What is meant by high and low pressure in the blood? Watch

jonjoshelvey21
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for example in my textbook it describes adaptations of the arteries to maintain a high pressure in the blood, but what does it actually mean by a high pressure and what's the importance of this?
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Relentas
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(Original post by jonjoshelvey21)
for example in my textbook it describes adaptations of the arteries to maintain a high pressure in the blood, but what does it actually mean by a high pressure and what's the importance of this?
(Not a medical student)
High pressure is when theres enough blood to be easily pumped round your body by your heart, maintaining a high pressure is important as if you had really really low pressure then you'd be at risk of fainting and I guess possibly death due to your brain not getting enough oxygen, your blood would barely be able to pump to your brain.

Your body adapts in order to keep your blood pressure high by constricting vanes and I assume arteries, this basically offers less room for the same amount of blood and so keeps them at the same pressure, think of a balloon, you blow a ton of air into it and then squeeze it, the air has less places to go and so bounces and hits the edge of the balloon more increasing the pressure - thats also why they can pop (can also happen with vanes too, from online: Untreated high blood pressure is a major preventable cause of brain hemorrhages. Aneurysm . This is a weakening in a blood vessel wall that swells. It can burst and bleed into the brain, leading to a stroke.). Low pressure is when you only blow a tiny bit of air into the balloon, so little that its still a bit "flaccid", you then can squeeze the balloon so that theres more pressure.
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macpatgh-Sheldon
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Good answer by Ralentas, just to add some other points:

The initial blood pressure generated by the heartbeat (called the systolic blood pressure - normal around 120mm Hg in a young adult) is deendent on the diameter of the so-called resistance arterioles. These vessels have an elastic layer in their walls, which stretches when the heart beats, then rebounds [rather like a pulled rubber band when you let one end go] producing a second smaller peak in blood pressure called diastolic blood pressure (normal about 80 mm Hg).

The human body has several mechanisms of controlling and maintaining blood pressure, including control of sodium levels by the kidneys (you might know that doctors recommend people with high blood pressure to limit salt intake) as well as various chemicals, some working via nerves, that can change the diameter of arterioles, thus modulating the resistance posed against blood flow and controlling blood pressure.

M (ex-medic)
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