Bone composition Flashcards
(25 cards)
What is the bone matrix made up of/percentages?
Water - 25%
Organic protein fibres (mainly collagen 1) - 25%
Crystallised mineral salts - 50%
Name the 2 different types of bone tissue
Compact bone and spongy bone
What is spongy bone arranged in
Trabeculae
What is found in spaces between trabeculae?
Bone marrow
Where in the bone is spongy bone found?
In the middle
Where in the bone do you find compact bone
On the outer layer
What is compact bone organised into?
Osteons
What is found at the centre of each osteon?
A canal forming layers called lamellae
What are the spaces between lamella layers called@?
Lacunae
Where are osteocytes found?
Lacunae
Name the 5 types of bones
Long, flat, short, sesamoid, irregular
Name the 4 cells found in bones
Osteocytes, osteoblasts, osteoclast and osteoprojenitor cells
What do osteoprojenitor cells differentiate to
Osteoblasts
Where are osteoprojenitor cells found
Periostium and endiostium
What do osteoblats do
Build up bone
How do osteoblasts produce bone matrix
Osteoblasts produce bone matrix by synthesising/secreting collagen fibres and other organic components. This dephosphorylates molecules initiating the calcification of bone matrix by depositing calcium phosphate.
How is an osteoid formed
One bone matrix is calcified, molecules react with eachother to form rigid but flexible bone tissue called osteoid
What do osteoblasts differentiate into
osteoclasts
Where do osteoblasts form in a cell
On the outer layer of a cell
Where are osteocytes found?
Osteocytes are found entrapped in their own matrix in mature bone
What is the function of osteocytes?
To maintain the cellular activities of bone
Are osteoclasts multinucleated?
Yes
Do osteocytes secrete matrix?
No
Describe the membrane of an osteoclast
Face bone and releases lyosomal matrix and enzymes that digest bone/protein material
