osteoporosis Flashcards
role of calcium (alot)
o Regulation of cell membrane permeability and functions, neuronal excitability and transmission of electrical impulses
o Contraction of cardiac, skeletal, and smooth muscle
o Conduction of electrical impulses in the heart
o Blood coagulation
o Platelet adhesion
o Hormone secretion
o Enzymatic activity
o Catecholamine release from the adrenal medulla
o Release of chemical mediators – histamines from mast cells
o Required for maintaining healthy bone and teeth
what is the function of the bone?
structural support and reservoir for calcium and phosphate
what is resorption
when serum levels are low in calcium, calcium will move from bone to blood stream
when will calcium move from bone to blood stream
if serum levels are low in ca
deposition
calcium from the intestines moves from diet onto bone
when does calcium move from intestines onto bone
when calcium on bone is not adequate
what is calcium deficiency caused by?
poor diet, hormonal altercations, medications
when someone is calcium deifcient, calcium moves from bone into the serum to compensate (resorption) what might this result in?
loss of bone mass, structural function and osteoporosis
what three hormones regulate calcium metabolism
PTH, Calcitonin, calcitriol
parathyroid hormone is secreted from what gland?
parathyroid gland
when are the parathyroid glands stimulated?
when calcium levels fall below normal
how does parathyroid hormone work to increase calcium resorption in kidneys
increases resorption in the renal tubules, reducing the amount in the urine, increasing amounts in serum
how does PTH increase the absorption of calcium in the small intestines
pth –> metabolism of vitamin d –> calcitriol
increases the absorption of calcium in the intestines
what is the active form of vitamin d
calcitriol
how does pth metabolize vitamin D into calcitriol
stimulates the metabolism of vitamin D into the active form
where is calcitonin form?
thyroid gland
when is calcitonin secreted
when calcium levels rise
when calcium levels rise what is secreted
calcitionin
how does calcitonin work in bone?
inhibits the activity of osteoclasts, stimulating the rate of bone deposition so calcium moves from serum to bone
what stimulates calcium to move from serum to bone
calcitonin
how does calcitonin work in the kidneys
works to inhibit resorption of calcium in the renal tubules –> more calcium excreted in the urine
what allows for more calcium to be excreted into the urine
calcitonin
what is called calcifdediol in the liver
calcitonin
when is vitamin d synthesized into its active form calcitriol
when serum levels are low