This causes it to heal very slowly. The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondrium. There are three types of cartilage: hyaline, fibrous, and elastic cartilage.
Hyaline cartilage is the most widespread type and resembles glass. In the embryo, bone begins as hyaline cartilage and later ossifies. Fibrous cartilage has many collagen fibers and is found in the intervertebral discs and pubic symphysis. Elastic cartilage is springy, yellow, and elastic and is found in the internal support of the external ear and in the epiglottis.
Key Terms chondroitin sulfate : An important structural component of cartilage that provides much of its resistance to compression. Chondrocytes : Cells that form and maintain the cartilage. What is Cartilage?
Types of Cartilage There are three major types of cartilage: hyaline cartilage, fibrocartilage, and elastic cartilage. Hyaline Cartilage Hyaline cartilage is the most widespread cartilage type and, in adults, it forms the articular surfaces of long bones, the rib tips, the rings of the trachea, and parts of the skull.
Fibrocartilage Fibrous cartilage has lots of collagen fibers Type I and Type II , and it tends to grade into dense tendon and ligament tissue. Cartilage: Hyaline cartilage showing chondrocytes and organelles, lacunae and matrix. The extracellular matrix consists of ground substance proteoglycans and glycosaminoglycans and associated fibers, such as collagen. The chondroblasts then trap themselves in lacunae, small spaces that are no longer in contact with the newly created matrix and contain extracellular fluid.
The chondroblast is now a chondrocyte, which is usually inactive but can still secrete and degrade the matrix depending on the conditions. The majority of body cartilage is synthesized from chondroblasts that are largely inactive at later developmental stages compared to earlier years pre-pubescence. The division of cells within cartilage occurs very slowly. Therefore, growth in cartilage is usually not based on an increase in size or mass of the cartilage itself.
Remodeling of cartilage is predominantly affected by changes and rearrangements of the collagen matrix, which responds to tensile and compressive forces experienced by the cartilage.
Cartilage growth thus mainly refers to matrix deposition, but can include both growth and remodeling of the ECM. Early in fetal development, the greater part of the skeleton is cartilaginous.
This temporary cartilage is gradually replaced by bone endochondral ossification , a process that ends at puberty. In contrast, the cartilage in the joints remains permanently unossified during life. Once damaged, cartilage has limited repair capabilities because chondrocytes are bound in lacunae and cannot migrate to damaged areas.
Also, because cartilage does not have a blood supply, the deposition of new matrix is slow. Damaged hyaline cartilage is usually replaced by fibrocartilage scar tissue. Over the last few years, surgeons and scientists have elaborated a series of cartilage repair procedures that help to postpone the need for joint replacement. These include marrow stimulation techniques, including surgeries, stem cell injections, and grafting of cartilage into damaged areas.
However, due to the extremely slow growth of cartilage and its avascular properties, regeneration and growth of cartilage post-injury is still very slow. Privacy Policy. Skip to main content. Skeletal System. Cartilage cushions joints and helps them work smoothly.
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Tenex is a minimally invasive outpatient procedure that uses ultrasonic technology to break up and remove damaged tissue.
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Health Conditions Discover Plan Connect. What Is the Purpose of Cartilage? Medically reviewed by William Morrison, M. Types Damage Treatments Bottom line What is cartilage? What are the different types of cartilage? How can cartilage become damaged? Can cartilage repair itself? The bottom line. Read this next. Costochondritis: Causes, Complications, and Treatment. Look at the eMicroscope of a section of cartilage on the left.
Make sure you can identify chondrocytes , the lacunae, matrix and perichondrium. This image may also be viewed with the Zoomify viewer. This is a section of an invertebral disc , which contains a layer of fibrocartilage. Can you find the fibrocartilage in this section? Identify the chondrocytes in lacunae , and thick bundles of collagen fibres.
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