Download MBBS Physiology Presentations 13 Hormonal Control of Calcium And Phosphate Metabolism Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Physiology 13 Hormonal Control of Calcium And Phosphate Metabolism PPT-Powerpoint Presentations and lecture notes

Hormonal control of

calcium & phosphate

metabolism

Introduction

Calcium is an intracellular signaling

molecule

1100 gms of calcium is present in the

body

99% is in the skeleton
Plasma calcium = 10 mg/dl; is partly

bound to proteins and partly diffusible

Phosphorus

Found in AT P, c AMP, 2,3-BPG,

proteins

Total body phosphorus ? 500-800 gm
85-90 % is in the bones
Plasma phosphorus ? 12 mg/dl
2/3 of it is organic form and rest in

inorganic form- phosphate, hydrogen

phosphate and dihydrogen phosphate
Vitamin D

Increases calcium absorption from the

intestine

Increases phosphate absorption

through intestine

Decreases renal excretion of calcium

and phosphate
1,25- dihydroxycholecalciferol is also

formed in placenta, keratinocytes in

skin and macrophages

Levels are increased in pregnancy

Parathyroid hormone

Increases calcium and phosphate

absorption from the intestine

Increases calcium and phosphate

absorption from bones

Decreases renal excretion of calcium

and increases renal phosphate

excretion
Calcitonin

It is proportional to plasma calcium

levels

-adrenergic agonists, dopamine and

estrogens stimulate calcitonin

secretion

Gastrin, CCK, glucagon and secretin

also stimulate

Plasma calcitonin levels are high in

Zollinger-Ellison syndrome and

pernicious anemia

Calcitonin lowers plasma calcium and

phosphate levels

Inhibits bone resorption
Vitamin D Deficiency diseases

Rickets
osteomalacia

Osteopetrosis:
Increased bone density

Osteoporosis:
Decreased bone density
Fractures common