Parathyroid Function

Question 1

what three organs does PTH have effect on?

Answer 1

Bone
Kidney
Gut

Question 2

what is the direct effect of PTH on bone calcium?

Answer 2

stimulates osteoclasts to increase bone resorption and increase calcium release

Question 3

what is the direct effect of PTH on kidney calcium?

Answer 3

increase tubular Ca reabsorption and increase vitamin D activation

Question 4

what is the indirect effect of PTH on gut calcium?

Answer 4

due to vitamin D activation from kidney the gut starts to absorb more calcium

Question 5

what is the direct effect of PTH on bone phosphorus?

Answer 5

increase bone resorption and increase phosphorus release

Question 6

what is the direct effect of PTH on kidney phosphorus?

Answer 6

increas phosphorus excretion, increase Vit D activation

Question 7

what is the direct effect of PTH on gut phosphorus?

Answer 7

increase phosphorus absorption via vit D activation

Question 8

what is overall effect of PTH on levels of phosphorus?

Answer 8

decrease levels

Question 9

what is overall effect of PTH on levels of calcium?

Answer 9

increase

Question 10

how does calcium regulate PTH release?

Answer 10

if calcium high then PTH down…negative feedback

Question 11

how does phosphorus regulate PTH?

Answer 11

positive feedback, if Phosphorus high then turns up PTH

Question 12

where is the majority of bodily calcium stored?

Answer 12

skeleton

Question 13

what percent of body calcium is in ECF ?

Answer 13

0.2%

Question 14

what three ways does calcium exist in ECF?

Answer 14

protein bound
ionized (free)
complexed with PO4 etc

Question 15

what protein often binds calcium?

Answer 15

albumin

Question 16

what is the bioactive form of calcium?

Answer 16

ionized free calcium in ECF

Question 17

if you have low albumin what can happen with measure of calcium?

Answer 17

can be low total calcium…but ionized calcium has not changed

Question 18

how does ionized calcium respond to alkalemia?

Answer 18

ionized calcium decreases as it binds with more albumin in alkalemia

Question 19

how does ionized calcium respond to acidemia?

Answer 19

ionized calcium increases because albumin bound Ca decreases

Question 20

does vit D increase or decrease phosphorus levels?

Answer 20

increases

Question 21

is phosphorus high or low in renal failure?

Answer 21

high

Question 22

what happens to PTH with low magneisum?

Answer 22

PTH release is blunted with low magnesium

Question 23

when creatinine is up, what does this usually mean?

Answer 23

chronic kidney disease

Question 24

if creatinine is going up during CKD, what is likely happening with phosphorus?

Answer 24

increased in serum because not excreted will by failing kidneys

Question 25

what happens to serum calcium in CKD, why?

Answer 25

serum calcium decreases because Vit D not being activated well by kidneys

Question 26

what happens to PTH in CKD? why?

Answer 26

elevated because increased levels of phosphorus and decreased calcium

Question 27

what two organs lead to Vit D activation? which is first and which is second?

Answer 27

first is liver and second is kidney

Question 28

what is the storage form of Vit D?

Answer 28

25-OH-D

Question 29

what is active form of Vit D?

Answer 29

1,25-OH2-D

Question 30

what is effect of clacitonin?

Answer 30

opposite of PTH…decrease calcium and increase phosphorus