block 5 lecture 5 bone metabolism Flashcards
what percentage is organic bone material?
40%
what percentage is inorganic bone material?
60%
what is the organic materials of bone?
type 1 collagen and non-collagenous protein
what is the inorganic portion of bone?
calcium hydroxyapatite
what is trabecula bone?
cancllous and spongy bone
what are osteoclasts?
multi nucleated cells formed from many monocytes
what can increase the resorption of bone by an osteoclast?
bigger osteoclasts perform more aggressive resorption of bone
how do osteoclasts adhere to the bone matrix?
by forming lipid like adhesions and express strong intergrin interactions
what do osteoclasts do?
secrete enzymes and acids to degrade matrix
what happens to degraded bone material by osteoclasts?
shoots up through apical membrane and removed from the cell
what are the osteoclast resorption pits called?
howships lacuna
what are osteoblats?
mononucleated stromal cells
what do osteoblasts come from?
mesenchymal cells
what do osteoblasts do?
mineralize bone matrix to replace removed bone
what do osteoblasts form into?
osteocytes
what do the extesions of osteocytes make connections with?
the bones surface and other osteocytes
what do the processes of osteocytes act as?
mechnosensors
hat stops osteoclasts resorbing?
reversal stage
what is the matrix that osteoblasts lay down?
type 1 collagen and non colagenous protein
what is the bone matrix called when it is initially laid down?
osteoid
what are some signals involved in bone growth?
parathyroid hormine, vitamin D, calcitonin, growth hormone, growth factors, oestrogen, cytokines
what is the calcuim resevoir?
skeleton
what are the three fractions of calcium in serum?
ionised calcium, protein bound calcium and complexed calcium