Lecture: Bone Formation and Growth Flashcards
Osteoprogenitor Cells
stem cells found in the endosteum and cellular periosteum
pluripotent squamous cells that give rise to osteoblasts
Osteoid
New uncalcified bone matrix
Osteoclasts
large
many nuclei
eosinophilic cytoplasm
monocyte lineage
inhibited by calcitonin
activated by parathyroid hormone (PTH)
Cutting cone
part of the remodeling unit that contains osteoclasts
Closing cone
part of the remodeling unit that contains osteoblasts and osteoprogenitor cells
Howship’s Lacuna
aka resorption bay
contained within the sealing zone
pH of 4.5
Clear zone
seals off Howship’s lacuna to prevent it from spreading
has actin filaments and adhesion molecules
Osteomalacia
-Insufficient calcium and/or Vitamin D
-Lack of mineralization
-Softened bone, bowed legs
Osteopetrosis
-Over mineralized bone
-Defective osteoclasts
-Dense, but fragile bone
Epiphyseal Plate
growth plate that allows growth into early adulthood. Contains cartilage that is being replaced by bone which gives growth.
Resting zone, Proliferation, Maturation & Hypertrophy, Degeneration & Calcification, and Ossification
Mnemonic: Real Peace Makes Days Optimistic
Trabecular bone
Also known as spongy or cancellous bone, it has a porous, lattice-like structure. It consists of a network of trabeculae (thin, bony struts) that create spaces filled with bone marrow.
Intramembranous Osteogenesis
osteoblasts differentiate from mesenchyme
ex: Flat bones of skull and face, mandible, clavicle
Endochondral Ostegenesis
osteoblasts invade and ossify a
hyaline cartilage forerunner
ex: Long bones of the appendicular skeleton and vertebrae
Epiphyseal Line
-What the epiphyseal plate turns into
-Hardened by bone and no longer contains cartilage
-No more growth of the long bone
Interstitial bone growth
At the epiphyseal plate
Lengthens bones
