Calcium and Phosphate balance Flashcards Preview

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Flashcards in Calcium and Phosphate balance Deck (11):
0

Hormones involved in regulating Ca2+

PH, Vit D, CT

1

Effectors in Ca2+ regulation

Bone - Ca storage
GI tract - Ca absorption
Kidney - Ca excretion

2

[Ca2+ ] in blood determined by

Input-output balance
Binding of ionized calcium to plasma proteins

3

role of Ca2+ in body

excitation-contraction coupling in muscle
secretion and release of neurotransmitters
membrane excitability
regulation of enxyme activity
bone formation

4

pH & Ca2+

Increase in blood pH cause release of Ca2+
inc pH = inc bound Ca = dec free Ca = low Ca2+
Decreasing ph in bone matrix cause demineralization and release of Ca2

5

role of phosphate

metabolism
ATP
modulation of enzyme activity
important constituent of bone

7

PTH

Peptide hormone
Secreted by parathyroid cells in response in decreased cell plasma
PTH synth and degradation also increase if blood Ca2+ low
causes increase in VitD3 (increases GI absorption of Ca)
causes increase in Ca reabsorption

8

Vit D3

Sun/Food to Liver to Kidney (made active)
Increases absorption of Ca2+
Release stimulated by inc PTH, dec Phosphate
Synthesized in skin from sun or food intake

9

25 - Vit D3

Formed in liver
Sent to kidney for activation

10

1,25 Vit D3

Active form
Formed in Kidney

11

24,25 Vit D

excess Vit D form (from 1,25 VitD)