Parathyroid

Question 1

What is the precursor to vitamin D

Answer 1

cholecalciferol

Question 2

Cholecalciferol is converted to 25 hydroxycholecalciferol in the ____

Answer 2

Liver

Question 3

_______ causes the conversion of 25 hydorxycholecalciferol to 1, 25 dihydrocholecalciferol in the _______

Answer 3

PTH; kidney

Question 4

What does vitamin D bind to in order to increase Ca absorbsoption

Answer 4

Retinoid X receptor

Question 5

What does moderate and excessive vitamin D do

Answer 5

Moderate-bone calcification

Excessive-bone resorption

Question 6

Cancer cells can secrete parathyroid like hormones which leads to what

Answer 6

Hypercalcemia, bone resoprtion

Question 7

What is the rapid effect of PTH

Answer 7

Increases Calcium pump at osteolytic membrane

Question 8

What is the effect of long term PTH

Answer 8

Receptors on osteoblasts to release RANKL and M-CSF and inhibit OPG

Question 9

What is the effect of the parathyroid on phosphate

Answer 9

Frees phosphate

Question 10

Low calcium = _____________ of parathyroid

Answer 10

Hypertrophy

Question 11

Calcium sensing receptor is what kind of receptor

Answer 11

G protein coupled, IP3, DAG

Question 12

What does calcitonin do

Answer 12

Inhibits osteoclasts, produced by C cells, secreted in response to hypercalcemia

Question 13

Hypercalcemia, hyperphosphaturia, depression of nervous system, renal stones

Answer 13

PTH hypersecretion

Question 14

Hypocalcemia and tetany

Answer 14

PTH hyposecretion

Question 15

Cushing syndrome: ______ACTH, _______ osteoclasts, ________ osteoporosis

Answer 15

High, high, high

Question 16

What molecule is the self limiting step of Ca regulation

Answer 16

25 hydrocholecalciferol (D3) that is why this is what is prescribed in response to hypocalcemia