A brief review of the physiology of the parathyroid glands.

1. PHY: Parathyroid Gland
Marona Ysabel G. Julabar

2. PTG
PTG
PTG
PTG
PTG
24-40 mg
3 mm
4 mm
5 mm
Chief PTH

3. PTG
PTH
Bones
Kidneys
prepro
pro
calcitriol
ER
GA

4. Ca2+
PTC PTH
Mg2+
cAMP
↓
↓↓↓hypo-PT-ism

5. Ca2+↑ PO3↓
cAMP
Bone resorption
Renal PO3 reabsorption
Renal Ca2+ reabsorption
Intes. Ca2+ reabsorption
-
+
+
+
phosphaturic effect
↑hydroxyproline exc.
distal tubule
indirectly

6. PTHrP
osteoblast
k. tubules

7. Ca2+ PO3
PTH calcitriol
intestines
circulation
urine
bone

8. Ca2+
anionCHONfree
hypocalcemia hypercalcemia

9. PO3
CHON
free
tissues hyperPO3mia
ATP
nuc.acid
metab.

10. Vit. D calcitriolHYDROXYLATION HYDROXYLATION
Ca2+ PO3
PTH calcitriol
intestines
circulation
urine
bone

11. Vit. D3
UVB
7-dehydrochol.Vit. D2
plants skin liver
25-hydroxyVitD
1,25-hydroxyVitD
kidney
1α-hydroxylasePTHCa2+
PO3
PTH
↓
↓
↑
DBP

12. 1,25-hydroxyVitD
Ca2+ PO3
bone
Intes. Ca2+ absorption
Intes. PO3 absorption
Renal Ca2+ & PO3 reab.
Bone resorption
+
+
+
+
calbindin D-28K

13. VitD r
nuclear ligand dep
gene exp

14. calcitonin
Thyroid parafollicular Ca2+↑
hypercalcemia
Bone resorption
-
-

15. hyperPTism
hypoPTism
hyperCaemia
hypoCaemia
Ca2+↑
PO3↓
PO3↑
Ca2+↓
tetany
PNS
SCC
osteop
.
fx
↑
↓

16. Reference:
• Doc Olalia's pptx