Test 1

Question Answer
What is the formal name for the mineral calcium? hydroxyapatite
Where is 99% of calcium found in the body? bone, teeth
How is Ca transported across the intestinal epithelia? active transport using Ca binding proteins
Where is Ca absorbed the most? duodenum and jejunum
When is calcium uptake more active? When calcium levels in the body are high or low? When calcium levels are low
What form of vitamin d has the most influence on calcium absorption in the intestines? calcitriol (D3)
When Ca concentrations are very high what is another way calcium gets across the intestinal membrane of the ileum and the colon? When concentrations are very high it just diffuses paracellularly
What are some physiological factors that affect Ca absorption? vitamin D status,
life stage (infancy pregnancy and old age),
inhibition of absorption
In general how does vitamin d status affect Ca absorption (increasing and decreasing) too little vit d can't absorb Ca, too much vit d absorb too much Ca and have hypercalcemia
what are some inhibitors of Ca absorption phytic acid, oxalic acid, fat malabsorption, high intake of other divalent cations (Mg2+, Fe2+)
what are some factors that would increase the absorption of Ca
How is Ca transported in the blood protein bound (albumen), free ionized form, bound to P.C.S. (phosphate, citrate, sulfate)
Which way does Ca transport through the blood the most Free ionized form
How is Ca excreted Urine, feces, sweat
What are the major functions of Ca in the body Structural, muscle contraction, blood clotting, nerve conduction
What is PTH's effect on the kidney PTH causes increased activity of 25 hydroxylase which converts calcidiol to calcitriol, increases reabsorption of Ca and excretion of P
What is PTH's effect on bones PTH stimulates osteoblast activity to indirectly increase osteoclast activity causing an increase in resorption
What are the effects of vitamin d on the kidneys increased expression of calcium binding protein (calbindin), increased reabsorption (Acts on the tubules in the kidneys to reabsorb calcium from the pee)
What are the effects of vitamin D on bones interacts with osteoblasts to indirectly stimulate osteoclast activity (increased bone resorption)
What are the effects of vitamin D on the intestines interacts with enterocytes to increase expression of calbindin and increase the expression of transporters for calcium in and out
osteoblasts have receptors for ______ hormone and osteoclasts have receptors for ____ hormone PTH, calcitonin
Vitamin D has an effect on ___ absorption in the intestines, where PTH has no effect Ca
What is the hormone that is released in response to high calcium levels (or hypercalcemia) and which organ secretes it calcitonin, thyroid
Name 2 effects of calcitonin inhibits PTH secretion, decreases the activity of osteoclasts
What are some deficiency symptoms of hypocalcemia muscle pain and spasm, osteoporosis (theres more just fyi)
What are some possible causes of hypocalcemia renal disease, liver disease, parathyroid issues (hypoparathyroid), low vitamin D status, malabsorptive disorders
What are "Bones, stones, moans, and groans” symptoms for hypercalcemia
What does bones, stones, moans, and groans stand for Bone: ache, high risk of fracture (impair normal bone turn over), Stones: kidney stones: inappropriate deposition in the kidney, Moans: muscular, groans: neurological issues
What are some causes of hypercalcemia vitamin D toxicity, over active parathyroid (hyperparathyroidism), cancer
What are good food sources of Ca dark leafy greens, dairy, beans
the distribution of phosphorus in the body is: bones, muscles, blood
Where is phosphorus mainly absorbed and by what means duodenum and jejunum, by phosphate transporters
Is phosphorus influenced by vitamin d yes but not as much as Ca
How is phosphorus transported in circulation lipoproteins
How is P regulated and what organ also has regulatory effects on it regulated by PTH and the kidney regulates it by excreting and reabsorbing
What are some functions of phosphorus in the body need it in every cell of our body: phosphorylations, energy production and storage (ATP), phospholipid membrane, cell signaling, bones
is deficiency common No very rare, present in most foods
What is one disease state where P is crucial to include Malnurished person refeeding syndrome where if they have glucose w/o P
Why is it so crucial to have P with glucose in feeding tubes Because the first step glucose goes through when it enters cells is it has to be phosphorylated and without P you can undergo metabolic stress and die
What are common foods containing P dairy, legumes, nuts, grains
What are some factors that have an increasing effect on Ca absorption acidic environment, lactose, protein, amount ingested, low calcium status, vit d
What are factors that have a decreasing effect on Ca absorption citric acid, oxalic acid, low vit d, malabsorption of fat, foods high in competing divalent cations

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