Sodium (The First Macromineral) Flashcards
What are macrominerals?
The daily requirement is > 100 mg
Seven principal elements: Ca, P, Mg, Na, K, Cl & S
What are the functions of sodium?
Principal cation in extracellular fluids
Maintain fluid balance
Maintain membrane potential of most cells
Generate action potential in excitable cells
RDA of sodium
2300 mg/day
Which foods have the most sodium?
Processed foods such as bread, chesse and salted butter
What are the outputs of sodium?
Feces, sweat and urine
How is reabsorption of sodium regulated?
Regulated by aldosterone which in turn is under the control of the renin-angiotensin system
Ion components of ECF
Mainly Sodium,
Also contains smaller concentrations of Potassium, Calcium, Magnesium, Chloride and Bicarbonate
Ion components of ICF
Mainly potassium
Small concentrations of Calcium, Magnesium, organic phosphate
Sodium concentration at which hyponatremia (sodium depletion) is defined?
Decrease in serum sodium concentration < 136 mEq/L
When does hyponatremia occur?
Excessive sweating
Diarrhea
Diuretics or osmotic diuresis
Adrenal insufficiency (e.g. Addison’s disease)
What is Addison’s disease?
Reduced production of cortisol
May also include impaired production of aldosterone, which regulates sodium conservation, potassium secretion, and water retention
What are the symptoms of hyponatremia?
Dry mouth and tongue
Loose skin
Sunken eyes
Weak pulse
Sodium concentration at which hypernatremia (sodium excess) is defined?
Exceeding 145 mmol/L
When does hypernatremia occur?
Patients with decreased cardiac output and inability to excrete sodium
Nephrotic syndrome due to increased water retention because of reduced plasma oncotic pressure
What are the effects of hypernatremia?
Too much sodium is linked to negative health consequences such as hypertension and cardiovascular disease
