Which of the following situations would be expected to cause an increase in ADH secretion by the posterior pituitary gland?
A)A 5% decrease in arterial blood pressure
B)A 5% increase in arterial blood pressure
C)A 1% decrease in plasma osmolality
D)A 1% increase in plasma osmolality

Question

Quizplus · Accepted Answer

ADH secretion is primarily regulated by changes in plasma osmolality. An increase in plasma osmolality of just 1% is enough to trigger ADH secretion to promote water reabsorption in the kidneys and decrease water loss in urine. Decreases in arterial blood pressure (Choice A) may trigger the renin-angiotensin-aldosterone system to increase water reabsorption in the kidneys, but this would not affect ADH secretion directly. Similarly, an increase in arterial blood pressure (Choice B) would not directly affect ADH secretion. A decrease in plasma osmolality (Choice C) would actually inhibit ADH secretion, as there would be no need to conserve water in the body when there is excess available.

Which of the Following Situations Would Be Expected to Cause