Cartilage
Cartilage has a rubber-like extracellular matrix that is produced by chondrocytes that sit in lacunae (pockets) which give the cells of cartilage a unique look that can sometimes be easy to identify. However, you will need to be able to recognize the specific cartilage type.
Hyaline cartilage
Hyaline cartilage provides structure to our organs, like bone does, but has more flexibility and resiliency (bend without breaking) than bone does. Hyaline cartilage is found on the tip of our nose, around the tubes of our respiratory system, joining our ribs to our sternum (costal cartilage), and at the ends of our long bones to cushion our joints (articular cartilage). Hyaline cartilage has a chondrocytes in lacunae and the matrix between chondrocytes has special, soluble collagen fibers that give it a smooth, glassy appearance.
Table 1: Hyaline cartilage
| Tissue Type | Hyaline Cartilage |
|---|---|
| General Description | Chondrocytes in lacunae separated by smooth, glassy extracellular matrix |
| Locations | Trachea, nose, larynx, end of long bones, and cartilage that holds ribs to sternum |
| Functions | Strong yet flexible, it provide support to joints and other body structures |
| Helpful Hints | Look for the smooth extracellular matrix between the chondrocytes, looks like a stained glass window |
Figure 1: Hyaline cartilage with and without illustration overlay
Check out our YouTube video to help you understand hyaline cartilage:
YouTube Video – Hyaline Cartilage
Elastic cartilage
Elastic cartilage provides structure with lots of flexibility and is located in the ears and epiglottis. In addition to the collagen matrix seen in hyaline cartilage, elastic cartilage also has many darkly-staining elastic fibers in the extracellular matrix between the chondrocytes (in lacunae).
Table 2: Elastic cartilage
| Tissue Types | Elastic Cartilage |
|---|---|
| General Description | Chondrocytes in lacunae separated by extracellular matrix with abundant elastic fibers |
| Locations | Ears and epiglottis |
| Functions | Supports body structures that need more bend to function |
| Helpful Hints | Look for the elastic fibers in the extracellular matrix between the chondrocytes |
Figure 2: Elastic cartilage with and without illustration overlay
Check out our YouTube video to help you understand elastic cartilage:
YouTube Video – Elastic Cartilage
Fibrocartilage
Fibrocartilage provides flexibility and strength against compression because it contains the form of collagen found in our tendons and ligaments. Fibrocartilage is located in the pubic symphysis (joint at the front of the pelvis), intervertebral discs (between vertebrae), and meniscus of the knee. Fibrocartilage looks like a combination of hyaline cartilage and dense regular connective tissue as you will see many wavy collagen fibers in the extracellular matrix between the chondrocytes.
Table 3: Fibrocartilage
| Tissue Type | Fibrocartilage |
|---|---|
| General Description | Chondrocytes in lacunae separated by extracellular matrix with visible collagen fibers |
| Locations | Pubic symphysis, meniscus of the knee, and intervertebral disc between vertebra |
| Functions | Strongest of the cartilages, resists compression forces of certain joints |
| Helpful Hints | Look for the collagen fibers in the extracellular matrix between the chondrocytes, chondrocytes are often found in rows |
Figure 3: Fibrocartilage with and without illustration overlay
Check out our YouTube video to help you understand fibrocartilage:
YouTube Video – Fibrocartilage
Chapter Illustrations By:
Soma Mukhopadhyay, Ph.D.
mature cells found in cartilage that monitor and maintain the cartilage extracellular matrix
A gap, cavity, or depression. Osteocytes (bone) and chondrocytes (cartilage) are found within lacunae.
cartilage that surrounds the articular surface of bones (surfaces where bone meets bone to form a joint). This cartilage decreases friction in movement and provides cushioning
located in the larynx (throat), moves to prevent food from entering the trachea (airway) during swallowing
provide elasticity to tissues - the ability to be pulled and recoil like a rubber band
