Bone Flashcards
What is woven bone?
Immature or primary bone that will eventually be replaced by lamellar bone
What are the characteristics of woven bone?
Loose arrangement of collagen fibers, more cells and less mineral content, forms during fx repair or remodeling
What is lamellar bone?
mature or secondary bone
What are the characteristics of lamellar bone?
Regular parallel arrangement of collagen fibers, not visible on HE stains, found in adult bones- strong and forms slowly
What are osteoprogenitor cells?
cells of mesenchymal origin with stem cell properties- proliferate and differentiate
Where are osteoprogenitor found and what do they give rise to?
found in the inner layer of periosteum and endosteum. They give rise to osteoblast
what are osteoblast?
they are cells that deposit osteoid and control mineralization of osteoid- they give rise to osteocytes
What do osteoblast look like?
epithelial-like cells with cuboidal or columnar shape
What are osteocytes?
cells in the lacunae that are highly branched to allow them to get nutrients. They are responsible for laying down matrix of bone
What are osteoclast?
Generate a seculded acidic enviroment for bone resorption- mediated by H+atpase that degradation of organic matrix via cathespin K protease
What do the osteoclast derive from?
a monocyte- macrophage lineage
What are the periosteum and endosteum?
They provide nutrition to the bone- continuous supply of new cells for growth and repair- peristeoum is not at articular surfaces
What are the two layers of the periosteum?
inner- has osteoprogenitor cells
and outer layer- rich in blood vessels/nerves, fibroblast and collagen and Sharpey’s fibers
What is the endosteum?
covers the spongy walls, extends into all cavities of bone- osteoprogenitor cells present
What is the osteon?
Also known as the Haversian Systems- Concentrically arranged lamellae around a longitudinal vascular channel
