Gas Exchange at Cellular Level By Nora, Duncan and Adrienne
Basic Gas Exchange • When you inhale air, oxygen is picked up by red blood cells, which circulate through the bloodstream and provide oxygen to other parts of the body. • Blood cells also pick up carbon dioxide molecules --> they are brought back to the lungs and exhaled.
Cell Respiration Animation http://ilo.ecb.org/SourceFiles/gasExchange.swf
Hemoglobin Transport • Red blood cells contain hemoglobin, a protein which bonds to oxygen to allow it to be transported. • Hemoglobin without oxygen appears bluish-purple, while hemoglobin with oxygen appears red. • This is why blood sometimes looks blue. • Because hemoglobin carries oxygen away from the lungs, much more oxygen is able to enter the body because the movement of the hemoglobin keeps the oxygen level near the lungs low, allowing more to diffuse out of the lungs.
Hemoglobin Structure • Hemoglobin is made of four polypeptide chains and four heme groups: it allows four oxygen molecules to bind to it. • Iron is essential to create hemoglobin. Too little iron in the diet is one cause of anemia, a disorder that interferes with the diffusion of oxygen.
Capillaries • There are three types of blood vessels in the body: arteries, veins, and capillaries. • Capillaries are very narrow, and their cell walls are 5-10 microns thick.
Respiration In Non-Optimal Environments • High Altitude: • Better efficiency of oxygen is needed in higher altitudes due the lack of oxygen in the environment • With less oxygen in system, one’s kidney fails to produce an abundance of erythropoietin: a hormone that makes new red blood cells • In high altitudes, one needs the most efficiency of oxygen delivery as possible; an abundance of red blood cells is necessary • Stress: • Causes circulating blood cells to increase • When the concentration of blood cells increase, kidneys stop secreting erythropoietin
Respiration In Non-Optimal Conditions cont… • Deep Diving: • During deep dives, blood travels away from organs and towards extremities in the body--> causes body functions to slow down • Increase pressure= more gaseous nitrogen, which dissolves into body tissue
Where does gas exchange occur? • In the capillaries • The thin walls of capillaries allows for gaseous diffusion • The walls of arteries and veins = too thick for diffusion to happen