The need for tissue engineering
Osteoporosis
The importance of calcium
- Serum Ca is maintained at a few millimoles/liter
- Controlled by hormones acting on bone, kidney and intestines
- If blood Ca is too low nerves become more excitable, but
transmission may be blocked at synapses- the net effect is muscular
spasms which can be fatal if they involve respiration
- Intracellular Ca levels are kept low by active transport:
- Keep cytoplasmic Ca at a concentration a thousand times lower than serum Ca (about 0.1 micromoles/liter)
- Necessary because high levels of cytoplasmic Ca kill cells- they
activate enzymes that destroy proteins and other cell components