Question

In a cross section of a bone, you can usually see two types of bone tissues. What are these called?

Answer 1

Compact bone & Spongy bone.

Explanation:

In a cross section of a bone we can see two types of bone tissue: spongy bone and compact bone. Compact bone is the outer layer and the spongy bone forms the inner layer.

Figure 1 : Two types of bone tissues in cross section of a long bone :

As the names suggest compact bone looks compact and the spongy bone looks like sponges. There are trabeculae in spongy bone which gives its sponge like appearance.

The compact bone is made up of osteon. The osteon has blood vessels and bone cells, things vital for the survival of the bone.

Figure 2 : The spongy and compact bone tissue in the cross section of a skull bone. Skull bone is a flat bone. We can see there are two layers of compact bone here. Whereas a long bone has only one layer of compact bone (see fig 1).