Let's cram some more for GCSE biology. Here's how to memorize all the blood vessels functions in 55 seconds. The first type are veins which end in IN meaning it takes blood into the heart from the rest of the body. The IN can also be used to write thin as they have thin walls which means the hole in the middle known as a lumen is large and the v at the start can represent valves which prevent the backflow of blood.
This is because blood travels slowly at very low pressures. Next up are arteries which begin with an a meaning they take blood away from the heart. The t T can be written as a rotated cross, meaning its properties are opposites to veins.
They don't have thin walls, their walls are thick with a small lumen, they don't contain valves, and that's because the blood in it doesn't travel at low pressures, it travels at a high pressure. The last type are capillaries, which begin with a C because they connect arteries to veins. The C also stands for cell to explain that their walls are one cell thick, and the P stands for permeable as their walls are permeable to improve the diffusion of substances.