Author, Donkey, Bureaucrats, Administrators
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Bone Response to Damage (view source)
Revision as of 08:06, 10 October 2007
, 08:06, 10 October 2007no edit summary
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***Promoted by growth factors
***Promoted by growth factors
***Have receptors for PTH
***Have receptors for PTH
+****They contract in response -> space for osteoclasts to attach
**'''Osteocytes'''
**'''Osteocytes'''
***Osteoblasts that have become surrounded by mineralised bone matrix
***Osteoblasts that have become surrounded by mineralised bone matrix
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***Regulate composition of bone fluid
***Regulate composition of bone fluid
**'''Osteoclasts'''
**'''Osteoclasts'''
−***Large, often multinucleated cells
+***Histologically:
−***Acidophilic cytoplasm
+****Large, often multinucleated cells
+****Acidophilic cytoplasm
***Derived from haematopoietic stem cells
***Derived from haematopoietic stem cells
−***Responsible for bone resorption (have a brush border for this)
+***Responsible for bone resorption
+****Firstly dissolve mineral followed by collagen
+****Use brush border for this
***Sit in bone surface depression - '''Howship's lacuna'''
***Sit in bone surface depression - '''Howship's lacuna'''
+***Do <u>not</u> have receptors for PTH
+***Have receptors for calcitonin
+****Involute their brush border in response
+****Detach from bone surface
*'''Matrix''':
*'''Matrix''':
**Osteoid
**Osteoid