In Forensics we are learning the impactful roles of blood pattern analysis. To do so, we had to research and diagram basic human anatomy. The structure, function, and roles of the human circulatory system. Veins, Capillaries, and Arteries all play important roles in our bodies. Arteries are the largest, they carry blood away from our hearts and to the rest of our bodies. The supplied blood contains water and various nutrients. They also transport oxygenated blood around our bodies. Arteries have very thick walls to help with the high pressure blood. They branch into arterioles, which connect to capillaries. The capillaries are tiny blood vessels that allow oxygen, carbon dioxide, nutrients, and water in and out of our blood streams. Capillaries release waste and other unwanted objects from our blood streams. They have very thin walls to help with the diffusion of waste. The blood is very low pressure, and capillaries connect to arteries and veins. Veins carry deoxygenized blood to our heats. They have thin walls and a wide lumen. The thin walls help to insure that the blood only travels in one direction. Veins branch into smaller vessels called venules. The venules are smaller than veins, but are still bigger than capillaries.