Sodium

what is the chief electrolyte in extracellular fluid?

sodium

normal range for sodium?

135-145 mEq/L

where is sodium mostly found?

extracellular fluid (ECF)

how does sodium affect water movement?

WATER FOLLOWS SODIUM

• sodium loss or gain is accompanied by a loss or gain of water

main jobs of sodium?

• regulates extracellular fluid volume and osmolality

• enables muscle contraction

• transmits nerve impulses

• regulates acid base balance

how is sodium moved across cell membranes?

via the sodium-potassium pump moving sodium out of cells

what regulates sodium balance?

• kidneys regulate excretion and reabsorption

• RAAS increases retention via aldosterone

common dietary sources of sodium?

• table salt

• processed foods

• restaurant and fast foods

common routes of sodium loss?

• GI tract

• kidneys (urine)

• skin (sweat)

recommended adult sodium intake?

about 1,500-2,000 mg/day

what foods drive excess sodium intake?

processed foods; fast food meals

how do sodium and potassium relate?

often move in opposite directions; high sodium tends to pair with lower potassium and vice versa

why does sodium matter for neuro and muscles?

sodium shifts change neuron firing and muscle contraction so imbalances can cause neurological changes and muscle dysfunction

how is sodium transport linked to fluid balance?

moving sodium changes osmolality and pulls water with it