Calcium + Phosphate

Question 1

Vitamin D active isoform?

Answer 1

1,25-OH-VitD (Calcitriol)

Question 2

Vitamin D effect on Ca++ and PO4- on intestines?

Answer 2

1. ⬆️Reabsorption

Question 3

Alkalosis promotes what to Ca++ levels?

Answer 3

1. ⬆️Protein binding

2. ⬇️Hypocalcemia

Question 4

Acidosis effect on Ca++ levels?

Answer 4

1. ⬇️Protein binding

2. ⬆️Hypercalcemia

Question 5

⬆️ Ca++ and PO4- levels induce this effect on bone?

Answer 5

1. Bone deposition (mineralization)

Question 6

⬇️Ca++ and PO4- levels induce this in bones?

Answer 6

1. ⬆️Bone resorption (demineralization)

Question 7

This hormone deactivates RANK-L?

Answer 7

1. Osteoprotegerin (OPG)

2. ⬇️Osteoclastic activity

Question 8

Ligand that ⬆️osteoclastic activity?

Answer 8

1. RANK-L

Question 9

Estrogen effect on bone activity?

Answer 9

1. ⬇️Osteoclastic activity
2. ⬆️OPG synthesis —> Blocks RANK-L
3. ⬇️T-lymphocyte activity

Question 10

Glucocorticoid effect on bone?

Answer 10

1. ⬆️Osteoclastic activity
2. ⬆️RANK-L synthesis
3. ⬇️OPG

Question 11

PTH actions ?

Answer 11

1. ⬆️Hypercalcemia
2. ⬆️Phosphate secretion in kidneys
3. ⬆️1alpha-hydroxylase activity
4. ⬆️VitD
5. ⬆️Ca and PO4- absorption in GI system

Question 12

Main PTH ⬆️stimulus?

Answer 12

1. Hypocalcemia ⬇️

Question 13

Main Calcitonin ⬆️ stimulus?

Answer 13

2. Hypercalcemia ⬆️

Question 14

Where is Calcitonin secreted ?

Answer 14

Parafollicular Cells (C Cells) of the thyroid

Question 15

Vitamin D isoform absorbed in skin?

Answer 15

1. Vitamin D3 (cholecalciferol)

Question 16

Enzyme in the liver in charge of converting Vit D precursors into 25-OH-VitD ?

Answer 16

25-hydroxylase (Liver)

Question 17

Where is 1alpha hydroxylase located at?

Answer 17

1. PCT of Kidney

Question 18

What does an excess Vitamin D cause ?

Answer 18

1. ⬆️Bone Resorption