The biology of the skeleton
Bone is more complex
than you might think!
Some of the many functions of bone:
-Protection of organs
-Mineral storage
-Making red and white blood cells
-MOVEMENT!
What kinds of bone are there?
Cortical
bone
Spongy
What is bone made of?
Mineral (calcium phosphate)
 Organic molecules (like type I
collagen)
 CELLS

– Osteoblasts
– Osteoclasts
– Osteocytes
Bone cells
“Osteo” means “bone” in Greek
 Bone cells are responsible for forming and
remodeling your skeleton

Osteoclasts
Osteoblasts
Osteocytes
Bone eating cells
Bone forming cells
Osteoblasts that became
trapped in the newly
made bone.
new
bone
Bone Surface
Bone Surface
Bone Surface
Your bones require
MECHANICAL LOAD
to stay strong
What happens when your bones
AREN’T strong?
•Osteoclasts are doing
more work than
osteoblasts!
•The osteoclasts are
breaking down more
bone than osteoblasts
are making.
Bone resorption > Bone formation
BONE LOSS!!!
How can we FIX osteoporosis?
Bone resorption > Bone Formation
BONE LOSS
Osteoporosis!
Bone resorption < Bone Formation
osteoblast
osteoclast
BONE GAIN
Does the behavior of cells in the bone
change depending on what surrounds it?
Can we force
osteoblasts to make
MORE BONE by
changing the
surroundings of the
cell?
Techniques I use…
Cell culture
 Microscopy

– Atomic Force
Confocal Microscopy
Microscopy
– Confocal Microscopy
AFM
RGDS peptide (20 g/ml)
Fibronectin (5 g/ml)
Type I Collagen (5 g/ml)
400
[Ca2+]i (nM)
Calcium imaging
 Reporter assays

300
200
100
0
0
addition of
soluble ECM
2
4
6
8
10
Time (minutes)
Calcium Imaging
12
14