Explain how the structures of blood vessels are related to their functions. (Include as much detail as possible.)
Capillaries are very thin (only made of a single layer of endothelium) therefore there is a short diffusion pathway. this makes diffusion of oxygen and glucose into the capillary and carbon dioxide out of the capillary quicker. The diameter of a capillary is small so only one red blood cell can fit through at a time maintaining a concentration gradient for quick diffusion. There are many capillaries so the blood pressure is low and they spread out so a respiring tissue is only ever about 1mm away from a capillary.
Arteries have muscular walls to allow vasomotor control (vasodilation and vasoconstriction) so the organism can maintain a constant body temperature. It has thick walls so it can withstand high pressures when blood is forced out of the aorta.
Veins have valves to stop a backwash of blood, it also has a short diffusion pathway.
How can a mutation cause cancer to develop?