Osteology

in the shaft of long bone

where is bone marrow found?

stem cells that CREATE osteoblast and clast

what are osteogenic cells?

a matrix of calcium salts and collogen

what is bone made up of?

45% calcium and phosphates

30% fibrous tissue

25% water

what are the composition of bone?

what is the matrix

osteocytes

what forms the matrix

Made up of osteons or Haversian systems

In the Haversian canals are blood vessels which the innermost osteocytes connect with to receive nutrients and oxygen, these products are then passed to the osteocytes in the outer rings .

what is the compact/cortical bone made up of?

meshwork of spicules

forms the medullary cavity

what is cancellous bones made up of

where is red marrow found in adults?

when it runs out of cartilaginous building blocks

why does fusion of growth plate occur?

originate between layers of connective tissues

Intramembranous bones…?

begin as cartilaginous masses that get replaced by bone tissue

Endochondral bones…?

It takes place in the membrane in developing foetus (skull vault & facial bones)

Fibroblasts become osteoblasts and start to produce a bone matrix.

Calcium salts are deposited to form Osteiod tissue (calcification)

Ossification spreads from centre outwards

describe the process of intramembranous ossification

The rest of the skeleton is formed of cartilage and ossification starts in the 3^rd month of gestation

Osteoblasts produce a bone matrix in the diaphysis of long bones, centre of short, flat and irregular bones.

The bone matrix slowly replaces the original cartilage.

In long bones centres of ossification also form at the epiphysis

describe the process of Endochondral Ossification

In embryonic long bones they reabsorb the bone matrix to form the medullary cavity

Allows blood vessels to grow and red marrow is formed

How are osteoclasts involved in endochondral ossification?

The epiphyseal plate is laying down cartilage, and on the diaphyseal side osteoblasts continue to change this matrix to a bony matrix.

What happens at epiphysis

Factors affecting ossification? - Genetics

Nutrients

stimulate effects in certain cells for ossification

Hormones

Without stress of exercise on bones they lose Ca+ faster than is replaced

Exercise