Since aldosterone promotes Na+ retention and K+ loss, one might predict (on the basis of negative feedback) that aldosterone secretion would be increased when there was a low Na+ or a high K+ concentration in the blood. This indeed is the case. A rise in blood K+ directly stimulates the secretion of aldosterone from the adrenal cortex. A decrease in plasma Na+ concentration, if it causes a fall in blood volume, also promotes aldosterone secretion. However, the stimulatory effect of a fall in blood volume on aldosterone secretion is indirect, as described in the next section.
Was this article helpful?
This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.