Differences between Osteoblast and Osteoclast

All living organisms are made up of cells, which are the fundamental building blocks. As cells are bundled in inconspicuous and immediately identifiable ways, they are identified as building blocks. There are various types of cells in various sections of the human body, each with its own style of operating in the process. The types of bone cells are osteoblast and osteoclast. However, they act differently in the human body.

The bone remodeling process contributes to better bone maintenance and mineral management. Calcium and phosphorus are two of the most essential nutrients for bone health.

This page explains the distinctions between osteoblast and osteoclast in detail. Take the time to read it and learn about their similarities.

Osteoblast and Osteoclast

What is Osteoblast?

The osteoblast is a single nucleus cell that works as part of a group during bone production and mineralization. The bone cell is essential throughout the first stages of bone growth and remodeling.

The cells are found in a densely packed cluster on the surface of the bones. The bone cells develop from osteogenic cells on the bone’s outer surface, known as the periosteum.

Many cell products are produced by the bone cell that aid in bone growth. Growth factors, collagen, hormones, and enzymes are examples of cell products.

The osteoblast is surrounded by a growth matrix during the bone creation process, and the cells become imprisoned in Lacuna.

The trapped osteoblast cells grow into osteocytes, which serve as a medium of communication between the bone surface and the canaliculi, which receive nutrients.

Function of Osteoblast

Osteoclasts are multinucleated cells that are in charge of bone resorption. They’ve created a machine that dissolves crystalline hydroxyapatite and degrades organic bone matrix rich in collagen fibers. When osteoclasts begin bone resorption, they become polarized and develop three different membrane domains: a ruffled border, a sealing zone, and a functional secretory domain. At the same time, the cytoskeleton undergoes substantial reorganization. The actin cytoskeleton generates an attachment ring at the sealing zone, the membrane domain that ties the resorbing cell to the bone matrix, throughout this process. The ruffled border appears inside the sealing zone and resembles late endosomal membrane in some ways. Extensive vesicle transport to the ruffled border supplies hydrochloric acid and proteases to the resorption lacuna, which is located between the ruffled border and the bone surface. Acid dissolves crystalline hydroxyapatite in this extracellular compartment, while a protease combination destroys the organic matrix. Endocytosed collagen and other matrix component breakdown products are carried within the cell and exocytosed via a functioning secretory domain. This transcytotic pathway permits osteoclasts to extract substantial amounts of matrix-degradation products while remaining tightly attached to the underlying bone. It also allows for intracellular processing of degradation products as they travel through the cell.

What is Osteoclast?

The osteoclasts are bone cells that secrete acid and collagenase enzymes to dissolve mineral deposits on the osteoblast.

These cells are often present on the surface of the bones, and the materials that are broken down are absorbed into the bloodstream.

The enzymes secreted by osteoclasts trigger the creation of Howship lacunae, which are small depressions on the bone. This is where the osteoclast usually resides.

These bone cells are generally produced from bone marrow as well as circulating cells like monocytes and macrophages.

Osteoclasts are multinucleated cells with 200 nuclei per cell. Microvilli on the surface of bone cells generate the brush-like structure for bone resorption.

Acid phosphatases are secreted by bone cells and are responsible for the dissolution of calcium, collagen, and phosphorus in osteoclasts.

Phosphorus and calcium are later released into the bloodstream as a result of bone demineralization. The good news is that osteoclasts do not attack the osteoid.

Function of osteoclast

An osteoclast is a big multinucleated cell that dissolves and absorbs bone. Bone is a dynamic tissue that is constantly being broken down and reconstructed in response to pressures such as structural stress and the body’s calcium demand. The osteoclasts are the agents responsible for the ongoing breakdown of bone. Osteoclasts live in little depressions on the bone’s surface known as Howship lacunae, which are hypothesized to be created by the osteoclasts’ enzymes eroding the bone. Osteoclasts are generated by the fusing of many cells derived from blood circulating monocytes. These are then produced from bone marrow. Osteoclasts can have up to 200 nuclei, but most have just 5 to 20. The cell’s active zone is defined by a ruffled, or brush-like, border formed by many minute projections (microvilli) that extend into the bone’s surface. Osteoclasts produce a number of enzymes, the most important of which is acid phosphatase, which dissolves both organic collagen and the bone’s inorganic calcium and phosphorus. Mineralized bone is first fragmented; the osteoclast then engulfs and digests the fragments within cytoplasmic vacuoles. Calcium and phosphorus are released into the bloodstream as a result of the breakdown of mineralized bone. Unmineralized bone (osteoid) is immune to osteoclastic resorption.

Key Differences Between Osteoblast and Osteoclast

  • The osteoblast is responsible for bone synthesis and mineralization, whereas the osteoclast is responsible for bone breakdown and resorption.
  • Osteoblasts are solitary cells that function in groups, whereas osteoclasts are multinucleated cells with approximately 200 nuclei per cell.
  • Osteoblasts develop from osteogenic cells, whereas osteoclasts form from bone marrow, macrophages, and monocytes.
  • Osteoblasts are formed from mesenchymal osteoprogenitor cells, which promote bone remodeling, whereas osteoclasts are derived from hematopoietic cells, which promote bone resorption.
  • When compared to osteoblast cells, osteoclast cells are bigger.
  • When compared to osteoblasts, osteoclast cells feature more organelles such as mitochondria, vacuoles, and lysosomes.
  • Osteoblast cells produce protein osteoid, whereas osteoclast cells do not produce any proteins.
  • The alkaline and phosphatase enzymes are abundant in osteoblast cells, whereas the acid, tartrate-resistant, and phosphatase enzymes are abundant in osteoclast cells.
  • The phagocytic-like process is present in osteoclast cells but not in osteoblast cells.
  • Osteocytes are the ultimate product of osteoblast cells, whereas osteoclasts have no end result.

 Similarities Between Osteoblast and Osteoclast

  • They are both bone cells.
  • Both participate in the bone remodeling process.
  • Both aid in bone regeneration.
  • Both cells include a nucleus.
  • They are both connective tissues.
  • Both can be present in bone.
  • Both cells are metabolically active.


Osteoblasts and osteoclasts are two types of bone cells with separate functions. Osteoblast and osteoclast are the two major cells engaged in such processes. Osteoblasts are the primary cells responsible for bone production, as well as the integrity and shape of bone tissue. Osteoclasts are the cells that tear down old bone tissue. They generate monocytes in the blood and many types of tissue macrophages. The primary distinction between the two is their role in the bones. The major distinction between osteoblast and osteoclast is hence the function of each kind of bone cell in bone remodeling.