Session 6 Flashcards
Two types of diabetes insipidous?
Neurogenic (brain)-inadequate absorption of water at collecting duct, as ADH is too low.
Nephrogenic (kidney)-acquired insensitivity of kidney to ADH, water is I adequately absorbed from CD. Give ADH injections.
How does ADH cause thirst?
Roles of ADH?
Activation of the V1 receptor in VSM cause vasoconstriction triggering thirst response in hypothalamus.
Reabsorption in CD, thirst, and urea reabsorption.
Dispogenic diabetes?
Defect or damage to hypothalamus causing malfunction to thirst mechanism, so individual is excessively thirsty regardless of fluid status. So high fluid intake suppressing vasopressin increasing urine output.
How does the counter current system cause concentration urine?
In the collecting duct as you move down the interstitial concentration increases allowing the conc of the collecting duct to increases as you move down as water can keep moving out. This increasing interstitial concentration is only present due to the counter current created by ions moving out of the ascending limb in the LOH.
Does ADH cause thirst?
Maybe long term with the vasoconstriction but really it’s just the osmoreceptors stimulated by the increase in osmolality
Serum potassium?
Intracellular conc?
If pathology how can you increase k excretion?
3.5-5.5 mmol
140 mmol
Dialysis or increase urinary excretion
%of fluids v solids in women?
Symptoms of hyper/o/kalaemia?
Where is 2/3 of k absorbed from the nephron?
Where is the rest?
45% solids and 55% fluids
Weakness,muscle cramps, chest pain
Proximal convoluted tubule
Ascending LOH and DCT
What stimulates potassium secretion into the lumen for excretion?
Normal k conc in urine?
Furosemide?
Aldosterone
60-80mmol/l
Diuretic that enhances k loss in urine as stops k being reabsorbed in ascending LOH
Causes of hyperkalaemia?
Treatment?
Aldosterone deficiency, acidosis(h into cells replacing k) and blood transfusion.
Insulin/salbutamol as shifts k into cells.
Furosemide enhance k loss in urine.
Causes of hypokalaemia?
Treat?
K into cells due to insulin
Decreasd intake
Renal losses due to diuretics
K replacement (bananas) IV saline and 40 mmol of k
When is k at its highest and NA at its lowest?
What happens to cells in hypernatraemia?
Hypo
Intracellular
Cell shrinkage/confusion/seizures
Cell swelling,cerebral oedema, headache
4 common IV fluids and constituents?
5% Dextrose- 50g/l glucose and 252 osmoles
4% Dextrose 0.18% saline- 40g/l, 262 osmoles and 30 NA and CL.
Saline- 308 osmoles and 154 NA and CL.
Hartman should solution- 280 osmoles and 131 NA and CL.
Daily mai tame century for a man of CL NA and k
1mmol/d
