1. Lecture 5. Gas Exchange
• cellular respiration, oxidative processes within
cells
• external respiration, exchange of O2 and CO2
between the organism and its environment
2. Gas Exchange Surfaces
•
for diffusion to be effective, gas-exchange
regions must be:
–
moist
–
thin
–
relatively large
•
effectiveness of diffusion is enhanced by
vascularization
15. • Lungs of mammals
Mammals ventilate their lungs by negative pressure breathing.
16. • Lungs of birds
http://www.peteducation.com/article.cfm?c=15+1829&aid=2721
17. • Lungs of birds
http://www.peteducation.com/article.cfm?c=15+1829&aid=2721
18. •
the volume of air an animal inhales and exhales
with each breath is called tidal volume
–
it averages about 500 mL in resting humans
•
the maximum tidal volume during forced
breathing is the vital capacity
–
about 3.4 L and 4.8 L for college-age females and
males, respectively
19. •
most animals transport most of the O2 bound
to special proteins called respiratory pigments
–
hemocyanin
–
hemoglobin
20. •
when the
control center
registers a slight
drop in pH, it
increases the
depth and rate
of breathing,
and the excess
CO2 is
eliminated in
exhaled air
21. •
O2 diffuses into pulmonary
capillaries
•
most O2 combines with
hemoglobin in red blood cells
to form oxyhemoglobin
•
CO2 diffuses out of
pulmonary capillaries
•
most CO2 is transported in
the form of bicarbonate ion
•
some CO2 combines with
hemoglobin to form
carbaminohemoglobin
