1. Cartilage
Dr.PARDEEP KUMAR

2. CARTILAGE
 It is a specialized form of connective tissue consists of cells, fibres & ground substance. The cells are embedded in the intercellular matrix
 Origin - Mesenchymal in origin.

3. Cartilage Embryo More prevalent than in adult
Skeleton initially mostly cartilage
Bone replaces cartilage in fetal and childhood periods

4. Location of cartilage in adults
External ear
Nose
“Articular” – covering the ends of most bones and movable joints
“Costal” – connecting ribs to sternum
Larynx - voice box

5. Epiglottis – flap keeping food out of lungs
Cartilaginous rings holding open the air tubes of the respiratory system (trachea and bronchi)
Intervertebral discs
Pubic symphysis
Articular discs such as meniscus in knee joint

6. Composition:
1) Cells: Chondrocytes, Chondroblasts
2) Fibres: White fibers and yellow elastic fibres.
3) Ground substance: Consists of Glyco-samino-glycans:
i) Chondroitin sulfate.
ii) Kerato sulfate.
iii) Hyaluronic acid.

7. Characteristics of cartilage
Avascular, devoid of lymphatics & nerves. Gets its nutrition from blood vessels of adjacent tissue by process of diffusion
Its matrix is not calcified ( Cartilage turn into bone by calcification)
Cartilage grows by 2 methods
Interstitial (endogenous method)
Appositional (exogenous growth)
It forms skeleton of body in early life, most of which is replaced by bone in adult

8. Growth of a cartilage
Cartilage grows by 2 methods
Interstitial growth : Expansion of internal mass of cartilage by division of chondrocyte ("in the middle“)
Increasing in LENGTH; chondrocytes divide and secrete matrix from w/in lacunae
Appositional growth : when cartilage grows by adding new layer on its surface by the cells of perichondium ("at the edge“)
Increasing in WIDTH; chondroblasts deposit matrix on surface of pre-existing cartilage

9. Functions of Cartilage
Supports soft tissues of body
Facilitates bone movement by virtue of its smooth surface 
Nutrition of Cartilage
Cartilage is avascular
Hyaline & elastic cartilage gets nutrition from vessels of Perichondrium
Fibro cartilage gets nutrition from blood vessels of surrounding connective tissue & articular cartilage from synovial fluid

10. Perichondrium ( covering of cartilage)
Dense fibrous connective tissue which encloses cartilage is called Perichondrium
It is essential for the growth & maintenance of cartilage

11.  CHONDROCYTES & CHONDROBLASTS
They are cartilage cells, irregular in shape.
The almond shaped spaces they occupy are lacunae.
They may remain in ground substance widely separated as discrete or in groups.
They are developed from mesenchymal cells.

12. Types of cartilage: 3 Hyaline cartilage: flexible and resilient
Chondrocytes appear spherical
Lacuna – cavity in matrix holding chondrocyte
Collagen the only fiber
Elastic cartilage: highly bendable
Matrix with elastic as well as collagen fibers
Epiglottis, larynx and outer ear
Fibrocartilage: resists compression and tension
Rows of thick collagen fibers alternating with rows of chondrocytes (in matrix)
Knee menisci and annunulus fibrosis of intervertebral discs

13. FUNCTION Types: Three types of CARTILAGE (1) Hyaline cartilage:
It is translucent so called hyaline
Fibres are scanty, relatively cellular i,e more Chondrocytes with more ground substance.
FUNCTION
Support tissue and organs

14. Examples of Hyaline Cartilage:
Articular cartilage
Costal cartilage
Trachea, bronchi,
Nasal cartilage etc

15. Hyaline Cartilage

16. FUNCTION Support with great tensile strength
(2) White fibro-cartilage:
It contains dense white fibrous tissue Chondrocytes in more collagen fibre, few ground substance.
FUNCTION
Support with great tensile strength

17. (2) White fibro-cartilage:
Examples:
Inter vertebral disc,
Glenoid & Acetabular Labrum
Pubic symphysis etc

18. Fibrocartilage

19. Intervertebral Discs
It is a fibrocartilaginous disc, situated between the bodies of 2 vertebrae & held to them by means of ligament.

20. It has 2 component
Annulus fibrous / outer cartilaginous
It has external layer of dense connective tissue, but is mainly composed of overlapping lamina of cartilage
Nucleus pulposus/ Inner liquid
It is situated in the centre of annulus fibrosus. It consists of few rounded cells embedded in amorphous fluid rich in hyaluronic acid

21. Functions
They allow certain amount of movement between vertebrae
They act as shock absorber
They prevent friction between corresponding vertebrae
They contribute about 1/5th of total length of the vertebral column

22. FUNCTION (3) Yellow elastic cartilage:
It is a modified elastic connective tissue in which elastic fibers are numerous
More yellow elastic fibres, Chondrocytes in scanty ground substance.
Examples:
External ear,
Epiglottis,
Auditory tube,
Some laryngeal cartilage
FUNCTION
Support with flexibility

23. Elastic Cartilage

24. Traits
Hyaline
Fibrocartilage
Elastic
Appearnce
Bluish white
Dense white
Yellow
Translucensy
Tarnslucent
Opaque
Source
Modified areolar CT
Mod. Collagenous CT
Mod elastic CT

25. Traits
Hyaline
Fibro cartilage
Elastic
Composition
Numerous cartilage cells & very fine collagenous fibers.
Numerous coarse, wavy collagenous fibers arranged in bundles with fibroblast & some chondrocytes between
Numerous elastic fibers. Few cartilage cells & collagenous fibers are also present
Calcification
Occurs frequently
Does not occur
Occurs very raely, if any