Chapter Overview Transport in Mammals

Learning Objectives By the end of the lesson, you should be able to: *Describe the circulatory system as a system of tubes with a pump and valves to ensure one-way flow of blood. *Describe the double circulation in terms of a low pressure circulation to the lungs and a high pressure circulation to the body tissues and relate these differences to the different functions of the two circuits. Describe the structure and function of the heart in terms of muscular contraction and the working of valves. Identify the main blood vessels to and from the heart, lungs, liver and kidney. Describe the structure of arteries, veins and capillaries in relation to their functions and be able to recognize these vessels from photomicrographs.

The Need for Transport Unicellular and Simple organisms Multicellular organisms Simple diffusion is sufficient for exchange of materials Simple diffusion cannot service the cells deep in tissue layers.

The Need for Transport Unicellular and Simple organisms

The Need for Transport Thus, multicellular organisms found a strategy to solve the problem of access to dissolved gases and removal of waste. They develop a system of channels that service cells that are deep in the body of the organism.

The Need for Transport Sponges are simple organisms with channels and sinuses. Partly dependent on currents.

The Cardiac Cycle