List the four types of cells in bone tissue and their functions.

Osteogenic cells are hanging around waiting to deal with traumas or problems with the bone where they will have to produce new bone or strengthen the bone after a fracture or other trauma.

Osteoblasts are mainly responsible for bone generation and maintaining the strength of the bones, their decreasing presence is one reason for problems with bones in elderly folks.

Osteocytes maintain healthy bone tissue.

Osteoclasts are cells that actually help to break down bone tissue as the bone changes during its lifetime.  They are essential to healthy bones.