05/12/07 SBI3U | A. Manaktola The Task of Transportation An Introduction to the Circulatory System

05/12/07 SBI3U | A. Manaktola The Need for a Specialized Transport System Multicellular organisms cannot rely on diffusion or active transport to bring materials from the external environment to cells of the internal tissues quickly enough to meet the cells’ metabolic requirements

05/12/07 SBI3U | A. Manaktola Circulatory Systems A circulatory system has three parts: 1.A fluid in which materials are transported 2.A network of tubes or body spaces through which the fluid flows 3.A means of driving fluid through the spaces or blood vessels

05/12/07 SBI3U | A. Manaktola The Open Transport System Only one blood vessel (aorta) Blood flows into the tissue and comes into direct contact with all cells Grasshopper’s blood is colourless because it does not contain any hemoglobin, only carries nutrients

05/12/07 SBI3U | A. Manaktola The Closed Transport System The worm has five pairs of blood vessels called aortic arches, which serve as the worm’s hearts Pump from Dorsal  Ventral Blood carries oxygen and carbon dioxide in addition to nutrients, and inside the vessels at ALL times Blood is red (when oxygenated) because it contains hemoglobin

05/12/07 SBI3U | A. Manaktola Explore! Complete the Comparative Hearts activity by examining the circulation patterns of different vertebrates.