An immune response occurs when antibodies, which are proteins in your immune system, are summoned to attack an antigen. When you say you are blood type A, what you are telling people is that the cells in your body make antibodies only to type B antigens.
Best Answer: Blood pressure elevates when the arterioles constrict, which increases the volume carried in the larger arteries, which increases the pressure exerted against the interior walls of those arteries.When vessels constrict, they tighten, and reduce the amount of space inside.ee constrict think choke. Constricting arteries mean the diameter of the hollow part of the arteries where the blood flows is getting smaller. This generally increase blood pressure. When the blood vessel dilates, the diameter increases, lowering blood pressure.
The blood pressure in the arteries will decrease as they move  further away from the heart. The arteries are the vessels which  regulate the blood pressure from the heart.E â¦. Ãª Answered In Blood. pressurencreasing someone's blood level can cause blood pressure to  decrease. The more someone is active the better their blood  pressure better.