1. Gases in, Gases Out Page 447-451
Respiration
Gases in, Gases Out
Page

2. Gas Exchange
The alveoli exchange gases with the blood as the gases move from ___________c oncentration

3. The Air We Breathe
Air has relatively:
High O2
Low CO2

4. The Air We Breathe
Concentrations of gases are usually described in terms of __________
The more gas there is, the more _______ it exerts on surrounding environment
The air at sea level has an atmospheric pressure of kPa

5. The Air We Breathe
Partial Pressure: the pressure of an _______________ in a sample
The sum of the partial pressures in a sample will equal the _____________
As O2 makes up 20.9% of the air, it has a partial pressure of 21.2kPa (20.9% of kPa)
Carbon dioxide has a partial pressure of kPa

6. Gas Exchange
Gases move from _____ partial pressure to _____ partial pressure

7. Gas Exchange
Explain this:

8. Gas Exchange
Oxygen in the alveoli is 13.3 kPa while it is about 5.3 kPa in the blood
Oxygen diffuses until blood oxygen is kPa
Using this mechanism, 1L of blood will carry 3 mL of O2

9. Hemoglobin
Protein in the blood that binds to _______

10. Hemoglobin Made up of four subunits
Each subunit surrounds a _______ group

11. Hemoglobin
Heme group

12. Hemoglobin
Heme group
Circular, ring structure with an ___ ion in the middle
The ___ ion is capable of binding to O2

13. Hemoglobin
Works by binding to oxygen that has become dissolved in the blood
Oxyhemoglobin gives blood a bright red color
Allows the blood to carry much more oxygen than it normally could
Blood with hemoglobin can carry 200mL of oxygen per 1L of blood
An increase of 70x

14. Gas Exchange
Oxygenated blood travels to the cells of the body where it diffuses into the cells
The partial pressure in the blood is 13.3 kPa while it only kPa in the cells
As pressure in the blood decreases, hemoglobin releases it’s oxygen
Carbon dioxide also diffuses out of the cell into the blood
Partial pressure is 5.6 kPa in the cell and 5.33 kPa in the blood

15. Carbon dioxide in the blood
Undergoes a serious of steps:
CO2 + H2O  H2CO3
H2CO3  H+ + HCO3-
The H+ causes the blood to be _______

16. Carbon dioxide in the blood
The hemoglobin that is no longer carrying oxygen is able to bind to these H+ ions
This reduces the _______ of the blood

17. Carbon dioxide in the blood
Back in the lungs, the hemoglobin releases the H+ as it would much rather bind to the ________
The released H+ undergoes this reaction:
H+ + HCO3-  CO2 + H2O
Carbon dioxide diffuses out of blood into the alveoli
Partial pressure of CO2 in blood is 5.6 kPa and only kPa in alveoli

18. Thought questions for homework
Why is it important for the partial pressures of O2 and CO2 to be different in the alveoli than it is in the surrounding air we breathe?
How does altitude affect our breathing?