Exam 1 bone basics Flashcards
osteoblasts derive from what
osteogenic stem cell
osteoclasts derive from what
hematopoietic stem cell
which cell interacts with calcitonin and what does calcitonin do
osteoclasts interact with it and then calcitonin increases calcium storage to increase bone formation
what does vitamin D do
increases bone remodeling via RANKL and OPG
what does estrogen do
increases OPG
what does cortisol do
it increases RANKL and decreases OPG
what is endochondral ossification?
growth of long bones
- occurs at metaphysics where hyaline cartilage is made and then replaces by mature bone via osteoblasts
what is intramembranous ossification?
growth of flat bones
what is the matrix of the osteoid mostly made of
type 1 collagen
what are the cofactors and enzyme for making type 1 collagen
cofactor: vitamin C
enzyme: lyslhydroxylase and prolysylhydroxylase, add OH groups to lysine and proline to coil collagen
what is the nucleation of bone mineralization?
when the helices of collagen cross link to become fibers (coil of 3 strands)
what does osteocalcin protein do?
binds Ca++ and hydroxyapatite
what does ostenectin protein do?
binds hydroxyapatite and collagen and promotes mineralization of collagen
what is hydroxyapatite?
requires alkaline phosphatase which promotes mineral deposition
what does parathyroid hormone do?
binds osteoblasts and causes them to release RANKL
