When the level of sodium ions in the ECF increases,
A) osmoreceptors swell.
B) a person experiences an increased thirst.
C) less ADH is released.
D) there is an increase in the level of aldosterone.
E) there is an decrease in the level of atrial natriuretic peptide.

Question

Quizplus · Accepted Answer

An increase in sodium ions in the ECF triggers the thirst mechanism as a way to increase fluid intake and dilute the concentration of sodium. This is mediated by the hypothalamus and results in the release of antidiuretic hormone (ADH) to conserve water by reducing urine output. However, this does not necessarily result in swelling of osmoreceptors (A) or a decrease in the level of atrial natriuretic peptide (E), which is released by the heart to decrease blood volume and pressure. An increase in sodium ions may also stimulate the renin-angiotensin-aldosterone system, resulting in an increase in aldosterone (D), which promotes sodium retention and potassium excretion in the kidneys. However, this is not the primary compensatory mechanism in response to increased ECF sodium levels.

When the Level of Sodium Ions in the ECF Increases