Difference Between Chondroblasts and Chondrocytes

Main Difference – Chondroblasts vs Chondrocytes

Chondrocytes and chondroblasts are two types of cells found in cartilages. Chondroblasts are a type of immature cells whereas chondrocytes are a type of mature cells. The main difference between chondrocytes and chondroblasts is that chondroblasts secrete the extracellular matrix of the cartilage whereas chondrocytes are involved in the maintenance of the cartilage. Once the chondroblasts are trapped in the extracellular matrix, which is secreted by the chondroblasts itself, chondrocytes are formed. Chondrocytes are involved in the diffusion of nutrients to the cartilage as well as the repair of the cartilage.

Key Areas Covered

1. What are Chondroblasts
      – Definition, Characteristics, Function
2. What are Chondrocytes
      – Definition, Characteristics, Function
3. What are the Similarities Between Chondroblasts and Chondrocytes
      – Outline of Common Features
4. What is the Difference Between Chondrocytes and Chondroblasts
      – Comparison of Key Differences

Key Terms: Appositional Growth, Cartilage, Chondroblasts, Chondrocytes, Extracellular Matrix, Glycosaminoglycans, Interstitial Growth, Lacunae, Perichondrial Cells

What are Chondroblasts

Chondroblasts are an immature type of cells found in the cartilage. Chondroblasts are also known as perichondrial cells. Chondroblasts are a type of mesenchymal progenitor cells. They secrete the extracellular matrix of the cartilage. The extracellular matrix of the cartilage is composed of collagen, hyaluronic acid, glycoproteins, proteoglycans, and water. Chondroblasts can be found in the perichondrium of the cartilage. Perichondrium is the thin layer of connective tissue, which protects the cartilage. When needed, the chondroblasts are activated by hormones such as growth hormones and thyroid hormones and secrete the extracellular matrix. This increases the size of the cartilage. This type of growth in cartilage is called the appositional growth.

Difference Between Chondroblasts and Chondrocytes

Figure 1: Chondroblasts

The extracellular matrix secreted by chondroblasts can be found in the outer covering of the cartilage. Once chondroblasts are trapped inside the extracellular matrix, the cells become chondrocytes. Chondroblasts are shown in figure 1.

What are Chondrocytes

Chondrocytes are the mature form of the chondrocytes, which are embedded in the self-secreted, extracellular matrix of the cartilage. These cells are formed from chondroblasts, which secrete the extracellular matrix. This extracellular matrix form lacunae in which the chondrocytes are located in. Chondrocytes are the only cell type found in a mature cartilage. The extracellular matrix, which surrounds chondrocytes, are composed of sulfated glycosaminoglycans. The extracellular matrix of the cartilage is maintained by chondrocytes.

Main Difference - Chondroblasts vs Chondrocytes

Figure 2: Chondrocytes

Chondrocytes help the diffusion of nutrients into the cartilage from nearest blood vessels. Moreover, chondrocytes are involved in the interstitial growth of the cartilage by increasing the cell number and secreting more matrix. Chondrocytes secrete proteoglycans, collagen, and elastin fibers. Chondrocytes in lacunae are shown in figure 2.

Similarities Between Chondroblasts and Chondrocytes

Chondroblasts and chondrocytes are two types of cells found in the cartilage.
Both chondroblasts and chondrocytes are involved in the development of the cartilage.

Definition

Chondroblasts: Chondroblasts are cells that actively produce the components of the extracellular matrix.

Chondrocytes: Chondrocytes are cells that secrete the extracellular matrix of a cartilage and become embedded in it.

Formation

Chondroblasts: Chondroblasts are a type of mesenchymal progenitor cells.

Chondrocytes: Chondrocytes are derived from chondroblasts.

Mature/Immature

Chondroblasts: Chondrobalsts are immature cells.

Chondrocytes: Chondrocytes are mature cells.

Role

Chondroblasts: Chondroblasts secrete the components of the extracellular matrix.

Chondrocytes: Chondrocytes are involved in the nourishment and the maintenance of the cartilage.

Type of Growth

Chondroblasts: Chondroblasts are involved in the appositional growth of the cartilage.

Chondrocytes: Chondrocytes are involved in the interstitial growth of the cartilage.

Conclusion

Chondroblasts and chondrocytes are two types of cells found in the cartilage. Both chondroblasts and chondrocytes are involved in the growth of cartilage. Chondroblasts are an immature type of cells, which secrete the extracellular matrix of the cartilage. Once the matrix surrounds the chondroblasts, the cells become chondrocytes. Chondrocytes are mainly involved in the maintenance of the cartilage by providing nutrients. The main difference between chondroblasts and chondrocytes is the maturity and the role each play in the cartilage.

Reference:

1. “Chondroblast.” Wikipedia, Wikimedia Foundation, 13 July 2017, Available here. Accessed 19 Aug. 2017.
2. “Chondrocytes: Definition & Function.” Study.com, Available here. Accessed 19 Aug. 2017.

Image Courtesy:

1. “Diagram of cartilage cells called chondroblasts CRUK 032” By Cancer Research UK – Original email from CRUK, (CC BY-SA 4.0) via Commons Wikimedia
2. “Hypertrophic Zone of Epiphyseal Plate” By Robert M. Hunt – Own work (Public Domain) via Commons Wikimedia