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The immediate following second rise not so high as that of the auricular contraction is known as the ventricular wave, and corresponds to the dicrotic wave in the radial. The next lesser decline shows ventricular diastole, or the heart rest. A tracing of the jugular vein shows the activity of the right side of the heart.
Absorption of some toxins or poisons which could act on the blood supply of the ventricles could also be a cause of this condition. This irregular ventricular contraction sometimes displaces the apex beat. Ztschr. f. He also found that compression of this nodal region of the auricle from some growth or other disturbance in the mediastinal region could cause auricular fibrillation. Arch. f. klin.
The cause may be more or less functional and removable, such as tea, coffee, alcohol, tobacco, gastric indigestion and intestinal toxemia; or it may be due to functional disturbances of the heart, such as that due to what has been termed extrasystole, or to irregular ventricular contractions.
When these intermittences are regular, perhaps two beats to one intermittence, or three beats to one intermittence are the most frequent types. When the auricles also beat slowly, perhaps the vagiare for some reason overstimulated and thus inhibit the heart's activity. The attacks of syncope are doubtless due to anemia of the medulla, because of the infrequent ventricular contractions.
The rate of conduction, Lewis believes, depends on the glycogen content of the structures, the Purkinje fibers, where conduction is most rapid, containing the largest amount of glycogen, the auricular musculature containing the next largest amount of glycogen, and the ventricular muscle fibers the least amount of glycogen.
When at length, and after the lapse of a few days, the outline of the body begins to be distinguished, then is the ventricular part of the heart also produced, but it continues for a time white and apparently bloodless, like the rest of the animal; neither does it pulsate or give signs of motion.
The number of ventricular contractions was increased, but not enough to indicate the complete removal of the heart block. Med. These stimuli are irregular in intensity, and the contractions caused are irregular in degree. If the wave lengths of the pulse tracing show no regularity- -if, in fact, hardly two adjacent wave lengths are alike the disturbance is auricular fibrillation.
While most authorities on the voice advocate the system of breath-control by "opposed muscular action," there are a number of masters who teach an entirely different system. This is usually known as the "Breath-band," or "Ventricular" breath-control. Charles Lunn, in The Philosophy of the Voice, 1878, was the first to propound the theory that the breath may be controlled by the false vocal cords.
His explanations were practically the same as those given to-day first the contraction of the auricle, sending blood into the ventricle; then ventricular contraction, making the pulse, and sending the blood into the arteries. He had thus demonstrated what had not been generally accepted before, that the heart was an organ for the propulsion of blood.
In all Mammals, each cerebral hemisphere contains a cavity which is termed the 'ventricle, and as this ventricle is prolonged, on the one hand, forwards, and on the other downwards, into the substance of the hemisphere, it is said to have two horns or 'cornua', an 'anterior cornu, and a 'descending cornu. When the posterior lobe is well developed, a third prolongation of the ventricular cavity extends into it, and is called the "posterior cornu."
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