Chapter 27- Gas Exchange
-hemoglobin binds oxygen and transports it throughout the body
-gas exchange make it possible for you to put to work the food molecules the
digestive system provides. -3 phases of gas exchange in humans and other animals
-breathing: As you inhale, oxygen (O2) diffuses across the cells lining the
lungs and into surrounding blood vessels. At the same time, carbon dioxide (CO2)
diffuses from the blood into the lungs. As you exhale, CO2 leaves your body.
-transport of gases by the circulatory system: The O2 that diffused into the
blood attaches to hemoglobin in red blood cells The red vessels in transport O2-
rich blood from the lungs to capillaries in the body’s tissues. The CO2 is also
transported in blood from the tissues back to the lungs carried in the blue
-exchange of gases with body cells: Your cells take up O2 from the blood
and release CO2 to the blood. The gas exchange occurring as we breath is called
-the gas exchange occurring as we breathe is often called respiration.
-cellular respiration requires a continuous supply of O2 and the disposal of CO2.
-gas exchange involves both the respiratory and circulatory systems in servicing
your body’s cells.
27.2 -the part of an animal’s body where gas exchange with the environment occurs
is called the respiratory surface.
-respiratory surfaces are made up of living cells, and like all cells, their plasma
membrane must be wet to function properly.
-respiratory surfaces are always moist and must be large enough to take up
sufficient O2 for every cell in the body.
-gas exchange takes place by diffusion