If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content
Current time:0:00Total duration:4:36

Video transcript

so there are a bunch of organs in our body right all of which are well pretty important to our survival so some of these organs are especially vulnerable to and can be seriously damaged by high blood pressure or hypertension sometimes we call these organs target organs a few example target organs might be like your kidneys so which help regulate salt and water in your body or your brain and your heart all these organs are pretty important right and we definitely don't want them being damaged but how can they be damaged by high blood pressure well blood pressure is the pressure in your blood vessels right and these blood vessels supply the target organs with blood so if your blood vessels get damaged and can't supply as much blood to your target organs well those guys are going to be damaged too right normally your inner wall or your endothelium of your arteries keep blood moving by staying nice and relaxed and resisting what we call clot formation now a clot is like this buildup of coagulated blood which is like kind of like solid blood and this is super important for you to stop blood loss by sort of plugging up an area that's losing blood when you get a cut or are bleeding for some reason now it's not good when these clots start to build up inside of the vessels since they start to make it harder for blood to flow through okay but how can these form well if we're looking at the endothelium this inner lining of the blood vessel our Bloods always going to be cruising over the walls right and when it does this it causes a certain amount of stress from friction along the walls and we call this shear stress now as our pressure in the blood vessels increases the fluid is going to be pushing harder against the walls as it moves by and so your force from friction increases and your shear stress increases to this higher shear stress can start to damage the endothelium or this inner lining of the blood vessels think of like a river flowing along you've got some trees and shrubs and maybe some other stuff maybe like an animal standing in it and they all sort of hang out there without being swept away right but what if all sudden this huge flood comes through it starts to take away the trees and the shrubs and animals with it it's like they're being sheared off the landscape because now that shear stress is way too high in a similar way when you Jam more fluid into these vessels it exerts more pressure radially or outward on the endothelium which makes it want to expand outward with this higher pressure your shear stress is a lot higher - and your blood vessels landscape just like the river is damaged so much so that you start getting these like really tiny microscopic tears in the endothelium and these tears heal but they turn into scar tissue which is fibrotic meaning that it's like this network of connective tissue and when this tissue starts to develop it sort of acts like this net that catches particles like cholesterol fats in platelets as they swim by in the bloodstream when these guys get caught and stuck in the fibrotic net well they stay there and this buildup is called atherosclerosis now this plaque takes up space right and starts to narrow the blood vessels and it also tends to make these vessels stiffer and less flexible and when they harden like this they can't really relax and expand as much as they could before and they get even more prone to injury and more buildup and so as we can see more plaque means less room for blood and so less blood gets through these blood vessels to your target organs like your kidneys your heart and your brain and your blood carries precious oxygen right among other things and without that those target organs don't function as well it can be seriously damaged additionally over time as these vessels get weaker and weaker from higher pressures a bulge might start to form in a weak spot this bulge is also known as an aneurysm and can even burst if it's allowed to get too large which can cause life-threatening internal bleeding these aneurysms can happen anywhere in the body where the arteries become weakened but most commonly that happened in the aorta which is one of your major arteries