Zitat des Tages von August Krogh:
In the tissues generally, and in such a cavity as the abdomen, the pressure is everywhere and practically always very nearly atmospheric, and must be so, because the integuments give way very easily to any excess of pressure, whether positive or negative.
Since muscular contractions are usually more or less regularly alternated with relaxations, the system of valves makes of the veins of every muscle a very effective pump, capable of maintaining a low pressure in the muscle capillaries.
In the numerous observations made in my laboratory upon this object, we have only once seen a combination of vessels in which there might be a direct communication between a small artery and a vein, though the two observers could not come to a final conclusion on the point.
The circulatory system of man and the vertebrate animals can be considered as made up of a small number of organs or subordinate systems, which are easy to recognize anatomically, and the functions of which are on the whole quite distinct.
In many cases of inflammation, the vascular changes develop slowly and long after the application of the stimulus which is responsible for the inflammatory reaction.
Muscles do not use oxygen at a constant rate.
There can be little doubt that fishes swimming rapidly do not make respiratory movements at all, but obtain the necessary ventilation of the gills simply by opening the mouth.
I found it possible to observe at least the superficial capillaries of muscles both in the frog and in mammals through a binocular microscope, using strong reflected light as a source of illumination. Resting muscles observed in this way are usually quite pale, and the microscope reveals only a few capillaries at fairly regular intervals.
