Main Difference – Fibrocartilage vs Hyaline Cartilage

Fibrocartilage, hyaline cartilage, and elastic cartilage are the three types of cartilage that are found in the human body. Cartilages are a type of connective tissue that is made up of chondrocytes and an extracellular matrix.  In the fetus, the skeleton is completely made up of cartilage. Then the cartilages are replaced with bones. The fibrocartilage is found in the pubic symphysis, menisci of the stifle joint, and the annulus fibrosis of the intervertebral discs. It serves as a transitional cartilage. The hyaline cartilage is found in the nasal septum, trachea, ends of the growing bones, and in between the ribs and the sternum. The main difference between fibrocartilage and hyaline cartilage is that fibrocartilage is stiff and contains many collagen fibers whereas hyaline cartilage is a soft cartilage that contains fewer fibers.

Key Areas Covered

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

Key Terms: Bones, Chondrocytes, Chondroitin, Collagen Fibers, Fibrocartilage, Glycosaminoglycan (GAG), Hyaline Cartilage, Joints

What is a Fibrocartilage

Fibrocartilage refers to a cartilage that contains numerous collagen fibers in the extracellular matrix. Collagen type I and type II occur in the fibrocartilage. The fibrocartilage provides flexibility, toughness, and elasticity to the structural parts of the body. It contains intermediate characteristics between the dense connective tissue and the hyaline cartilage. The types of cells that occur in the fibrocartilage are fibroblasts, fibrocytes, chondroblasts, and chondrocytes. The chondrocytes occur in the lacunae. Fibroblasts lack a perichondrium. The ground substance of the fibrocartilage contains equal amounts of dermatan sulfate and chondroitin sulfate. The fibrocartilage is shown in figure 1.

Figure 1: Fibrocartilage

The fibrocartilage occurs in the pubic symphysis, menisci of the stifle joint, and the annulus fibrosis of the intervertebral discs. The fibrocartilage is often associated with the dense connective tissue and its main function is to attach bones to other bones and provide restricted mobility in the joints.

What is a Hyaline Cartilage

Hyaline cartilage refers to a translucent, bluish-white color cartilage that mainly occurs in joints. In the fetus, the skeleton is first laid down as the hyaline cartilage. In the adolescence, the calcification of the hyaline cartilage is replaced by the bones. However, the most abundant type of cartilage in adults is the hyaline cartilage. The hyaline cartilage occurs in the articular surface of the long bones, the tips of the ribs, and the rings of the trachea. The hyaline cartilage is covered by a fibrous membrane called perichondrium. The hyaline cartilage is shown in figure 2.

Figure 2: Hyaline Cartilage

The hyaline cartilage contains a less number of collagen fibers. Therefore, the cartilage is somewhat flexible and tough. The matrix of the hyaline cartilage contains collagen fibrils of type II collagen and glycosaminoglycans (GAGs). Since the GAGs trap a lot of water, the hyaline cartilage consists of a high diffusion rate. The hydrated nature of the hyaline cartilage allows shock absorbance. The main function of the hyaline cartilage is to provide smooth and lubricated surfaces for the movements of the bones at joints. 

Similarities Between Fibrocartilage and Hyaline Cartilage

• Fibrocartilage and hyaline cartilage are two types of connective tissues.
• Both fibrocartilage and hyaline cartilage are made up of chondrocytes and the extracellular matrix, which is secreted by the chondrocytes.
• The extracellular matrix of the fibrocartilage and hyaline cartilage contain collagen fibers.
• Both fibrocartilage and hyaline cartilage lack blood vessels, lymphatic vessels, and nerves.
• Both fibrocartilage and hyaline cartilage provide a smooth and lubricated surfaces for the movement of bones.
• The flexibility of both fibrocartilage and hyaline cartilage is due to chondroitin.

Difference Between Fibrocartilage and Hyaline Cartilage

Definition

Fibrocartilage: Fibrocartilage is a cartilage that is made up of thick, compact, parallel collagen bundles and chondrocytes.

Hyaline Cartilage: Hyaline cartilage is a translucent, bluish-white color cartilage that occurs in the respiratory tract, joints, and the immature skeleton.

Amount of Fibers

Fibrocartilage: Fibrocartilage contains a higher number of collagen fibers.

Hyaline Cartilage: Hyaline cartilage contains a fewer number of collagen fibers.

Type of Collagen

Fibrocartilage: Fibrocartilage contains both type I and type II collagen fibers.

Hyaline Cartilage: Hyaline cartilage contains only the type II collagen fibrils.

Chondrocytes

Fibrocartilage: Fibrocartilage contains a few chondrocytes in lacunae.

Hyaline Cartilage: Hyaline cartilage contains large chondrocytes in lacunae.

Appearance

Fibrocartilage: Fibrocartilage is a glass-like, translucent, bluish-white color cartilage.

Hyaline Cartilage: Hyaline cartilage is white in color.

Perichondrium

Fibrocartilage: Fibrocartilage lacks a perichondrium.

Hyaline Cartilage: Hyaline cartilage contains a perichondrium (except the hyaline cartilage at the end of the growing bones).

Location

Fibrocartilage: The fibrocartilage occurs in the pubic symphysis, menisci of the stifle joint, and the annulus fibrosis of the intervertebral discs.

Hyaline Cartilage: The hyaline cartilage occurs in the nasal septum, trachea, ends of the growing bones, and in between the ribs and the sternum.

Function

Fibrocartilage: Fibrocartilage attaches bones to other bones and provides restricted mobility to the joints.

Hyaline Cartilage: Hyaline cartilage facilitates the smooth and lubricated movements of the bones at joints.

Conclusion

Fibrocartilage and hyaline cartilage are two types of cartilage that occur in animals. Fibrocartilage contains a lot of collagen fibers in the matrix. But, hyaline cartilage contains fewer collagen fibers in the matrix. Both fibrocartilage and hyaline cartilage provide smooth and lubricated surfaces between bones. They also absorb shocks. The main difference between fibrocartilage and hyaline cartilage is the density of collagen fibers in each type of cartilage.

Reference:

1. “Cartilage System.” Fibrocartilage, Available here. Accessed 11 Sept. 2017.
2. “Hyaline cartilage.” VPh 308 – Histology, Available here. Accessed 11 Sept. 2017.

Image Courtesy:

1. “Fibrocartilage” by Brittany (CC BY 2.0) via Flickr
2. “Hyaline cartilage” by Brittany (CC BY 2.0) via Flickr

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