Role of the haversian canal, osteocyte and canaliculi?

What is the role of the haversian canal, osteocyte and canaliculi in keeping osteocytes alive despite being surrounded by bone

By means of these canaliculi, nutrients and waste products are exchanged to maintain the viability of the osteocyte. Osteocytes are the most abundant type of cell in mature bone tissue. They also are long-lived, surviving as long as the bone they occupy exists.