Transcript Gas Exchange at Cellular Level

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/gasExchang
e.swf
Hemoglobin Transport
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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