TYPES OF CARTILAGES AND STRUCTURE OF COMPACT BONE

TYPES OF CARTILAGES :
There are three types of cartilages ; 1) Hyaline Cartilage 2) Elastic cartilage 3) Fibrous cartilage
1) Hyaline Cartilage :
i.It is bluish-white in colour
ii.It is transluscent
iii.Collagen fibre are present
iv.Perichondrium is present except in articular cartilage , epiphysial plates ans costal cartilages
v.This is weakest cartilage
Eg; Articilar cartilages , Costal cartilages ,walls of nose etc
2) Elastic cartilage:
i. Matrix has more elastic fibres than collagen fibres
ii. It is yellowish in colour
iii. Perichondrium is present
Eg; Ear pinna , Eustachian tube and Epiglottis
3) Fibrous cartilage:
i. Its matrix contains dense network of collagen fibres
ii. Perichondrium is absent
iii. Strongest cartilage
Eg; Intervertibral discs , Pubicsymphysis
DETAILED ACCOUNT OF COMPACT BONE :
1. It has dense matrix
2. Diaphysis of long bones is compact bone
3. It is lined by edosteum on the internal surface and lined by periosteum on external surface
4. In the matrix co9llagen fibres are arranged in lamellae
5. Haversian systems are present between outer and inner circumferential lamellae
HAVESIAN SYSTEM:-
6. Each havrsian system consists of haversian canal
7. Haversian canal is surrounded by concentric lamellae
8. Lacunae containing osteocytes found between lamellae
9. Each lacuna encloses ine osteocyte
10. Volkman’s canal connects the two adjacent haversian canals
11. Blood vessels , lymph vessels and nerves enter into havesian canals
12. havesian system is also called “Osteon”
CHEMICAL COMPOSTION :
• Organic Composition - 35%
• Inorganic composition - 65%
• The major organic substance is collagen
• The major mineral is calcium phosphate
• Calcium phosphate is present in the form of hydroxyl apatite crystals - Ca10 (PO4)(OH)2