BIOD 331 PATHOPHYSIOLOGY EXAM 3
TESTED QUESTIONS AND COMPLETE
SOLUTIONS
◉ Why is sodium important?
Answer: It is the major extracellular cation and regulates
extracellular fluid volume and water balance.
◉ Key rule about sodium and water
Answer: Water follows sodium.
◉ Functions of sodium
Answer: Neuromuscular irritability, acid-base balance, membrane
transport, and cellular reactions.
◉ Aldosterone
Answer: Hormone from the adrenal cortex that increases sodium
and water reabsorption and increases potassium and hydrogen
excretion.
◉ When is aldosterone released?
Answer: When sodium is low, potassium is high, or renal
perfusion is low.
,◉ Overall effect of aldosterone
Answer: Retains sodium and water; excretes potassium and
hydrogen.
◉ Renin-angiotensin-aldosterone system (RAAS)
Answer: Hormonal system activated by low renal perfusion, low
blood pressure, or low sodium to restore perfusion and volume.
◉ Renin
Answer: Enzyme released by the kidney that begins the RAAS
cascade.
◉ Angiotensin II actions
Answer: Stimulates aldosterone release, increases thirst,
promotes ADH release, and causes vasoconstriction.
◉ Net effect of RAAS
Answer: Raises sodium, water, blood pressure, and kidney
perfusion.
◉ Natriuretic peptides
Answer: ANP and BNP; hormones that oppose RAAS and promote
sodium and water excretion.
◉ ANP
, Answer: Atrial natriuretic peptide; released from atria.
◉ BNP
Answer: B-type natriuretic peptide; released from ventricles.
◉ What do natriuretic peptides do?
Answer: Decrease blood pressure and increase sodium and water
excretion.
◉ Why are BNP and ANP elevated in heart failure?
Answer: Because chamber stretch from fluid overload stimulates
their release.
◉ Chloride
Answer: Major extracellular anion that helps maintain
electroneutrality and usually follows sodium.
◉ Relationship between sodium and chloride
Answer: They generally change in the same direction.
◉ Relationship between chloride and bicarbonate
Answer: They generally change inversely.
◉ If sodium goes up, what happens to chloride?
TESTED QUESTIONS AND COMPLETE
SOLUTIONS
◉ Why is sodium important?
Answer: It is the major extracellular cation and regulates
extracellular fluid volume and water balance.
◉ Key rule about sodium and water
Answer: Water follows sodium.
◉ Functions of sodium
Answer: Neuromuscular irritability, acid-base balance, membrane
transport, and cellular reactions.
◉ Aldosterone
Answer: Hormone from the adrenal cortex that increases sodium
and water reabsorption and increases potassium and hydrogen
excretion.
◉ When is aldosterone released?
Answer: When sodium is low, potassium is high, or renal
perfusion is low.
,◉ Overall effect of aldosterone
Answer: Retains sodium and water; excretes potassium and
hydrogen.
◉ Renin-angiotensin-aldosterone system (RAAS)
Answer: Hormonal system activated by low renal perfusion, low
blood pressure, or low sodium to restore perfusion and volume.
◉ Renin
Answer: Enzyme released by the kidney that begins the RAAS
cascade.
◉ Angiotensin II actions
Answer: Stimulates aldosterone release, increases thirst,
promotes ADH release, and causes vasoconstriction.
◉ Net effect of RAAS
Answer: Raises sodium, water, blood pressure, and kidney
perfusion.
◉ Natriuretic peptides
Answer: ANP and BNP; hormones that oppose RAAS and promote
sodium and water excretion.
◉ ANP
, Answer: Atrial natriuretic peptide; released from atria.
◉ BNP
Answer: B-type natriuretic peptide; released from ventricles.
◉ What do natriuretic peptides do?
Answer: Decrease blood pressure and increase sodium and water
excretion.
◉ Why are BNP and ANP elevated in heart failure?
Answer: Because chamber stretch from fluid overload stimulates
their release.
◉ Chloride
Answer: Major extracellular anion that helps maintain
electroneutrality and usually follows sodium.
◉ Relationship between sodium and chloride
Answer: They generally change in the same direction.
◉ Relationship between chloride and bicarbonate
Answer: They generally change inversely.
◉ If sodium goes up, what happens to chloride?
