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Circulation: From Air S acs to Heart Facts: Chapter 42: A Learning Adventure

Circulation: From Air S acs to Heart Facts: Chapter 42: A Learning Adventure. By: Bill Nyes the Science Guys. CIRCULATORY SYSTEMS link exchange surfaces with cell throughout the body. Diffusion is inefficient over long distances That’s why there are CIRCULATORY SYSTEMS.

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Circulation: From Air S acs to Heart Facts: Chapter 42: A Learning Adventure

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  1. Circulation: From Air Sacs to Heart Facts: Chapter 42: A Learning Adventure By: Bill Nyes the Science Guys

  2. CIRCULATORY SYSTEMS link exchange surfaces with cell throughout the body • Diffusion is inefficient over long distances • That’s why there are CIRCULATORY SYSTEMS

  3. Animals that lack a distinct CIRCULATORY SYSTEM • Cnidarians and Planarians use a gastrovascular cavity to facilitate exchange with their environment • Most of the cells in cnidarians and planarians are adjacent to the environment so diffusion can occur directly between the cells and the environment

  4. Open and Closed CIRCULATORY SYSTEMS • A CIRCULATORY SYSTEM minimizes the distances that substances must diffuse to enter or leave a cell • The CIRCULATORY SYSTEM has three basic components: circulatory fluid (ex. blood), a set of interconnecting tubes (ex. Veins), and a muscular pump (ex. Heart).

  5. Open CIRCULATORY SYSTEMS • In a open CIRCULATORY SYSTEM, the circulatory fluid, called hemolymph, is the same as the interstitial fluid. • The heart pumps hemolymph through vessels into sinuses • This completes a chemical exchange between hemolymph and body cells.

  6. Closed CIRCULATORY SYSTEM • The circulatory fluid is not the same as the interstitial fluid and is kept separated in closed vessels. • Chemical exchange occurs between the blood and the interstitial fluid, and then between the interstitial fluid and the body cells.

  7. Fact of the Day Do you know what distinguishes an artery and a vein? They are distinguished by the direction that they carry blood; arteries from the heart toward capillaries and veins from capillaries back to the heart. Now you know

  8. Single Circulation • Blood passes through a two chambered heart once in each complete circuit. Animals such as this guy have single circulation

  9. Double Circulation • The CIRCULATORY SYSTEM of mammals, reptiles, and amphibians have two separate circuits, or double circulation. • One pump on the right side of the heart delivers oxygen poor blood to capillary beds of the gas-exchange tissues. After the newly oxygenated blood leaves the gas-exchange tissues, it goes to the left pump where it is sent to organs and tissues throughout the body.

  10. Mammalian Circulation

  11. The Mammalian Heart Terms you should know when discussing the heart • A cardiac cycle is one complete sequence of pumping and filling by the heart • The contraction phase of the cycle is called the systole • The relaxation phase is called the diastole • The volume of blood each ventricle pumps per minute is the cardiac output

  12. The Cardiac Cycle

  13. Heart Valves Valves open and close as the heart goes through rest (diastole) and contraction (systole)

  14. Maintaining the Heart’s Rhythmic Beat

  15. Characteristics of Blood Vessels

  16. Characteristics of Blood Vessels • The endothelium is the thin layer of cells that lines the interior surface of blood vessels • The elastic layer is made up of one layer of endothelial cells (the endothelium) and is supported by an internal elastic lamina.

  17. Characteristics of Blood Vessels

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