14: Hormones of Calcium Metabolism- Schmidt

Question 1

make bone

Answer 1

calcium chloride + sodium phosphate = calcium-phoshpate

Question 2

pseudogout =

Answer 2

calciumphosphate crystals in the joint when the ions reach critical concentrations

Question 3

what enzyme activities need calcium directly? indirectly?

Answer 3

citric acid cycle and glycogen degradation

indirectly - calmodullin

Question 4

calcium is essential for …

Answer 4

blood coagulation and muscle contraction

required also for the stability of bone

Question 5

in serum, about ______% calcium is free and ____% bound to prtns or small molecules

Answer 5

50/50

only free calcium is physiologically active

Question 6

goal of calcium pool regulation

Answer 6

keep calcium concentration in ECF constant

Question 7

calcium and______ are regulated inversely

Answer 7

phosphate

ex: mobilization of bone calcium is accompained by increase in phosphate excretion. also high phosphate intake leads to increased calcium excretion

Question 8

stimulates calcium uptake in the gut

Answer 8

calcitriol

Question 9

stimulates resorption of bone calcium into the serum and stimulates synthesis of calcitriol in kidney

Answer 9

PTH

Question 10

stimulates calcium excretion by the kidney

Answer 10

calcitionin

Question 11

“calcistat”

Answer 11

the calcium stasis system

drawn out in notes with effects of PTH and CT

Question 12

PTH is synthesized…

Answer 12

in the chief cells of the parathyroid glands

Question 13

calcitonin is synthesize in….

Answer 13

the thyroid glands

Question 14

CT and PTH are both

Answer 14

peptide hormones

Question 15

binding of PTH to receptors leads to activation of…

Answer 15

• the cAMP/PKA pathway

- the phospholipase C/ Prtn Kinase C pathway

Question 16

what are the actions of PTH in the kidney?

Answer 16

• increases resorption of Calcium in the distal tubule, the collecting duct and the ascending limb of the loop of Henle
• stimulaes phosphate excretion
• stimulates synthesis of calcitriol

Question 17

effects of PTH in bone

Answer 17

stimulates the resorption f calcium by osteoclasts

Question 18

calcitonin acts through…

Answer 18

g-prtns and signal via cAMP levels

Question 19

physiological actions of calcitonin

Answer 19

bone - inhibits resorption of calcium

kidney - stimulates calcium excretion

Question 20

calcitriol is synthesized from

Answer 20

cholesterol

so it is awater-insolluble steroid derivative

calcitriol synthesis involves skin, liver and kidney (in this order)

Question 21

target organs of calcitriol

Answer 21

intestine
bone
kidney

stimulates the transcription of calcium binding prtns, calcium ATPase, facilitators of vesicle formation

Question 22

low vitamin d levels or insufficient calcium intake

Answer 22

ricketts/osteomalacia

osteoid matrix and cartilage are formed, but not minearlized leading to soft, pliable bones

Question 23

kidney disease leads to calcium loss in urine, insufficient calcitriol production

Answer 23

renal osteodystrophy

Question 24

GH effects on calcium homeostasis

Answer 24

stimulates bone remodeling

Question 25

glucocorticoids effects on calcium homeostasis

Answer 25

• reduce absorption from GI
• decrease calcium reabsorption
• inhibit bone formation
• stimulate PTH secretion

Question 26

estrogen effects on calcium homeostasis

Answer 26

• increase calcium reabsorption from kidney

- inhibit PTH mediated bone resorption