What is the strongest blood pressure regulator?

What is the function of the Antidiuretic hormone (=ADH)?

Atrial natriuretic peptide (=ANP) is a hormone that decreases the blood pressure by increasing the loss of sodium by the kidneys which in turn reduces the blood volume. Where is this ANP actually secreted?

An important part of the renin-angiotensin-aldosterone blood regulation system is the conversion of angiotensin I into angiotensin II. Where does this conversion take place?