Final answer:
The hormone secreted by the adrenal cortex in response to low dietary salt intake is aldosterone, which helps regulate the body's sodium and water balance to maintain blood pressure.
Step-by-step explanation:
The adrenal cortex secretes the hormone aldosterone in response to low dietary salt intake. Aldosterone is important for regulating electrolyte and water balance in the body. When dietary salt intake is low, the adrenal cortex increases the secretion of aldosterone to promote reabsorption of sodium ions in the kidney tubules, which helps to increase blood volume and maintain blood pressure.
Aldosterone achieves this by enhancing the rate of sodium ion reabsorption and increasing the secretion of potassium and/or hydrogen ions by the renal tubules. Also known as the "salt-retaining hormone," aldosterone promotes water retention, which in turn reduces urine output, helping to conserve sodium and water in the body.