Full resolution (JPEG) - On this page / på denna sida - XVI. Respiration and Oxidation - I. The Gases of the Blood - Gases of the Lymph and Secretions - II. The Exchange of Gas between the Blood, on the one hand, and Pulmonary Air and the Tissues, on the other
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858 KESPIEATION AND OXIDATION.
fluid, while, on the contrary, the total quantity of carbon dioxide, and
especially the quantity firmly combined, decreases with the quantity
of pus-corpuscles.
H. THE EXCHANGE OF GAS BETWEEN THE BLOOD, ON THE ONE HAND,
AND PULMONARY AH* AND THE TISSUES, ON THE OTHER.
In Chapter I (page 42) it was stated that we are to-day of the
opinion, derived especially from the researches of Pfluger and his
pupils, that the oxidations of the animal body do not take place in the
fluids and juices, but are connected with the form-elements and tissues.
It is nevertheless true that oxidations take place in the blood itself, al-
though, only to a slight extent; but these oxidations depend, it seems,
upon the form-elements of the blood, hence it does not contradict the
above statement that the oxidations exclusively occur in the cells and
chiefly in the tissues.
The gaseous exchange in the tissues, which has been designated
internal respiration, consists chiefly in that the oxygen passes from the
blood in the capillaries to the tissues, while the great bulk of the carbon
dioxide of the tissues originates therein and passes into the blood of the
capillaries. The exchange of gas in the lungs, which is called external
respiration, consists, as is seen by a comparison of the inspired and
expired air, in the blood taking oxygen from the air in the lungs and giving
off carbon dioxide. This does not exclude the fact that in the lungs, as in
every other tissue, an internal respiration takes place, namely, a com-
bustion with a consumption of oxygen and formation of carbon dioxide.
According to Bohr and Henriques x
the lungs take a variable but
sometimes a very important part in the total metabolism. This part,
which on an average is 33 per cent, but may even rise above 60 per
cent of the total metabolism, depends, these experimenters say, upon
the fact that the intermediary metabolic products formed in the tissues
are burnt in the lungs. It is also in part represented by the specific
work of the lungs.
What kind of processes take part in this double exchange of gas?
Is the gaseous exchange simply the result of an unequal tension of the
blood on one side and the air in the lungs or tissues on the other? Do
the gases pass from a place of higher pressure to one of a lower, according
to the laws of diffusion, or are other forces and processes active?
These questions are closely related to that of the tension of the
oxygen and carbon dioxide in the blood and in the air of the lungs and
tissues.
1
Centralbl. f. Physiol., 6, and Maly’s Jahresber., 27.
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