Blood Vessels and Circulation
Ever wondered why your heart beats so hard during exercise? Your circulatory system needs serious pressure to push blood around your entire body efficiently.
There are three main types of blood vessels: arteries (carry blood away from heart), veins (return blood to heart), and capillaries (tiny vessels for exchange). Arteries have thick, muscular walls and elastic fibres because they handle high-pressure, oxygenated blood straight from your heart.
Capillaries are where the magic happens - they're perfectly designed for exchanging oxygen, food and waste with your body cells. They have ultra-thin walls, exist in huge numbers near tissues, and are so narrow that red blood cells barely squeeze through, giving maximum time for exchange.
Veins are quite different - they have thinner walls (lower pressure), wider spaces inside, and crucially, valves to prevent backflow. Without these valves, blood would pool in your legs!
Quick Fact: Your heart is a muscular pump with four chambers - right atrium, right ventricle, left atrium, and left ventricle - each playing a vital role in circulation.