Composition Function And Classification Of Bone

Bone is a special type of highly vascular, mineralized and constantly changing rigid connective tissue which forms the framework of body.













Composition Of Bone


Bone is composed of 
  1 Cell 
i)   Osteocyte
ii)  Osteoblast
iii) Osteoclast

2 Intercellular matrix

i) Water
ii) Organic  
           (a) Collagen fiber
           (b) Glycosaminoglycan-
                     i) Chondroitin sulphate
                     ii) Keratan sulphate

iii) Inorganic
             (a) Calcium phosphate
             (b) Calcium carbonate
             (c) Magnesium phosphate
             (d) Others -Na, K, I, Fe, CI



Function Of Bones

Give shape to the body

Give support to the body

Provide surface for the attachment of muscles,tendons and ligaments.

Produce blood cells.

Mechanical protection of vital organs such as brain ,heart,lung.

Storage of body calcium & phosphorus.



Classification Of Bone

Microscopically 
             1 Compact or dense-e.g. shaft of long bone.
              2 Spongy or cancellous bone -ends of long bone.

According to position
              1 Axial : Bone forming the axis of the body e.g. skull                    rib etc.
               2 Appendicular :Bone forming the skeletal of limbs.
                   e.g. radius,femur etc.

According to size and shape

Long bone 

                Typical: they have two epiphysis. examples-
                 Humerus,radius ulna,femur etc.

                Miniature : they have only one epiphysis. e.g.                          metacarpal ,metatarsal & phalanges.

                 Modified : they have no medullary cavity .e.g.                          clavicle ,body of vertebra.



Short  bone - e.g. carpal & tarsal

Flat bone -   e.g scapula,sternum,ribs,parietal & frontal                               bones.

Irregular bone - e.g. vertebra,hipbone and base of skull.

Pneumatic bone -e.g. maxilla,sphenoid,Ethmoid etc.

Sesamoid bone - e.g. patella, pisiform.