The subject for this lecture is the physiology
of the lung. Why do we have lungs? Well it
is essentially is to get oxygen into the blood.
And we need that because oxygen is the main
mechanism for generating ATP by glucose metabolism.
It is essential for aerobic metabolism for
generating energy for all tissues within the
This is a slide that describes an overview
of what happens with the lungs and the physiology
of getting oxygen into the blood. Ventilation,
that is the act of getting air into the lungs,
allows new air with high oxygen concentration
to reach the alveoli. In the alveoli, you
end up with exchange of oxygen into the pulmonary
capillaries and carbon dioxide out of the
pulmonary capillaries back into the alveoli.
And the heart will pump these, the blood circulation
so that oxygenated blood will leave the lung,
go to the left atrium and the left ventricle
and pump around the systemic circulation delivering
oxygen-high blood to the tissues so that they
generate the energy required in the tissues.
Whereas the venous systemic circulation will
return deoxygenated blood to the right side
of the heart and the pulmonary circulation
will deliver that deoxygenated blood to the
alveoli to be oxygenated. And at the bottom
of the slide there are box showing tissue
respiration, that is oxygen consumption by
all the tissues of the body and as a consequent
to that carbon dioxide is produced. So the
purpose of the lung is to deliver oxygen to
the blood and remove that waste carbon dioxide
from the blood returning from the tissues.
If you think about the overview of the lung
physiology there are few steps involved in
1 Ventilation, how air gets into the alveoli.
2 Gas exchange, how oxygen gets into the blood
and how carbon dioxide gets out of the blood
into the alveoli.
3 Perfusion is how the blood gets to the lung.
4 Gas transport is how does the blood transport
gases, oxygen to the tissues, carbon dioxide
from the tissues to the lungs.
5 Then we will talk about ventilation control.
What are the mechanisms by which we alter
the ventilation and respiration to try and
overcome physiological circumstances where
we might need more ventilation, for example
6 The last slide will discuss briefly the
additional functions of the lungs. Because
there are other things that lungs do over
and above oxygen uptake and carbon dioxide