What type of fibers or minerals do you find in the extracellular matrix of bone? How does this composition relate to the properties of bone?

1 Answer
Apr 2, 2016

Acellular bone is ~30% collagen protein, like cement, and ~70% calcium salts, which act like bricks.


Bone is made of a number of things, largely proteins and calcium-containing minerals, so that they are rigid and do not break easily, providing firm support for the body.

Collagen is the most common protein in the human body and is found frequently in extracellular bone tissue, making up about 30% of the bone. Collagen fibre is like cement, or a framework to stick things together.

Calcium-containing salts are the most important minerals to bones, making up around 70% of the matrix, including mostly calcium phosphate (hydroxyapatite, #Ca_5(PO_4)_3(OH)# ) and some amount of calcium carbonate and other calcium or phosphate salts. These provide rock-like rigidity, literally, as limestone is largely calcium carbonate. There are trace amounts of other minerals like magnesium, sodium and potassium, which lends metallic support.