In this chapter you will learn:
1. Importance of water to life
2. Processes involved in transport of material across the cell, diffusion, active
transport and osmosis.
3. Turgor and its importance in plants.
4. Transport of water and salts in plants.
5. Transpiration and factors affecting it.
6. Path of organic material in plants.
7. Open and closed circulatory system of animals and circulatory system of man.
8. Blood groups and Blood diseases.
In all living organisms’ plants and animals, physiological processes are continually taking place in their bodies. In order to sustain life, these processes must be kept going on for which the materials required, must be constantly transported to and from all parts of the body right down to the individual cells. Materials are also to be transported between the cell organism and external environment. In unicellular and simple multicultural organisms, the distribution of materials can be adequately brought about by diffusion and streaming movements of the cytoplasm (fig. 12.1).
However, the evolution of more and more complex body structures recessitated the development of proper transport system, and more complex the organisms are, the more elaborate transport system they have. The complexity of transport system is related to the size and the metabolic rate of the living organism.
The materials to be transported are taken close to tissues be the transport system so that diffusion can occur efficiently into the cells. The primary function of the transport system is to maintain a link between all cells of the body and the external environment. It transports the nutrients to the points where they are to be used, facilitates the elimination of metabolic wastes of each cell and transports surplus substances to the specialized storage tissues or to out side their bodies.