BIOL273 : Unit 4.docx

• School: University of Waterloo
• Department: Biology
• Course: BIOL273
• Professor: Catherine Studholme

Document Summary

Unit 4: overview of the cardiovascular system & the heart: role of the cardiovascular system (pg 463-464) The problem with being multicellular is that you are very big. Only the surface layer is in contact with environment. We require from the environment: nutrients, water, gas. Rate of diffusion of oxygen and nutrients is limited by distance. Overcome this diffusion limitation by: cardiovascular system for transport of substances through the body, transported by flow of blood through circulatory system, bulk flow rather than diffusion. From the external environment to tissues: nutrients, water, gases. Between tissues of body: wastes, nutrients, hormones. From tissues to external environment: metabolic wastes, gases, heat. Components: heart (pump), blood vessels (vasculate), blood cells & plasma (fluids) Blood vessels: arteries (away), veins (towards: system of valves keep blood moving in one direction, between arteries & veins are a network of capillaries. Divided (functionally) into two separate pumps that work in series: left & right.