Blood pressure is greatly effected by the volume of blood contained in the closed circulatory system of vertebrates. blood volume is effected by many factors, and regulated primarily by the function of the endocrine and excretory systems. when blood levels lower, the kidney will

The right answer is the kidney will regulate the blood pressure by the renin angiotensin aldosterone system.

The kidney plays a role of selective filtering of the blood. It allows the blood to get rid of its waste. But it also removes water and mineral salts that are in excess.

But the kidney also plays a dynamic role in increasing the pressure, by means of a system called "renin-angiotensin system" which is one of the most powerful natural hypertensives available to the body. Thanks to an enzyme he makes, renin, the kidney will turn a normal blood protein, angiotensinogen, into angiotensin, which causes the vessels in the body to contract and therefore increase blood pressure. This effect is manifested permanently in a disease which is the stenosis of the renal artery, that is to say the permanent narrowing of the caliber of this artery. The kidney, believing that the blood pressure decreases because of this narrowing, will permanently produce renin, which will cause an immediate increase in blood pressure.