Cartilage has several functions including supporting soft tissues, absorbing shock, and allowing for smooth sliding between surfaces. It is composed of chondrocytes embedded in an extracellular matrix containing collagen, proteoglycans, and other macromolecules. There are three main types of cartilage - hyaline cartilage found at bone ends and in structures like the nose, elastic cartilage in the ear and larynx able to deform and return to shape, and fibrocartilage which forms joints and intervertebral discs composed of collagen fibers and rows of chondrocytes. Cartilage growth occurs through the proliferation and activity of chondrocytes in the growth plate and perichondrium.

1. Cartilage

2. Functions of Cartilage Tissue
1. Specialized CT in which the firm
consistency of the extracellular matrix
allows the tissue to bear mechanical
stresses without permanent distortion
2. Supports soft tissues.
3. Shock-absorbing because it is resilient.
4. Smooth surface allows sliding against it.
5. Essential for growth, development of
bone.

3. Characteristics
1. Chondrocytes (-blasts)
1. Located in lacunae
2. Extensive extra-cellular matrix
1. Fibers, ground substance
2. Collagen, hyaluronic acid, proteoglycans,
glycoproteins, elastic (in elastic cartilage)
3. Macromolecules, water, fibers bind together
and give firm, flexible properties to tissue.
3. No blood, nerve supply
4. Low metabolic rate.

4. Perichondrium
1. Dense CT that
covers cartilage
(except articular
cartilage of joints.)
2. Contains blood,
nerve supply,
lymphatics.
3. Contains collagen
fibers, fibroblasts
Hyaline cartilage

5. Transition Perichondrium / Cartilage

6. Hyaline Cartilage

7. Chondrocytes in Lacunae

8. CARTILAGE (hyaline)
Found at ends of
bones,
nose, trachea, larynx
Bluish white color.
Strong, rubbery,
flexible tissue.

9. Hyaline Cartilage

10. Influence of hormones
1. GH, TH, testosterone accelerates synthesis of
glycosaminoglycans.
2. Cortisone, estradiol inhibits synthesis.
3. Growth depends mainly on GH (somatotroopin)
1. Stimulates liver to produce somatomedin C
2. Somatomedin C acts on cartilage cell, stimulating
growth

11. Growth of Cartilage
• Growth is attributable to two processes:
1. Interstitial growth
1. Mitotic division of preexisting chondrocytes
2. Synthesis of matrix
3. Expands cartilage matrix from within
4. Occurs in epiphyseal plates, articular cartilage
2. Appositional growth
1. Differentiation of perichondria cells → chondroblasts
2. Synthesis of matrix
3. Increase in girth

12. Growth in the Epiphyseal Plate

13. Epiphyseal Plate
(Interstitial Growth)
http://web.indstate.edu/thcme/mwking/glycans.html

14. Appositional Growth

15. ELASTIC CARTILAGE

16. ELASTIC CARTILAGE
1. Similar to hyaline cartilage but has elastic
fibers running in all directions in addition
to collagen.
2. Found in auricle of ear, walls of external
auditory canals, eustachian tubes,
epiglottis, larynx
3. Maintains shape, deforms but returns to
shape; flexibility of organ; strengths and
supports structures.
Ear

17. Elastic Cartilage
Elastic fibers (elastin)
Yellow color

18. Elastic Cartilage
(Epiglottis)

19. Fibrocartilage
• Fibrous Cartilage
• is a form of connective tissue transitional 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. In
contrast to other cartilage types, collagen type I is
dominant in fibrous cartilage.
• is typically found in relation to joints (forming intra-
articular lips, disks and menisci) and is the main
component of the intervertebral disks, symphysis pubis.
• merges imperceptibly into the neighbouring tissues,
typically tendons or articular hyaline cartilage. It is
difficult to define the perichondrium because of the
fibrous appearance of the cartilage and the gradual
transition to surrounding tissue types.

20. Fibrocartilage
Note the rows of chondrocytes
separated by collagen fibers.
Fibrocartilage is frequently found
in the insertion of tendons on the
epiphyseal hyaline cartilage.
Picrosirius-hematoxylin stain.
Medium magnification.

21. FIBROCARTILAGE
Intervertebral disks

22. Fibrocartilage