CARTILAGE

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        CARTILAGE   
  The cartilage is a special type of connective tissue which is characterized by its resilient and pliant nature. It is found at those places in the body where structural support with flexibility is required.

Like all connective tissues, the cartilage is also composed of cells and a large amount of extracellular matrix (ECM). The resilient nature of the cartilage is due to its specialized ECM which is firm but rubbery and pliable. The cells of the cartilage, known as chondrocytes. occupy small spaces within the ECM which are called lacunae. The ECM of the cartilage is secreted by the chondrocytes and consists of ground substance and connective tissue fibers.

 HYALINE CARTILAGE:
       
Hyaline cartilage is the most COMMONLY occurring cartilage in the human body. When examined by the naked eye in the fresh state this variety of cartilage gives a PEARLY _WHITE, TRANSLUCENT, glassy appearance (hence the name HYALINE, Example, glass-like).

Hyline Cartilage
 The hyaline cartilage provides firm but resilient support in different parts and organs of the body. Due to its smooth and pliable surface, It also serves to reduce friction between articulating bony surfaces in movable joints. All hyaline cartilages are covered by a perichondrial covering, except the articular cartilages.

Hayline Cartilage

Found in:
  • Articular cartilage-
  • Costal cartilages (sternum~ribs)
  • Nose
  • Larynx
  • Trachea
  • Bronchi
  • Epiphyseals (b/w bone ends)


FIBROCARTILAGE :

 The fibrocartilage is a tough and strong but resilien tissue. Like other types of cartilage it also consists chondrocytes and ECM. The ECM of the fibrocartilage contains a very high number of type I collagen fibers.


Fibrocartilage
 The fibrocartilage is found in those places in the body where resistance against compression and shearing forces is required. The chief locations of the fibrocartilage are as under:

Found In :
1. Intervertebral discs.
2. Disc of the pubic symphysis.
3. Intra-articular discs of the sternoclavicular and temporomandibular joints.
4. Menisci of the knee joint.
5. Labrum glenoidale (of the shoulder joint) and labrum acetabulare (of the hip joint).

ELASTIC CARTILAGE:

The elastic cartilage is named after its mechanical property of flexibility and elasticity. This variety of cartilage tolerates distortion without damage and returns to its original shape after being temporarily deformed. Like the other varieties of cartilage, the clastic cartilage also consists of chondrocytes and extracellular matrix. The chondrocytes lie within lacunae and occur either singly or in isogenous groups of 2-4 cells. The distinguishing feature of the elastic cartilage is the presence of a dense network of branching and anastomosing elastic fibers.

Elastic Cartilage

 The elastic cartilage has a limited distribution and is found in the following two major locations in the human body:

Found In :
 (1) auricle of the external ear
 (2) epiglottis of the larynx.  
 (3) The elastic cartilage is found in the wall of the external auditory meatus and auditory tube. The small cartilages of the larynx are also made up of elastic cartilage.

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