Lab #3 (exercise 7-2)

What are the two chemical components of bone ECM?

Organic matrix and inorganic matrix.

What is the organic matrix also called?

Osteoid.

What percentage of bone ECM is approximately organic matrix?

About 35%.

What is the organic matrix mostly made of?

Collagen fibers.

What produces the organic matrix?

Osteoblasts.

What does collagen in the organic matrix provide?

Tensile strength.

What is tensile strength?

The ability to withstand stretching and twisting forces.

Why is tensile strength important in bone?

Muscle contractions can twist and stretch bones.

What is the inorganic matrix mostly made of?

Calcium hydroxyapatite crystals.

What percentage of bone ECM is approximately inorganic matrix?

About 65%.

What does the inorganic matrix provide?

Compressional strength.

What is compressional strength?

The ability to withstand compressive forces.

Why is compressional strength important?

It allows bones to withstand forces from body weight.

What are calcium hydroxyapatite crystals?

Mineral crystals that make up most of the inorganic matrix of bone.

What is osteoid?

The unmineralized organic portion of bone matrix.

What would happen if bone lacked enough collagen?

It would have reduced tensile strength and would be less able to withstand stretching and twisting.

What would happen if bone lacked enough calcium hydroxyapatite?

It would have reduced compressional strength and would be less hard.

Which component gives bone flexibility/tensile strength?

Organic matrix, especially collagen fibers.

Which component makes bone hard and resistant to compression?

Inorganic matrix, especially calcium hydroxyapatite crystals.