Structure of Cartilage and Bone | Biology for JAMB PDF Download

Cartilage and bone are essential components of the skeletal system in humans and other vertebrates. They provide support, protection, and enable movement. Understanding their structure is crucial for a comprehensive understanding of the skeletal system. Here are the key points regarding the structure of cartilage and bone:

Cartilage

• Cartilage is a type of connective tissue that is flexible, yet resilient. It is found in various parts of the body, including the joints, ears, nose, and respiratory passages.
• The cells in cartilage are called chondrocytes, which are embedded in a gel-like matrix called the extracellular matrix.
• The extracellular matrix of cartilage is composed of collagen fibers, elastic fibers, and a gel-like substance called ground substance. This composition gives cartilage its strength and elasticity.
• Cartilage lacks blood vessels and nerves, which makes it a slow-healing tissue.

Types of Cartilage

• Hyaline Cartilage: This is the most common type of cartilage in the body. It provides support and reduces friction between bones in joints. It is found in the rib cage, nose, trachea, and ends of long bones.
• Elastic Cartilage: This type of cartilage contains more elastic fibers, making it more flexible. It is found in the external ear and the epiglottis.
• Fibrocartilage: Fibrocartilage is the toughest type of cartilage due to its dense arrangement of collagen fibers. It is found in intervertebral discs, knee menisci, and the pubic symphysis.

Bone

• Bones are rigid organs composed of living cells, collagen fibers, and a hard mineralized matrix, mainly consisting of calcium and phosphate.
• The basic structural unit of compact bone is called an osteon or Haversian system. It consists of concentric layers of bone tissue called lamellae surrounding a central canal, which contains blood vessels and nerves.
• The spongy or cancellous bone is composed of trabeculae, which are interconnecting plates and struts that provide strength and support.
• Osteocytes are the mature bone cells that are located in small spaces called lacunae within the bone matrix. They maintain the bone tissue and help with nutrient exchange.
• Blood vessels and nerves permeate bones, providing oxygen, nutrients, and innervation.

Bone Marrow

• Bone marrow is a soft, gelatinous tissue found in the central cavities of certain bones, such as the femur and sternum.
• Red bone marrow is responsible for the production of blood cells, including red blood cells, white blood cells, and platelets.
• Yellow bone marrow consists mainly of fat cells and serves as an energy reserve.

Understanding the structure of cartilage and bone is essential for comprehending their functions and the overall functioning of the skeletal system. It provides the foundation for learning about bone growth, repair, and the various skeletal disorders that can arise.

Conclusion

In conclusion, the structure of cartilage and bone plays a vital role in maintaining the integrity and functionality of the skeletal system. Cartilage, with its flexible and resilient nature, provides support and protection in various parts of the body. Its extracellular matrix composition gives it strength and elasticity. On the other hand, bones, with their complex structure of living cells, collagen fibers, and mineralized matrix, provide rigidity and support for the body while allowing for movement. The understanding of cartilage and bone structure is fundamental in comprehending bone growth, repair, and the prevention and treatment of skeletal disorders.