Key Difference – Chondroblasts vs Chondrocytes
Cartilage is a specialized connective tissue found in many places of the body. Chondrogenesis is the process which forms cartilage from mesenchyme tissue. There are two main cell types in the cartilage known as chondroblasts and chondrocytes. Chondroblasts are actively dividing immature cells which form extracellular matrix and the chondrocytes. Chondrocytes are the differentiated cells which are involved in the diffusion of the nutrients, maintenance, and repair of the extracellular matrix of the cartilage. The key difference between chondrocytes and chondroblasts is that chondroblasts are immature cartilage cells found near the perichondrium while chondrocytes are mature cartilage cells found embedded within the extracellular matrix.
CONTENTS
1. Overview and Key Difference
2. What are Chondroblasts
3. What are Chondrocytes
4. Side by Side Comparison – Chondroblasts vs Chondrocytes
5. Summary
What are Chondroblasts?
Chondroblasts, also called chondroplasts, are immature cells, that are essential for cartilage development. They are located along the edges of the cartilage under the perichondrium where the cell division occurs as two oppositional areas. Chondroblasts are also known as perichondrial cells or mesenchymal progenitor cells, which give rise to chondrocytes and components of the extracellular matrix. Chondroblasts mainly secrete type two collagen and other types of extracellular matrix components.
Figure 01: Chondroblasts in cartilage tissue
What are Chondrocytes?
Chondrocytes are specialized cells found in the cartilage matrix cavities called lacunae. They are matured and differentiated cells of chondroblasts. The major function of the chondrocyte is to synthesis, maintain and remodel the extracellular matrix of the cartilage. Extracellular matrix is composed of equal proportions of collagen fibrils and proteoglycans. These two components are produced by the chondrocytes in the cartilage. However, chondrocytes are relatively inert cells with low regenerative capacity.
Figure 02: Chondrocytes in the cartilage
Cartilage does not have blood vessels or nerves. Therefore, to maintain the structure and function of the cartilage, chondrocytes should obtain nutrients from the matrix. Nutrients are supplied to the chondrocytes by a process called diffusion. Chondrocytes malfunction can lead to a disease called osteoarthritis. It is a cartilage degenerative disease caused due to the breakage of tissue homeostasis.
The flexibility of the cartilage is decided by the number of chondrocytes present in the cartilage. There are three types of cartilages known as hyaline, elastic and fibrocartilage as shown in figure 03.
Figure 3: Cartilage types
What is the difference between Chondroblasts and Chondrocytes?
Chondroblasts vs Chondrocytes |
|
| Chondroblasts are a type of cells found in the cartilage which are responsible for the cartilage development. | Chondrocytes are a type of specialized cells found in cartilage which are responsible for cartilage maintenance. |
| Location | |
| These are located in the two oppositional growing areas of the cartilage under the perichondrium | These are found embedded within the lacunae. |
| Maturity | |
| These are immature cells which are actively dividing. | These are immature cells which are inactive and differentiated. |
| Usage | |
| Chondroblasts produce chondrocytes and extracellular matrix of the cartilage. | Chondrocytes produce components of the extracellular matrix and maintain the cartilage structure and function. |
| Chondrocyte Formation | |
| These are the progenitor cells of chondrocytes | Chondrocytes are formed from chondroblasts |
Summary – Chondroblasts and Chondrocytes
Chondroblasts and chondrocytes are two types of cells found in the cartilage. Chondroblasts are actively dividing immature cells located near the perichondrium of the cartilage. They are the actual cells which create the cartilage. Chondroblasts are the progenitors of the chondrocytes and extracellular matrix of the cartilage. When chondroblasts are embedded in the cartilage matrix and cease dividing, they become chondrocytes. Chondrocytes are the specialized mature cells found in the cartilage which produces and manages the cartilage matrix. Chondrocytes are composed of collagen fibrils and proteoglycans and responsible for the flexibility of the cartilage. This is the difference between chondroblasts and chondrocytes.
Reference:
1.Lefebvre, Véronique, and Patrick Smits. “Transcriptional control of chondrocyte fate and differentiation.” Birth Defects Research Part C: Embryo Today: Reviews. Wiley Subscription Services, Inc., A Wiley Company, 26 Sept. 2005. Web. 07 Mar. 2017.
2.Zhang, Minjie, Sriniwasan B. Mani, Yao He, Amber M. Hall, Lin Xu, Yefu Li, David Zurakowski, Gregory D. Jay, and Matthew L. Warman. “Induced superficial chondrocyte death reduces catabolic cartilage damage in murine posttraumatic osteoarthritis.” The Journal of Clinical Investigation. American Society for Clinical Investigation, 01 Aug. 2016. Web. 07 Mar. 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. “Elastic cart 100X” By Ganímedes – Own work (CC BY-SA 3.0) via Commons Wikimedia
3. “412 Types of Cartilage-new” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia