Most connective tissues have a rich supply of blood, with the exception of cartilage. The delivery of nutrients through blood is extremely essential for quick recovery. Due to the minimal or limited blood supply, cartilage injuries in adults take a much longer time to heal.
These three types differ in terms of their elasticity, structure, tensile strength, etc. While the hyaline cartilage contains type II collagen fibers that are widely dispersed, the elastic cartilage contains many elastic fibers. Fibrocartilage is toughest amongst them and is densely packed with collagen fibers.
➠Just below the thyroid cartilage, as a ring-shaped piece of hyaline cartilage called the cricoid cartilage
➠At places where the ribs attach to the sternum (as costal cartilage)
➠In the trachea (as rings of the trachea, arytenoid cartilage (a pair of pyramidal-shaped cartilage that anchor and help move the true vocal cords), cuneiform cartilage, corniculate cartilage)
➠ In the primary bronchi as cartilage rings
➠In the secondary bronchi as irregular plates of cartilage
➠Between the joints such as knees, hips, shoulder, etc., as articular cartilage
Articular cartilage covers the surface of the ends of bones. It acts as a shock-absorber. For instance, the cartilage in the knees helps transmit the load when we run, bend, stretch, or perform any physical activity. The outer layer of the cartilage is referred to as the gliding zone. One of the main functions of this type of cartilage is to enable the bones in the joints to move and glide over each other without friction. On account of being avascular (lacking blood supply), articular cartilage can get damaged due to the normal wear and tear that occurs with age or an injury. The degeneration of the cartilage in old age gives rise to the degenerative joint condition called osteoarthritis.
It has chondrocytes surrounded with a thin collagenous network of cartilage-extracellular matrix, and the dense networks of elastic fibers are found between these regions. The differentiating factor between the two types of cartilage is the presence of elastin fibers that are embedded in the ground substance. Perichondrium is also found around this type of cartilage. It helps in forming and maintaining the shape of certain structures of the body. It is a supportive, elastic tissue that provides firmness and flexibility. It can be found at the following places:
➠Pinna or the cartilaginous structure in the external ears
➠Pharyngotympanic (Eustachian) tubes
➠Parts of the nose
➠Parts of the larynx
➠Parts of the epiglottis, which is the flap that covers the opening of the larynx during swallowing
➠In the intervertebral discs in the spine
➠Menisci in the knees
➠Pubic symphysis, which is place where the hip bones join at the front of the body
➠Smaller respiratory tubes
➠Articular surfaces of bones in synovial joints
➠Costal cartilages (rib cage)