Calcium Regulation.

1. Calcium Metabolism 🧪
Bilin Benoy
Mbbs 2021

2. 1.What is the normal Serum Calcium level?
2.Enumerate the hormones of calcium metabolism.
3.Role of hormones in maintaining calcium homeostasis.

3. FUNCTIONS OF CALCIUM
1.Maintenance of Action Potential in Cardiac & Smooth Muscles.
2.Excitation Contraction Coupling during muscle contractions.
3. Controls Cell Division .
4.Mineralization of Bones.
5.Blood Coagulation.
6.GI Motility.
7. 2° Messengers for hormones Actions.

4. DISTRIBUTION OF CALCIUM IN BODY
🌝 1 - 1.5 kg of calcium present in body
•Present in Bones & Teeth. (99%)
1% - Readily Exchangeable
99% -Mobilised through action of PTH

5. DISTRIBUTION OF CALCIUM IN
BODY
Diffusible Calcium
• Ionised Ca² - 50%
• Complexed to
Bicarbonates,Citrate- 10%
• CALCIUM IN PLASMA
Non Diffusible Calcium
• Bound with Albumin -
40%

6. 1) Serum Calcium Level
9-11 mg / dl

7. 2) HORMONES OF CALCIUM
METABOLISM
•Parathormone
•Calcitonin
•Other Hormones –Glucocorticoids, GH, Estrogen
,Testosterone

8. a) PARATHYROID HORMONE
• Parathyroid Gland →Oxyphil cells
→Chief cells - secrete Parathormone.
PTH increases plasma calcium level by:
• Resorption of calcium from bones.
• Resorption of calcium from renal tubules
• Absorption of calcium from GI tract

9. a.1) Action of Parathormone
• Bones - Osteoclastic activity → Ca²+ Ions are relased into the plasma.
• Kidney - ↑ Resorption of Ca²+ from distal tubules & collecting tubules.
• Intestine - Increases absorption of Ca2+
- Activates Vit D.

10. Activation of Vitamin D

11. Actions of VitD

12. b) CALCITONIN
• Produced by - parafollicular C Cells of Thyroid Gland.
• Calcitonin - Decrease plasma Calcium Level.

13. b.1) ACTION OF CALCITONIN
• Bones ;
•Decreases Osteoclastic Activity ,
•Inhibits development of new osteoclast in bones
•Inhibits bone resorption
•Facilitates the deposition of calcium on bones.
• Kidneys -
•Decreases Calcium resorption in kidneys

14. PARATHORMONE CALCITONIN

15. c) OTHER HORMONES
• Glucocorticoids - ↓ plasma calcium by inhibiting osteoclastic activity &
↓absorption from intestine.
• Growth Hormone - Stimulate bone formation /osteoblastic activity.
• Insulin – Promotes Bone Formation
• Estrogen – Inhibits osteoclastic activity → preventing osteoporosis.
• Testosterone - Promotes Bone development.

16. Thank You