Calcium balance
This presentation is the property of its rightful owner.
Sponsored Links
1 / 7

Diet PowerPoint PPT Presentation


  • 68 Views
  • Uploaded on
  • Presentation posted in: General

Calcium balance. Diet. 1.000 mg. Absorbed 500 mg. Formation 280 mg. Calcium pool. Bone. intestine. reabsorption 280 mg. Secreted 325 mg. Stool. Reabsorbed 9.825 mg. Filtered 10.000 mg. 825 mg. Kidney. Urine. 175 mg. hormones regulating Ca 2+ balance.

Download Presentation

Diet

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Diet

Calcium balance

Diet

1.000 mg

Absorbed

500 mg

Formation

280 mg

Calcium

pool

Bone

intestine

reabsorption

280 mg

Secreted

325 mg

Stool

Reabsorbed

9.825 mg

Filtered

10.000 mg

825 mg

Kidney

Urine

175 mg


Diet

hormones regulating Ca2+ balance

Parathyroid hormone ( = PTH ) produced in parathyroid gland)

• increases Ca2+ reabsorption in the kidney

Vitamin D ( = 1,25 - Dihydroxycholecalciferol ) generated from Cholecalciferol in the kidney

● increases Ca2+- reabsorption in kidney and intestinum

● deposition of Ca2+ in the newly formed bone

Calcitonin ( = Thyreocalcitonin ) from C cells of thyroid gland

● stimulate Ca2+ excretion in the kidney


Diet

Skin (+ UV)

Liver:

Dehydro -Cholesterin

Cholecalciferol

Kidney:

1,25-(OH)2-Cholecalciferol

25-OH-Cholecalciferol

= Vitamin D

Genesis of D -hormones

Liver:


Diet

A: Ca++ Reabsorption

8%

70%

1%

20%

II. other influential factors:

Alkalosis: increases the reabsorption in distal

tubule and acidosis does the opposite

1%

Influential factors on Ca++ handling along a Nephron

B: Regulation of Ca++-Reabsorption

I. hormone:

Parathormone: increases overall the Ca++ reabsorption,

but strongly in the Henle`s loop and in distal tubule.

PTH lowers the reabsorption of NaCl and Water and thus of Ca++ in proximal tubule. The overall result is a net

Increase in Ca++reabsorption

Calcitonin: inhibits Ca++ reabsorption in Henle`s

loop and in distal tubule

Calcitriol: increases Ca++ reabsorption in distal

tubule

increased Plasma phosphate:induces the release

of PTH and thus elevates Ca++ reabsorption

ECV reduction:increases Ca++ reabsorption and

ECV entlargement reduces Ca++ reabsorption


Diet

Tubule

lumen

Interstitial

space

Ca2+

3 Na+

2 Ca2+

Ca2+

2

Ca2+-sensing receptor lowers levels of cAMP, which otherwise stimulates Na+/K+/Cl- Cotransporter.

Arachidonic acid

P450

20-HETE

Na+

K+

2 Cl-

Ca2+

K+

Ca2+

Receptor

Ca2+

Ca2+

Paracellular Diffusion


Diet

Chief cell of

parathyroid

_

_

+

+

+

+

+

+

+

+

+

+

PTH

_

Ca2+ absorption

Ca2+ reabsorption

Plasma Ca2+

8,5-10,6 mg/dl

Bone

Intestine

Tubule Ca2+ reabsorption

Kidney

Tubule Phosphate reabsorption

Conversion of

25-OH-Vitamin D

Cu

1,25-(OH)2-Vitamin D


Diet

_

_

+

+

+

+

+

+

+

+

+

+

_

Chief cell of

parathyroid

PTH

Ca2+ absorption

Ca2+ reabsorption

Plasma Ca2+

8,5-10,6 mg/dl

Plasma Phosphate

Bone

Intestine

Phosphate

Phosphate

Tubule Ca2+ reabesorption

kidney

Tubule Phosphate reabsorption

Conversion of

25-OH-Vitamin D

to

1,25-(OH)2-Vitamin D


  • Login