11.3 Gas Exchange Notes
Respiration includes external respiration and internal respiration.
•
____________________: exchange of gases in the lungs
•
____________________: exchange of gases in the tissues
Most of the oxygen carried in the blood is attached to
_____________________, a protein found in red blood cells.
Partial Pressure
Diffusion
Enzymes
External Respiration: gas exchange at the __________________ between
__________________________________
O2: __________________________
Blood Approaching the lungs has a _________________________
than the air in the alveoli

O2 diffuses into the blood

O2 binds to _______________; _____________________
CO2: ________________________________
Blood has a ________________________ of CO2 (PCO2) than air
•
__________________ (HCO3-) are converted back to CO2
•
Carbonic anhydrase speeds up this reaction too
Internal Respiration: gas exchange
at the __________________ between
__________________________________
O2: _______________________
Partial ________________:
pressure of O2 (PO2) inbreathing
tissue is ______________than
in blood
too much removes H+ from
the
o _____________________ gives up O2, which diffuses
blood. This
resulting
in ___________________
outlowers
of theblood
bloodpH
into
the tissues
CO2: ___________________________
CO2 diffuses into the blood: the PCO2 of tissue is ______________ than in blood
3 ways CO2 is transported:
1. Some CO2 is transported ______________________________
2. 10% binds to ______________________________________________
3. The remaining CO2 combines with water in the plasma,
forming _____________________ (H2CO3),
which dissociates into ________________ (H+) and _____________________

____________________________ is an enzyme that speeds up the reaction
•
this reaction uses up CO2, _________________________________ so that more CO2 can diffuse out of the tissue
hemoglobin combines with excess H+ to become reduced hemoglobin (HHb) – _______________________

avoids ________________________________ – too much CO2 , resulting in low H+ (acidic blood)
When blood reaches the lungs, CO2 readily diffuses out of the blood and is exhaled