Absorption may also take place from the skin, from the rectum, from the respiratory passages, or from wounds, and from direct injection into the subcutaneous tissue or into a blood vessel.
The action on the circulation is largely secondary, however, to the all-important action of opium on the respiratory centre in the medulla oblongata.
This may occur suddenly, as when the resistance is increased in the arterial system by a e on f sudden exertion or strain, and more slowly when the resistance is increased in the pulmonary circulation of the by inflammation of the respiratory passages.
This system is in no true sense a vascular system; there are no capillaries, and the fluid it contains, which is corpusculated, can hardly have a respiratory or nutritive function.
Such could hardly be obtained in any other way by those worms that have no special respiratory apparatus, and that live in mud and under stones where the natural supply of freshly oxygenated sea-water is practicaily limited.
This view was hotly contested by many workers and it was sought to explain the trichogyne - without much success - as a respiratory organ, or as a boring organ which made a way for the developing apothecium.
Br, The bract devoid of muscles and respiratory in function.
In all cases there is a longer or shorter period of excitement, followed by intoxication or narcosis, and with large doses this passes into paralysis and death from depression of the respiratory centre or of the heart.
Alimentary, Respiratory and Excretory Systems. - Although the function of the two latter systems of organs is the purification of the blood, they are not usually considered together, and it is therefore the more remarkable that their close association in Amphioxus renders it necessary to treat them in common.
The chief interest of the place centres in its brine springs which are largely impregnated with carbonic acid gas and oxide of iron, and are efficacious in chronic catarrh of the respiratory organs, in liver and stomach disorders and women's diseases.