Fluid compartments
What percentage of body weight is water?
~60%
What hormone increases water reabsorption in the kidneys?
ADH
A patient drinks a large amount of water. What happens to ECF and ICF?
Both increase, water shifts into ICF
what is the major extracellular cation
Sodium
What electrolyte abnormality is commonly caused by excessive water intake?
Hyponatraemia
Approximately what proportion of total body water is found intracellularly
67%
Which regulatory hormone is released in cases of low blood pressure to preserve fluid volume?
Aldosterone
A patient is given a large amount of isotonic saline. How does this affect ECF and ICF
Only ECF is increased
The major intracellular cation.
Potassium (K⁺)
Which electrolyte imbalance is particularly associated with peaked T waves on an ECG?
Hyperkalemia
What two compartments make up the Extracellular fluid
The plasma and the interstitial fluid.
Which hormone is released by the atria when blood volume is increased?
ANP (atrial natriuretic peptide)
A patient is given 1 litre of hypertonic solution, what happens to ECF and ICF?
ECF increase, ICF decreases
Which protein is the primary contributor to oncotic pressure? is it Extracellular or intracellular?
Albumin - extracellular
A patient has severe diarrhoea. Which electrolyte is commonly lost?
potassium
Which fluid compartment contains the smallest volume of fluid?
The plasma
What detects an increase in plasma osmolality and triggers ADH release?
Hypothalamic osmoreceptors
A patient is involved in an accident and loses 2 litres of blood, what happens to ECF and ICF?
Decrease in ECF, unchanged ICF
Which electrolyte is most important in determining ECF volume?
Sodium
What's the first-line emergency treatment to stabilize the heart in severe hyperkalemia?
IV calcium gluconate
A person has 42 L of total body water. Approximately how much fluid is found in the intracellular fluid, and how much is found in the extracellular fluid?
28 Litres ICF and 14 Litres ECF
ADH and aldosterone can both increase water retention. What is the most important difference between them?
ADH increases water reabsorption while aldosterone increases sodium reabsorption
A patient with heart failure develops peripheral oedema, what has happened to the two major ECF compartments?
Fluid accumulation in the interstitial fluid - plasma normal/slightly decreased
what is the most abundant extracellular anion
Chloride
Which electrolyte imbalance would you expect after excessive aldosterone activity?
Hypokalemia