Calcium Flashcards
What is the UL for Ca?
2500mg
how much do you need a day to balance Ca lost in bone resorption?
250mg
if you have enough Vit D, you absorb ___
30% of 800 mg (the EAR)
passive absorption is about ___%
10
what proteins are involved in transport of Ca across the BBM?
Calbindin, Ca channels (TRPV6)
Passive transport involves ____ transport and diffusion
paracellular
What are inhibitors of calcium absorption?
other divalent cations (not from normal diet), unabsorbed f.a. that bind to Ca to make insoluble soaps, fibre, oxalic/phytic acid (bind divalent cations)
what are the three sites that PTH acts on during hypocalcemia?
bone (resorption=loss), kidney (reabsorption, ^1,25), small intestine (absorption)
what is the counter-hormone to calcitriol?
calcitonin (not much clinical importance)–>released after you eat
What is bone mineral called?
hydroxyapatite
Bone that is compact/dense, majority of bone in body, consists of collagen layers, found mainly on surfaces of all bones and as shaft of long bones
cortical bone
Type of bone that is spongy, where Ca is taken out from, matrix of collagen, found in axial skeleton and the ends o bones
trabecular bone
_____improve Ca solubility in the GI
Vitamin D, protein, sugars, sugar alcohols (fermented to acid)
What are nutrients that enhance urinary calcium excretion and decrease efficiency of reabsorption?
sodium, protein, caffeine
what nutrients are inhibited by excessive calcium?
phosphorus, iron, f.a.
____ prefers calcium, ___ prefers zinc
oxalate; phytate (found in cell walls)
insoluble soaps (f.a.+Ca) might protect against ____
colon cancer
Why is spinach calcium poorly absorbed?
because it contains oxalate
approximately ___ % of plasma Ca is reabsorbed by kidney nephrons
98 (PTH ^ reabsorption efficiency)
how does excess protein cause ^ acid production?
Cystein and Methionine produce H2SO4
what is the RDA? What s the EAR?
1000mg; 800mg
what are the two ways to measure calcium balance?
in=out; DXA (dual xray absorpiometry)–>change in bone mineral amount over time
amenorrhea is associated with
anorexia nervosa
the UL for Ca is set to prevent this
kidney stones
What is the LOAEL?
2000 mg
condition of soft tissue calcification
milk-alkali syndrome
high intakes of Ca pose controversial risk of ___ and ____ in men
heart disease; prostate cancer
