1. Topic 6 & 11: Human Physiology
6.4 Gas exchange

2. Draw, label, and annotate the ventilation system + alveoli diagram
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3. 1 - Ventilation Read & Consider 6.4.1, 6.4.4 - 6.4.6 What do you know?
What questions do you have?

4. Ventilation System
In larger organisms not every cell has access to oxygen sources so a ventilation system is needed to maintain a concentration gradient in alveoli.

5. Respiration

6. Muscles  Ventilation Inspiration –
The diaphragm contracts and flattens downwards
External intercostal muscles contract, pulling ribs up and out  this increases the volume of the thorax
Increased volume decreases the pressure of alveoli and air flow in to equalize pressure
Forced inspiration: accessory neck muscles contract to increase volume

7. Expiration - Passive  Diaphragm relaxes and curves upward.
External intercostal muscles relax, allowing ribs to fall and decreasing the volume of the thorax
This increases the pressure in the alveoli pushing air out of the lungs.
During forced expiration (exercise) internal intercostal muscles and abdominal muscles contract for force exhalation.

8. Pressure Animation -

9. 2 - Exchange Read & Consider 6.4.2 – 6.4.3 What do you know?
What questions do you have?

10. Gas Exchange -
Diffusion of gases; process of swapping one gas for another.  O2 & CO2
Alveoli – O2 diffuses into the blood from the alveoli and CO2 diffuses from the blood to the alveoli
Tissues – O2 diffuses from blood into the cells and CO2 diffuses from cells to the blood.

11. Pneumocytes Type I Type II Extremely attenuated (25nm)
Cover 97% of alveolar surface
Organelles gathered near the nucleus
Vesicles to clear contaminates
Cuboidal in shape
60% of total cells, but <5% of surface area
Production and secretion of surfactant
Act as alveolar stem cells

12. Increasing Diffusion 
Exchange occurs over the body surface or respiratory surface. Diffusion requirements:
Large SA:V  in-foldings (lungs or gills)
Permeable
Thin  efficient up to 1mm thickness
Moist  O2 and CO2 diffuse in solution
Transport system  maintain a concentration gradient
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13. Alveoli

14. Disease
Emphysema
Lung Cancer

15. Practical
How does vigorous exercise affect ventilation rate and tidal volume in humans?

16. "Advanced Practice Providers. " SIU School of Medicine
"Advanced Practice Providers." SIU School of Medicine. SIU School of Medicine, n.d. Web. 24 Oct
Bishop, Adrian. "Lung Cancer Tumours in Smokers Have 10-times More Genetic Mutations." Earth Times. N.p., n.d. Web. 24 Oct
"Laboratory Manual for Exercise Physiology: Pulmonary Function Testing a Valuable Diagnostic Tool." Human-kinetics. N.p., n.d. Web. 24 Oct
"Stock Photo - Human Alveoli, Computer Artwork." Human Alveoli, Computer Artwork. N.p., n.d. Web. 21 Oct
Zyga, Lisa. "Scientists Discover First Multicellular Life That Doesn't Need Oxygen." Phys.Org. N.p., 7 Apr Web. 10 Oct
Works Cited