Bone Basics

Question 1

What are the four functions of bones?

Answer 1

1. Supports weight.
2. Protection.
3. Mineral store.
4. Blood formation.

Question 2

What two types of bone are there?

Answer 2

Compact (cortical) and spongy (trabecular).

Question 3

How is compact bone structured?

Answer 3

In circular structures (osteons or Haversian systems). They surround a central Haversian canal and horizontal perforating Volkmann’s canals.

Question 4

What two components surround a Haversian canal?

Answer 4

Osteocytes and concentric rings of bone matrix (lamellae).

Question 5

How is spongy bone structured?

Answer 5

A network of lamellated trabeculae filled with bone marrow. Has no Haversian systems. The orientation of trabeculae reflects the main directions of mechanical forces.

Question 6

What three cells exist in bones?

Answer 6

Osteoclasts, osteoblasts and osteocytes.

Question 7

What components exist in the bone extracellular matrix?

Answer 7

Hydroxyapatite crystals and Type I collagen.

Question 8

What function do hydroxyapatite crystals have?

Answer 8

Makes the bone stiff for support; has high strength under compression.

Question 9

What function does collagen have?

Answer 9

Makes the bone flexible; has high strength under tension.

Question 10

What types of bone marrow are there?

Answer 10

Red - forms all blood cells except lymphocytes.
Yellow - primarily a storehouse for fats.