Calcium, Hormones, and Bones PTH, Calcitonin, Calcitriol, Growth Hormone, Estrogen, Testosterone

Factors Regulating Bone Growth Ions: – Calcium, phosphate, magnesium, citrate, carbonate, sodium Vitamins: – Vitamins A and C – Vitamin D derivatives

Hormonal Control of Bone Tissue Sex Hormones: (estrogen, progesterone, testosterone) Calcitriol: Human Growth Hormone (hGH): Thyroxine: Calcitonin: Parathyroid Hormone: Stimulate Osteoblasts (Bone Growth) Inhibits Osteoclasts Stimulates Osteoclasts (raise blood Calcium) Increases Ca 2+ absorption from intestine.

Calcitriol- Active Form of Vitamin D Increases Calcium absorption in the GI tract Increases calcium reabsorption by the kidneys May increase release of calcium from the bones by stimulating activity of osteoclasts Raises level of Calcium in the Blood- Good for Muscles, Nerves

Production and Regulation of Calcitriol Synthesized in the kidney inactive vitamin D converted to active form PTH (parathyroid hormone) stimulates production of Calcitriol Blocks the activity of Calcitonin (keeps Calcium in bone-stronger bones)

Case Study- Application Aunt Sarah recently fell and fractured her hip. It was a closed and comminuted fracture. The doctors determined that Aunt Sarah has osteoporosis and explained that there is a risk that future falls would also result in broken bones

Questions 1.Describe the fracture what do the terms ‘closed’ and ‘comminuted’ mean about the fracture? 2.what can you conclude about the relative activity of her osteoblasts versus her osteoclasts?

Questions 1.Docs recommended that Nancy take calcitriol. Name the condition that normally results in an increase in this hormone’s production. What does the name of this condition mean? 2.Describe the effects (if any) that calcitriol has on osteoblasts and osteoclasts, and explain how each of these effects occurs

Questions 1.Do you think that calcitriol alone will ‘fix’ Nancy’s osteoporosis? Explain your answer. 2.Nancy’s daughter was the one who called the paramedics. Is Nancy’s daughter at risk for developing osteoporosis? If so, what can she do to help prevent osteoporosis from developing.