Calcium and Phosphate balance

Question 0

Effectors in Ca2+ regulation

Answer 0

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

Question 1

Hormones involved in regulating Ca2+

Answer 1

PH, Vit D, CT

Question 2

[Ca2+ ] in blood determined by

Answer 2

Input-output balance

Binding of ionized calcium to plasma proteins

Question 3

role of Ca2+ in body

Answer 3

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

Question 4

pH & Ca2+

Answer 4

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

Question 5

role of phosphate

Answer 5

metabolism
ATP
modulation of enzyme activity
important constituent of bone

Question 7

PTH

Answer 7

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

Question 8

Vit D3

Answer 8

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

Question 9

25 - Vit D3

Answer 9

Formed in liver

Sent to kidney for activation

Question 10

1,25 Vit D3

Answer 10

Active form

Formed in Kidney

Question 11

24,25 Vit D

Answer 11

excess Vit D form (from 1,25 VitD)