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.
But if your blood pressure drops suddenly or causes symptoms like dizziness or fainting, it is too low. It can cause shock. Shock can be dangerous if it is not treated right away. Blood pressure is a measure of how hard the blood pushes against the walls of your arteries as it moves through your body.omeone with a systolic pressure of 120 and a diastolic pressure of 80 has a blood pressure of 120/80, or 120 over 80.. Normal blood pressure is lower than 120/80. Low blood pressure does not have a specific number where it is too low.