bone histology

what is the name of the cell that forms bones

osteoblast

what is the name of the cell that maintains the structure of the bone after formation

osteocyte

what is bone called when it is first secreted from the osteoblast

osteoid

how is osteoid mineralized

collagen binds with calcium hydroxyapatite

what cell dissolves the boney matrix

osteoclasts

where are osteocytes housed within the bones and how to they communicate with each other

They are house in lacuna and communicate through canaliculi

how are osteoclasts able to break down the boney matrix

through the secretion of carbonic anhydrase

on a macroscopic scale what are the two types of bone

• cortical bone

• trabecular bone

on a microscopic scale what are the two types of bone

• woven bone

• lamellar bone

what is woven bone

it is rapidly produced immature fragile bone

what is lamellar bone

mature organized bone

what is the outer layer of the bone called

periosteum

what are the two sections of the periosteum

• fibrous layer

• osteogenic layer

inside the bone itself what is the lining called

endosteum

what are the functional units of bone called

Osteons

what do osteons do

contain blood vessels, nerves and other cells

what type of bone contains osteons

cortical bone

what are the tunnels in osteons called

haversian canals

what connects two osteons

volkmann’s canal

what are secondary osteons

these are osteons formed on top of preexisting osteons

how are secondary osteons formed

a tunnel is dug with osteoclasts and new bone is formed by a lagging edge of osteoblasts and maintained by osteocytes

what does the bone as an organ do

• facilitates normal growth

• regulates mineral homeostasis

• adapt to stress

• repairs microinjuries

• responds to macroscopic injuries

what is modeling of a bone

the process in which a bone changes shape

what is remodeling of a bone

the process in which an old bone is replaced by new bone

why is remodeling necessary

• normal growth

• repair of wear and tear

• to accommodate moving vasculature

• mineral homeostasis

what are the two types of embryonal bone formation

• membranous ossification

• endochondral ossificatoin

what bones utilize membranous ossification

flat bones

what bones use endochondral ossification

long bones

what type of bone is formed through membranous ossification

cortical bone

what type of bone is formed though endochondral ossification

trabecular bone

what are the steps of membranous ossification

• primitive mesenchyme

• differentiates into osteoblasts

• lays bone on top of old bone

what are the zones in endochondral ossification

• zone of reserve cartilage

• zone of proliferation

• zone of hypertrophy

• zone of calcification

where does endochondral ossification take place on a long bone

at the physis

what type of cartilage is present at articular surfaces and physes

hyaline cartilage

what type of cartilage is present at the attachment point of tendons and ligaments

fibrocartilage

what cartilage is present in the ear and nose

elastic cartilage

what is the name of the cell that produces cartilage

chondrocytes