Ace Your AQA GCSE Biology Paper 1 2026 – Dive Into the World of Science and Score Big!

As blood moves from arteries to veins, blood pressure decreases. This change occurs primarily due to the structure and function of the blood vessels. Arteries, which carry blood away from the heart, have thick, elastic walls that withstand and maintain high pressure generated by the heart's pumping action. As blood travels through the smaller and more numerous arterioles and capillaries, resistance increases due to the reduced diameter of these vessels, which leads to a drop in pressure.

In the capillaries, where nutrient and gas exchange occurs, blood pressure decreases even further as blood flows into the venous system. Veins have thinner walls and are less muscular than arteries, which means they do not require high pressure to transport blood back to the heart. The lower pressure in veins is sufficient for this function, as the blood is assisted by factors such as muscle contraction and the presence of valves that prevent backflow.

Thus, the overall trend is a continual decrease in blood pressure from arteries to veins, reflecting the differences in vessel structure and the physiological roles they play in the circulatory system.