Bone Flashcards
4 main functions of bone
- Structural support
- Levers for muscles (locomotion)
- Protect organs - house marrow
- Metabolic reserve for minerals
Matrix of bone (2 main components)
Inorganic matrix and Organic matrix
What % of dry weight is Inorganic Matrix
65%
Components of Inorganic Matrix
Hydroxyapatite
Calcium phosphate
Other minerals
What % of dry weight is Organic matrix
35% (can be called Osteoid)
Components of Organic Matrix (3)
Collage (Type I)
GAG’s
Glycoproteins
Collagen of Organic Matrix is primarily what type?
Type I
Collagen is roughly what % of Organic Matrix
80-90%
2 types of GAGs w/in Organic Matrix
sulfated and nonsulfated
Sulfated GAGs w/in Organic Matrix (2)
chondroitin and keratin
Nonsulfated GAG w/in Organic Matrix
hyaluronic acid
Glycoproteins w/in Organic Matrix
proteins that bind minerals to collagen = binding proteins
proteins that bind matrix to cells (sialoprotein)
Bone cells (5)
Osteoprogenitor Osteoblast Osteocyte Bone-lining cell Osteoclast
Osteoprogenitor appearance
flat
Osteoprogenitor location
endosteum and periosteum
Osteoprogenitor: derived from
usually mesenchyme cells
possibly chrondrogenic cells
Osteoprogenitor: function
to supply osteoblasts
Do Osteoprogenitors undergo mitosis?
YES
Osteoblast appearance
cuboid to columnar
Osteoblast locations
endosteum and periosteum
Osteoblast: derived from
osteoprogenitors
Osteoblast: functions
- formation of bone
- produce materials (matrix vesicles) which initiate calcification of newly produced bony matrix
- respond to PTH
Osteoblast response to PTH
- secrete OPGL - initital creation of more osteoclasts
- secrete osteoclast-stimulating factor
- produce enzymes to condition bone surface for osteoclasts
Do osteoblasts undergo mitosis?
NO
