Final answer:
Increased blood volume would be caused by increased atrial natriuretic factor secretion.
Step-by-step explanation:
Increased blood volume would be caused by increased atrial natriuretic factor secretion. Atrial natriuretic factor (ANF), also known as atrial natriuretic peptide (ANP), is released by the heart when blood volume is high enough to cause extreme stretching of the atrial walls. ANF promotes loss of sodium and water from the kidneys and suppresses the production and release of renin, aldosterone, and antidiuretic hormone (ADH). These actions promote loss of fluid from the body, resulting in a decrease in blood volume and blood pressure.