Calcium and Bone Flashcards Preview

Physiology Exam IV > Calcium and Bone > Flashcards

Flashcards in Calcium and Bone Deck (30)
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1
Q

how does vit D affect calcium

A

stimulates calcium absorption, increases plasma conc

2
Q

how does vit D affect phosphate

A

stimulates phosphate absorption (but less than Ca++) increases plasma conc

3
Q

how does PTH affect plasma calcium

A

increases

4
Q

how does PTH affect plasma phosphate

A

decreases

5
Q

why does PTH decrease phosphate

A

to prevent Ca++ and phosphate binding and forming crystals

6
Q

how does calcitonin (CT) affect plasma calcium

A

decrease

7
Q

how does CT affect plasma phosphate

A

decrease

8
Q

how does PTH affect kidney

A

controls amount of Ca++ reaborbed in distal portions of nephrone
inhibits phosphate reabsorption in kidney

9
Q

How does PTH affect bone

A

increases bone resorption and delivery of calcium to plasma

inhibits collagen synthesis by osteoblasts

10
Q

how does PTH affect vit D

A

it increases vit D by increasing activity of 1alpha hydroxylase.

11
Q

How does Vit D affect PTH

A

inhibits

12
Q

what are the plasma forms of calcium

A

free or ionized
protein bound
bound to small diffusible anions

13
Q

where is more than half of the total caclium found

A

free or ionized

14
Q

symptoms of hypocalcemia

A

easier to have APs, so everything is more excitable

15
Q

what signs clue you into hypocalcemia that causes latent tetany

A

trousseau or chyvostek

16
Q

symptoms of hypercalcemia

A

less likely to have an AP. also polyuria and kidney stones

17
Q

osteoblasts

A

deposit bone

18
Q

osteoclasts

A

resorption of bone

19
Q

osteoprotegerin ligand (OPGL) is also called

A

RANK ligand

20
Q

function of OPGL

A

activates receptors on preosteoclast cells, causes them to differetiate into multinucleated osteoclasts

21
Q

osteoprotegerin (OPG) function

A

acts as a decoy receptor of OPGL, prevents it from biding to its receptor on preosteroclast cells

22
Q

how does PTH affect bone resorption

A

stimulates bone resoprtion by binding to receptors on osteoblasts and causing them to release OPGL

23
Q

where is vitD3 converted to active form

A

kidney

24
Q

what is the active form of vitD called

A

1,25 dihydrorycholecalciferol

25
Q

osteomalcia

A

can be due to failure of damaged kidney to produce the active form of vit D

26
Q

signs of primary hyperparathyroidism

A

hypercalcemia, hypophosphatemia

27
Q

symptoms of primary hyperparathyroidism

A

formation of calcium containing kidney stone
weak bones
constipation, excessive urination

28
Q

when does secondary hyperparathyroidism happen

A

pt with disease that cause chronically low plasma calcium

29
Q

symptoms of hypoparathyroidism

A

low calcium causes neuromuscular hyperexitability, hypocalcemic tetany

30
Q

pseudohypoparathyroidism

A

have signs and symptoms of hhypoparathyroidism but their circulating level of PTH is normal or elevated