Transport In Animals

 Simple multicellular animals do not have transport systems. Such animals are small and have a large S.A/V ratio, so diffusion is sufficient to meet their needs. Other animals have a mass flow system to bring about transport and distribution of materials. The main materials that are transported in Animals are

 • Digested food, water and other nutrients;

 • Oxygen;

 • Excretory products such as carbon dioxide, urea and water; and

 • Hormones.

     All materials are transported with an animal in form of an aqueous solution. Transport media are, therefore, fluids. In simple animals, cytoplasm and water acts s transport media. In most animals, however , blood is the main medium of transport. Intercellular fluid and lymph are part of blood and play an important role in the transport of materials to the individual body cells.