Red blood cell Carry oxygen. Contain haemoglobin (rich in iron) to carry oxygen. Biconcave shape to provide a large surface area for the diffusion of oxygen. No nucleus to provide more space for ...

blood a pump (the heart) to push the blood around the body a system of tubes to contain the blood (arteries, veins and capillaries) The blood is the transport medium – it carries substances to ...

Circulatory system is the first organ system to become functional during development. Development of heart: On each side of embryo, an aorta forms ventrally and swings dorsally. The paired aortae in ...