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Cartilage Structure
Cartilage is a tissue composed of cartilage cells dwelling in a matrix filled with a mix of collagen fibers, elastin, glycoproteins, and sugar compounds. Interestingly, unlike most other tissues in our body, cartilage is deprived of blood and lymphatic vessels. It relies on diffusion from and to surrounding tissues for nutrient supply, immune protection, and waste excretion. The lack of direct blood action is also the reason why joint cartilage takes more time to heal after an injury, and in many cases never heals completely. Cartilage also lacks nerve supply. In contrast to other tissues, injured or damaged cartilage does not trigger pain. Instead, discomfort often stems from the inflammation of neighboring structures, such as joints and bones.
Types of Cartilage in the Human Body
There are three types of cartilage in the human body that differ from each other in composition and corresponding functions. Let's start with hyaline cartilage – the most abundant cartilage type containing type II collagen fibers. Picture it as the smooth-textured operator, mainly located at the nose tip, in your breathing passages, and, of course, on the articular bone surfaces in your joints. The functions of hyaline cartilage in our joints are to minimize friction, provide vital support to handle pressure and ensure effortless movement of joints.
Elastic cartilage, in addition to type II collagen fibers, also contains elastin - a protein that gives this type of cartilage a distinct characteristic. Elastic cartilage is essential for parts of your body that need to bend and move freely. It can be found in the larynx, epiglottis, outer ear, and the tube connecting your middle ear to your throat (the auditory tube).
Last but certainly not least, fibrocartilage contains both type I and type II collagen. This robust cartilage thrives in places subjected to compression and shear forces, providing the structural support and rigidity needed to endure the challenges of high-stress zones.
Cartilage Functions
During embryonic development, cartilage is a foundational precursor to the bone, laying the groundwork for the skeletal structure that will define our physical form. As the embryo progresses, some of this cartilage undergoes a transformation, solidifying into the bone and contributing to the robust framework of our bodies. However, not all cartilage takes on this metamorphic destiny. A significant portion persists, strategically dispersed throughout the body to fulfill their functions.
- Shock absorption. Joint cartilage acts as a cushion for shock absorption during joint movement.
- Friction reduction. Joint cartilage surrounds the articulating surfaces of bones in joints, facilitating smooth movement without friction.
- Attachment. Fibrocartilage aids in attaching tendons and ligaments to the bone, providing strength and stability to these critical connections in the musculoskeletal system.
Structural support. Cartilage provides structural support to diverse body parts, including the nose, ears, and trachea.
