Bellwork1. How many red blood cells can fit through a

capillary at a time?2. Capillaries are how many cells thick?3. How many cells thick are alveoli?4. What two adaptations of alveoli reduce the

distance for gases to diffuse?5. How does the moist lining of each alveolus

affect gas exchange?

Gas exchange is necessary to maintain:

• high levels of O2 (for aerobic respiration)

• low levels of CO2 (waste product)

This gas exchange occurs through dissolution (process of dissolving) and diffusion!

BUT…

How can we get

a higher concentration of O2 and CO2?

Ventilation !

Why Ventilate?

http://www2.estrellamountain.edu/faculty/farabee/BIOBK/insectexch.gif

https://breatheornot.files.wordpress.com/2012/04/insect-diagram.gif

How is air sucked into our lungs (alveoli)?

How is air pushed out of our lungs (alveoli)?

How to Ventilate

http://files.differencebetween.com/wp-content/uploads/2013/11/Processes-of-Inhalation-and-Exhalation.png

BUT…

Why does the air move?Because your lungs don’t do heavy lifting… You lungs are super lazy!They get muscles to do the work.

Boyle’s Gas Law

http://ffden-2.phys.uaf.edu/212_fall2009.web/green_amanda/Images/boylelaw.gif

All molecules want to move from areas of _________ concentration to areas of _________ concentration.

Remember diffusion…

http://upload.wikimedia.org/wikipedia/commons/thumb/2/20/Alveolus2.PNG/375px-Alveolus2.PNG

How do we keep the concentration of gases higher so that they move into and out of the blood?

http://files.differencebetween.com/wp-content/uploads/2013/11/Processes-of-Inhalation-and-Exhalation.png

Inspiration (inhalation) creates

lower pressure inside the lungs.

Expiration (exhalation) creates

higher pressure inside the lungs.

https://www.youtube.com/watch?v=pc2MmhkUW_E

The Ribs and the Diaphragm

http://droualb.faculty.mjc.edu/Course%20Materials/Physiology%20101/Chapter%20Notes/Fall%202007/figure_16_11b_0_labeled.jpg

Ventilation and Gas Exchange

https://www.youtube.com/watch?v=Cy1lfZAIojs