2.5 Extracellular calcium and phosphate homeostasis Flashcards Preview

Block 6 > 2.5 Extracellular calcium and phosphate homeostasis > Flashcards

Flashcards in 2.5 Extracellular calcium and phosphate homeostasis Deck (13)
1

How is extracellular calcium stored and when can it be filtered?

It can either be bound (albumin and globulin) or free. It is the free form that can be filtered

2

What is the transporters involved in Ca outflow?

CA-ATPase and Na/Ca exchanger

3

Describe the transcellular pathway of Ca

Ca comes in thrugh luminal channel and binds to Calbindin (binding protein). This is transported through the cell and will leave as unbound Ca via the CA-ATPase and NA/Ca exchanger

4

What can speed up the process of resorption of Ca?

Calcitriol - increases protein expression of calbindin

5

Where is Ca excreted?

Kidney

6

What is the rate limiting factor in Ca resortion?

The Na/Ca exchanger and CaATPase

7

What is the short and long term regulators of calcium?

Short: pH
Long: Ca sensing on cell membrane and hormonal feedback loops

8

What happens to Ca in alkalosis and acidosis?

Increases in acidosis, decreases in alkalosis

9

What is the role of calcium sensor proteins and give an example

They bind to a host of adaptor proteins leading to transduction pathways and regulated processes such as synaptic plasticity, memory formation, gene expression

Neuronal calcium sensor-1

10

What is the role of calcitonin?

Released in proportion to Ca and acts to inhibit osteoclast activity in bone, converts active vitamin D into inactive in the kidney causing decreased Ca absorption

11

What effect does PTH have on Ca and phosphate?

increase calcium, decrease phosphate

12

what effect does calcitriol have on Ca and phosphate?

Increase clacium and increase phosphate (increased uptake and renal reabsorption)

13

What effect does calcitonin have on Ca and phosphate?

Decreases both