Electrolytes

Question 1

Which 4 systems are responsible for calcium and phosphate metabolism?

Answer 1

Renal
GI
Endocrine
Bones

Question 2

What happens to calcium and phosphate in the kidney?

Answer 2

Freely filtered in the glomeruli
Some reabsorbed in renal tubules
That not reabsorbed is excreted in urine

Question 3

How is most calcium ini the body stored?

Answer 3

In the bones as hydroxyapetitie

Question 4

Which 3 molecules are freely permeable across the capillary wall?

Answer 4

Na+, K+, glucose

Question 5

What is not freely permeable across the capillary wall?

Answer 5

Plasma proteins

Question 6

What is Starling’s law of the capillaries?

What does this mean in the body?

Answer 6

Hydrostatic pressure (intracapillary blood pressure) vs oncotic (osmotic pressure exerted by plasma proteins) determines the distribution of extracellular water between vascular and interstitial space.
Hydrostatic pressure is high at arterial end of capillaries, water is pushed out, as water leaves, oncotic pressure in the vessel rises, water sucked back in.
The net flow of fluid outwards is balanced by 'suction' of fluid in the lymphatics.

Question 7

What are the 4 general causes of oedema?

Answer 7

Incr hydrostatic pressure (eg sodium and water retention)
Reduced oncotic pressure (eg nephrotic syndrome with hypoalbuminaemia)
Obstruction to lymphatic flow
Incr permeability of BVs (e.g. inflammation - cytokines)

Question 8

Name 2 colloid fluids

Answer 8

Dextran 70

Gelatin