3 Types of Cartilage

Three Types of Cartilage

Cartilage is a connective tissue. The three types of cartilageA flexible connective tissue found in joints, the ear, nose, and rib cage. Cartilage can be of three along with bone are collectively called supportive connective tissues. There are limited places where fibrocartilageA tough, shock-absorbing cartilage found in intervertebral discs and menisci. is located and limited places where elastic cartilageA flexible cartilage type found in the ear and epiglottis. is located. Hyaline cartilage is the most common cartilage in the human body. It exists in so many places that we couldn’t even label it on this picture. For example there is hyaline cartilageThe most abundant cartilage type, found in joints, ribs, and the nose. connecting ribsCurved bones forming the rib cage; articulate with thoracic vertebrae and most with the sternum. to the sternumFlat bone forming the center of the chest; anchor for ribs and clavicles. Appears as a vertical dagg. We also have hyaline cartilage where two bones meet, such as at the shoulder, knee, or elbow.  This type of cartilage is called articular cartilage because it is located at an articulation.  The hyaline cartilage that makes up your nose is called nasalTwo small rectangular bones forming the bridge of the nose. cartilage because of its location.  All these places have the tissue hyaline cartilage. We will give the cartilage formation a more specific name based on its location.

Cartilage is neither innervated nor vascularizedTo invade a tissue with blood capillaries.. This is why we are able to pierce ears noses and other flaps of cartilage. The piercings do not heal and the holes remain open.  I always have students say to me yeah but the holes heal. No, they don’t. The skinThe body’s largest organ, providing protection and regulation. heals over the hole in the cartilage, creating the appearance of healing. The cartilage itself has a permanent hole. It refuses to heal.

Hyaline Cartilage

The prefix HYA comes from a root Latin word that means glassy. This means that between the chondrocytes, the most common cellsThe basic structural and functional units of life. in cartilage, the matrix has a glassy appearance. We understand that the matrix of any connective tissue consists of the ground substance. It also includes the fibers that surround all cells, resembling gelatin with fruits in it. In these two pictures the chondrocytes they kind of look like ovals with an eye on them. Between all of these chondrocytes, the matrix has collagenA structural protein in the dermis that provides strength and elasticity. fibers in it. There are very few fibers present. As a result, the matrix takes on a glassy appearance, as seen in the picture on the right.

Elastic Cartilage

Elastic cartilage is found only in your ear and your epiglottisA flap of cartilage that covers the trachea during swallowing to prevent food from entering the airw. The epiglottis is the flap that covers your trachea when you are swallowing food down your throat to your esophagusThe muscular tube that transports food from the pharynx to the stomach via peristalsis..  Elastic cartilage is essentially just hyaline cartilage with a whole lot of elastic fibers in the matrix. I have represented this by drawing a whole bunch of squiggly lines in the drawing on the left. There seem to be scratches in the matrix between the chondrocytes. These darkly stained scratches are the elastin fibers caught in the matrix making this elastic cartilage.

Fibrocartilage

Fibrocartilage can be found at various articulations. It is especially present where bone directly contacts other bone. Students can usually connect to fibrocartilage being the menisci in the knee. A meniscus is a pad that reduces the shock or the superiorAbove or toward the upper part of the body. inferiorBelow or toward the lower part of the body. forces of gravity. At the knee, there is a lateral meniscusShock absorber Cartilage on outer knee joint; cushions and stabilizes joint.. There is also a medial meniscusShock absorber Cartilage on inner knee joint; cushions and stabilizes joint.. Both mediate the connection of the distal condyles of the femurThigh bone; longest and strongest bone in the body; has a large round head and prominent trochanters and the proximalCloser to the point of attachment or origin. condyles of the tibiaShinbone; large, weight-bearing medial bone of the lower leg..

The other place you may know fibrocartilage from is the discs in your spineProminent ridge on the posterior scapula dividing it into supraspinous and infraspinous fossae.. They are located between the individual vertebra. The picture in the middle here is a top down image. We are looking from above at a transverse cut of the spinal cordThe central nervous system structure that relays signals between the brain and body.. The yellow structure in the center is the spinal cord itself with two nerves coming off the sides. The blue oval is the fibrocartilage disc. It protects the impact between the vertebra below it. It also protects the vertebra above it. People with lower back problems can have various stages of bulging or herniated discs. These discs have an internal blue portion. It forms a bubble due to pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange.. This bubble pushes itself out the posterior side, putting pressure on the spinal cord. Everybody has degenerative disc disease. It’s just a matter of how fast your degeneration is happening. 

Fibrocartilage is very difficult to stain because the collagen fibers and their orientation require a different stain than the chondrocytes. In order to be successful the cytoplasmThe gel-like substance within a cell that contains organelles and cytosol. of each chondrocyteMature cartilage cells housed in lacunae. has to be removed. In the histological picture here, you can see a few chondrocytes by their very darkly stained nucleusThe control center of the cell that contains DNA and directs cellular activities.. Around them, there is nothing stained, just a clear area around the nucleus of each cell.