-
Blood flow in the system causes changes in pressure throughout the body. A similar example is water pressure changing in a water hose. When you turn the spigot on, water pressure in the hose increases and water flows out the other end of the hose. If the nozzle is closed at the far end, there is no way for the water to flow out and the pressure increases in the hose. On the other hand, if you open the nozzle of the hose, the pressure is very high at first as the water spurts out, but as the flow through the hose equalizes, the pressure decreases. If you turn off the spigot, the pressure decreases so much that water stops flowing through the hose.
The arteries have muscles in their walls that dilate and constrict to maintain even blood pressure, even when there is increased cardiac output or a leak in the system. When there is a leak in the system, your body detects this leak and patches this leak with platelets. Platelets act as a plug to keep people from bleeding to death, by forming a clot around the leak. - If the heart pushes out blood with a great force, the arteries dilate to lower the blood pressure to keep from damaging the organs. If the heart pumps out a lot of blood, the blood pressure increases, if the heart pumps out a little blood, the blood pressure decreases. Position plays another role in lowering blood pressure. When you sit or stand suddenly, your blood pressure drops suddenly, because it takes more pressure to go uphill than it does to go downhill, and the arterial system has to have time to adjust to this sudden drop in pressure. Your body can also lower blood pressure when you are lying down, especially during procedures such as a colon test or maybe a pap smear, because the nervous system is being stimulated, causing a drop in blood pressure.
- If a major artery is cut, the blood pressure will drop rapidly, because of the huge leak in the system. Alcohol is considered a vasodilator (widening of a blood vessel.) The wider the blood vessel, the lower the blood pressure will be. The thinner the blood vessel, the higher the blood pressure will be. Blood pressure is like water flowing down a river, it is fastest when there are no currents or turbulences. Turbulence in the way of flowing blood will slow down the pressure considerably. When your body temperature rises, this causes the blood vessels to dilate, thereby lowering blood pressure. When the volume of blood decreases, blood pressure decreases. This depends on the cardiac output (volume of blood being pumped by the heart in one minute). Excessive sweating causes reduced blood volume, lowering blood pressure. This is due to too much water being lost in the body. If you are experiencing excessive thirst, your blood pressure is probably lower than normal.
