Histology lecture ..Cartilage tissue.pptx

Histology of cartilage tissue

1. Cartilage

2. Cartilage is a specialized form of connective tissue. it consists of cells (chondrocytes) and extracellular matrix.

3. The chondrocytes are found in matrix cavities called lacunae . They synthesize and secrete the extracellular matrix

4. Functions of cartilage The firm consistency of the extracellular matrix allows the tissue to bear mechanical stresses without permanent distortion. support soft tissues. shock-absorbing and sliding area for joints and facilitates bone movements. Cartilage is also essential for the development and growth of long bones both before and after birth.

5. Cartilage is a vascular and have no lymphatic vessels or nerve endings. Its surrounded by dense connective tissue the perichondrium and it gives the vascular, lymphatic and sensory supply to cartilage . Articular cartilage has no perichondrium and gets the nutrients by diffusion from the synovial fluid.

6. Types According to the functional requirement and the composition of extracellular matrix there are 3 types of cartilage: Hyaline Elastic Fibrocartilage.

7. Hyaline cartilage The most common type. Is found in the articular surfaces of the movable joints, in the walls of larger respiratory passages (nose, larynx, trachea, bronchi), in the ventral ends of ribs, and in the epiphyseal plate, where it is responsible for the longitudinal growth of bone. The matrix contains collagen fibrils type 2 mainly and macromolecules.

8. At the periphery of hyaline cartilage, young chondrocytes have an elliptic shape, with the long axis parallel to the surface. Farther in, they are round and may appear in groups of up to eight cells originating from mitotic divisions of a single chondrocyte. These groups are called isogenous .

9. Growth of cartilage interstitial growth; resulting from the mitotic division of preexisting chondrocytes, it occurs in the epiphyseal plates of long bones and within articular cartilage.

10. appositional growth; Chondroblasts of the perichondrium proliferate and become chondrocytes once they have surrounded themselves with cartilaginous matrix and are incorporated into the existing cartilage

11. Elastic cartilage occurs in the epiglottic cartilage, the corniculate and cuneiform cartilage of the larynx, the cartilage of the external ear and the auditory tube. corresponds histologically to hyaline cartilage, but, in addition, elastic cartilage contains a dense network of delicately branched elastic fibres .

12. Fibrocartilage it’s a transition between dense connective tissue and hyaline cartilage. Chondrocytes may lie singly or in pairs, but most often they form short rows between dense bundles of collagen fibres . collagen fibers type I is dominant in fibrous cartilage.

13. It is found in intervertebral disks, in attachments of certain ligaments to the cartilaginous surface of bones, and in the symphysis pubis.