Final answer:
The three hormones regulating blood volume are ADH, aldosterone, and ANH, with the kidneys and adrenal cortex working together to converse water and sodium to increase blood volume.
Step-by-step explanation:
The mechanisms of the three hormones that work together to regulate blood volume are antidiuretic hormone (ADH), aldosterone, and atrial natriuretic hormone (ANH). ADH is secreted by the posterior pituitary and it promotes water reabsorption in the kidneys, leading to an increase in blood volume. Aldosterone, produced by the adrenal cortex, enhances sodium and water retention, also contributing to an increased blood volume. Lastly, ANH or atrial natriuretic peptide, which is secreted by the heart's atria in response to stretching due to increased blood volume, acts to reduce blood volume by opposing the actions of aldosterone and leading to the excretion of sodium and water.
The kidneys and the adrenal cortex play crucial roles in these mechanisms. Through the renin-angiotensin-aldosterone system, the adrenal cortex releases aldosterone, which increases the reabsorption of sodium and water in the kidneys, thereby increasing blood volume. Simultaneously, the kidneys respond to the release of ADH by conserving water and reducing urine output, further helping to restore blood volume after it's been depleted due to events like hemorrhage or dehydration.