and hematopoietic potencies; endosteal cell that can be connected to tissue cells or to resting osteoblasts and fibroblasts with a basophilic cytoplasm and round nucleus.