Cartilage is a connective tissue that provides support and flexibility to various regions of the body. There are three main types of cartilage - hyaline, elastic, and fibrocartilage. Hyaline cartilage is the most abundant and is characterized by chondrocytes embedded in a matrix with collagen fibers and proteoglycans. It is found in locations like the fetal skeleton, nose, and joints. Elastic cartilage contains elastic fibers that allow for flexibility and is present in the ear and epiglottis. Fibrocartilage consists of thick collagen fibers and is found in joints like the pubic symphysis where it can withstand compressive forces.

1. HISTOLOGY OF THE CARTILAGE
DR. DEVI

2. Definition
• Cartilage is a specialized type of dense
connective tissue designed to give support,
bear weight and withstand tension, torsion
and bending.
• Firm ground substance

3. General Features
• Cartilage support regions of the body that
require flexibility
• Not supplied by blood vessels
• Non nervous structure
• Poor regeneration capacity(fibrous tissue)
• Consists of all three components of a CT
• Usually surrounded by perichondrium (except
articular cartilage and fibro cartilage)

4. • Fetal skeleton
• Ends of long bones
• Ossification
• Cartilage canals
• Growth of cartilage-
interstitial growth/appositional growth

5. COMPONENTS
 Cells - chondroblasts and chondrocytes
 Fibers - collagen and elastic
 Ground substance-
mucopolysaccharides (chondroitin
sulphate, Keratan sulphate and
hyaluronic acid)

6. PERICHONDRIUM
•Cartilage is covered externally by a dense
connective tissue sheath known as
perichondrium except articular cartilage and
fibro cartilage.
•Has two layers- outer fibrous layer (vascular)
and inner chondrogenic layer (cellular)
•Has cells which can regrow cartilage to some
extent if the cartilage is damaged.

7. CELLS
• They are derived from undifferentiated
mesenchymal cells
• Young cells are small with branched cytoplasmic
processes known as chondroblasts, they multiply to
chondrocytes
• Older and mature cells are known as chondrocytes

8. • Chondrocytes are bigger in size and are found in
spaces called as lacunae
• They are found either groups of 2-4 cells
together known as cell nest or individual cells
• They are responsible forproduction of fibres
and ground substance of the cartilage
• Old mature cells are incapable of multiplication

9. TYPES
• HYALINE CARTILAGE
• ELASTIC CARTILAGE
• FIBRO CARTILAGE
Differ from each other because of the type
and amount of fibers present in them

10. HYALINE CARTILAGE
• Hyalos=glass
• Most abundant
• Perichondrium present.
• Characterized by the presence of highly
basophilic homogeneous , transparent,
amorphous intercellular matrix
• Appear homogeneous as the collagen fibers
present in them have the same refractive index
as ground substance

11. Cells
• Chondrocyte
• Occupy in lacunae
• Cells are shrunken in H& E
preparation - gaps btw the cells
and lacunae
• responsible for the synthesis of
collagen fibers and ground
substances
• Daughter cells – cell nests

12. Fibers
• Ground substance – type II collagen fibers
• Thick fibers have cross-striations
• Thin fibers- form three dimensional network
• Collagen- stability & strength
• Fibers constitute about the 40% of dry weightof
cartilage

13. • Sulfated proteoglycans (firmness)
• Core protein- glycosaminoglycan
• Chondroitin & keratin sulfate (Acidic)
• Proteoglycans joined to form long hyaluronic
acid
• Hyaluronate proteoglycan aggregates
• Bound to the thin collagen fibers present in
the matrix
Ground substance

14. •Highest concentration present
around the lacuna
• Matrix around the cells is
brighter and deep blue in color
than other areas, this matrix is
known as capsule / territorial
matrix. (newly formed)
• Two groups of cells are
separated by a lightly colored
matrix known inter-territorial
matrix

15. Hyaline cartilage- magnified
Territorial matrix
Interterritorial matrix
Chondrocytes in
lacuna
Cell nest

16. Perichondrium
• Fibrovascular membrane
• Absent in articular surface & costal
cartilage
• Two layers –
i) outer fibrous layer(dense irregular
fibrous connective tissue )
ii) inner cellular layer

17. EXAMPLES• Fetal skeleton
• nose
• Costal cartilages
• Articular cartilages (devoid of
perichondrium)
• Trachea, bronchi, larynx

18. Functions of hyaline cartilage
• Articular cartilage provides smooth surface for
movement at joints
• Though it is flexible, it provides support
because of its firmness
• Firmness of the cartilage keeps the lumen of
trachea and bronchi patent

21. ELASTIC CARTILAGE
• Yellow fibrocartilage
• Perichondrium present
• Characterized by the presence of elastic fibers
in abundance which branch and anastomose
• Chondrocytes are larger than those of hyaline
cartilage
• Chondrocytes are found singly or group two
in lacuna.

24. • Though the matrix of hyaline cartilage calcifies
in old age, the matrix of elastic cartilage
doesn't calcify with age
Function :
• It provides shape and support to the organ
with elasticity

25. EXAMPLES• Auricle or pinna
• Epiglottis
• Tip of arten oids
• Corniculate & cuneiform
cartilage of larynx
• External auditory meatus

26. White Fibrocartilage
• Perichondrium is characteristically absent
• Has thick bundles of collagen fibers (type I)
• Dense regular connective tissue
• Minimal amount of ground substance, few
cells
• Chondrocytes are seen between fibers in
single or in narrow rows

27. • Function :
• Fibrocartilage is capable of resisting
compressive and shear forces

29. EXAMPLES
• Pubic Symphysis
• Manubriosternal
joint
• Intervertebral discs
• Glenoidal labrum of
shoulder joint
• Acetabular labrum of
hip joint, etc.