Bellwork
1. 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
Remember diffusion…
All molecules want to move from areas of
_________ concentration to areas of
_________ concentration.
How do we keep the
concentration of gases higher so
that they move into and out of the
blood?
http://upload.wikimedia.org/wikipedia/commons/thumb/2/20/Alveolus2.PNG/375px-Alveolus2.PNG
Inspiration (inhalation) creates
lower pressure inside the lungs.
Expiration (exhalation) creates
higher pressure inside the lungs.
http://files.differencebetween.com/wp-content/uploads/2013/11/Processes-of-Inhalation-and-Exhalation.png
The Ribs and the
Diaphragm
https://www.youtube.com/watch?v=pc2MmhkUW_E
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