BTEC Applied Science Unit 1 Biology Blood Vessels. Now there's three types of blood vessel that we need to know arteries veins and capillaries. Arteries, nearly all arteries take blood away from the heart so the blood in arteries is high pressure blood and it contains lots of oxygen in the hemoglobin. Arteries take blood away from the heart apart from the artery which goes to the lungs. Veins take blood to the heart, so they carry blood from the body and that goes to the heart.
So this blood contains less oxygen, so it's not bright red and it's at a lower pressure. as well. So veins take blood to the heart.
Capillaries are the tiny blood vessels which take blood to and from your cells, for example to and from your muscles. So they are tiny blood vessels. Arteries and veins.
Now the structure of arteries and veins. Now both have an outer layer of connective and elastic tissue. So this outer layer of tissue, it's thicker. in veins because veins are more likely to collapse because the blood pressure is lower in veins. So they have an outer layer of connective and elastic tissue.
This is arteries and veins. of them have a layer of smooth muscle tissue they have a layer of muscle tissue this is thicker in arteries because arteries can actually help to pump the blood when you're feeling somebody's pulse you're feeling the arteries helping to pump the blood around your body to keep up the blood pressure and then all three have an endothelial layer on the inside okay So, well, the capillaries are just basically an endothelial layer and it's on the inside in arteries and veins. A disease we need to know, atherosclerosis.
So what can happen? Fatty deposits. Now, these fatty deposits are called an atheroma and they can block an artery.
and they can lead to a blood clot actually blocking the artery. And the blood clot is called a thrombosis. So fatty deposits and atheroma can block an artery or lead to a blood clot.
blocking it called a thrombosis and this can cause all kinds of problems it can cause coronary disease which is perhaps a heart attack and it can cause strokes as well if it's the blood going to your brain and if one of those arteries gets blocked you could have a stroke So what causes it? Well, the endothelial tissue, which is on the inside, remember, is damaged. It could be damaged by smoking or by high blood pressure.
And so what happens is that a type of cholesterol called LDL cholesterol accumulates in the wall. And this causes the wall to become inflamed. It causes inflammation. So why? blood cells move in to try and fix the problem then you get a buildup of all kinds of stuff you've got the LDL cholesterol the white blood cells and calcium salts and fibers and it forms plaque and plaque can be like a crusty stuff plaque formation and this is your atheroma okay which blocks the cell sorry blocks the artery the atheroma so the art artery becomes narrow and less elastic, blood flow is restricted and there's a much bigger risk of blood clotting.
So what happens is that your blood pressure rises and so the endothelial tissue gets damaged even more. So there's a vicious circle going on here. Cigarettes again. Cigarette smoke contains lots and lots of toxic nasty chemicals.
I've already talked about the damage that it does to your lungs and your breathing passages but these chemicals they make your blood thicker and this thick blood causes fatty deposits to build up and smoking also raises blood pressure and heart rate and this can damage the endothelium Sketch and describe the structure of the three types of blood vessel. What is atherosclerosis? Describe how it develops. What major diseases can it cause?
And describe how smoking can lead to atherosclerosis.