How do arteries affect blood pressure?
Arteries carry blood away from the heart, and atherosclerosis can narrow arteries, increasing blood pressure.
Arteries tend to be the blood vessel with the thickest walls since they carry blood away from the heart. Since the blood coming from the heart has just been pumped and needs to have a high enough pressure to reach the rest of the body, blood in the arteries constantly pushing against the artery walls. Blood pressure, among other things, measures how hard blood pushes against the artery wall, so artherosclerosis shrinks the artery and increases blood pressure. Atherosclerosis is the buildup of fats and cholesterol along the artery wall. This build-up of arterial plaque clogs the artery and results in higher blood pressure.
Imagine you and a crowd of other students are all moving in one direction through a narrow hallway. While you may have a little breathing room while doing so, imagine the size of the hallway is shrunk in half. It becomes much harder to move through the hallway the smaller it gets, doesn't it?
Similarly, plaque buildup in arteries shrinks the size of the arteries. Since the blood is now moving through a narrower space, it is exerting more force against the artery walls. Recall blood pressure is essentially the force blood exerts against arterial walls. When the artery becomes too narrow for the blood cells to move through it, the blood pushes out against the artery walls, leading to high blood pressure.
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