Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: July 20, 2025
It should be remembered that the diastolic pressure represents the pressure which the left ventricle must overcome before the blood will begin to circulate, that is, before the aortic valve opens, while the pressure pulse represents the power of the left ventricle in excess of the diastolic pressure.
The wall of the right ventricle may now be raised and the cavity exposed. Now cut through the middle of the loosened ventricular wall from the apex to the middle of the right auricle, laying it open for observation. Observe the openings into the auricle, there being one each for the vena cava superior, the vena cava inferior, and the coronary vein.
When the foetus is farther advanced, when the bones can be distinguished from the fleshy parts and movements take place, then it also has a heart which pulsates, and, as I have said, throws blood by either ventricle from the vena cava into the arteries. These points will be found elsewhere confirmed by numerous observations on the formation of the foetus.
Morand gives an instance of survival for five days after wound of the right ventricle. Saucerotte speaks of survival for three days after injury to the heart. Babington speaks of a case of heart-injury, caused by transfixion by a bayonet, in which the patient survived nine hours.
Sixthly, The cold-blooded animals, as the fish-tribes, which are furnished with but one ventricle of the heart, and with gills instead of lungs, and with fins instead of feet or wings, bear a great similarity to each other; but they differ, nevertheless, so much in their general structure from the warm-blooded animals, that it may not seem probable at first view, that the same living filament could have given origin to this kingdom of animals, as to the former.
Finally, on leaving the gills the blood is received by an arterial heart, with only one ventricle like that of the crustaceans, in the shape of a small pear, similar to ours, having an auricle, and an aorta, branching out so as to distribute the blood throughout the whole body.
If the work is too heavy, and the systolic blood pressure is rapidly increased, it may become so great as to prevent the left ventricle from completely evacuating its content. The heart then increases in size and may sooner or later become strained; if this strain is severe, an acute dilatation may of course occur, even in an otherwise well person. Such instances are not infrequent.
From here a narrow duct, called "the aqueduct of Sylvius," passes through the corpus quadrigeminum to the third cerebral ventricle, which lies between the two optic thalami; and this in turn is connected with the pairs of lateral ventricles which lie to the right and left in the large hemispheres. Thus all the cavities of the central marrow are directly interconnected.
Such are fibroid changes in the lungs, emphysema, prolonged chronic bronchitis, the last stages of pulmonary tuberculosis, old neglected pleurisies with cirrhosis or fibrosis of the lung, and repeated attacks of asthma anything, whether valvular defect or pulmonary circulatory disturbance, which increases the pressure ahead and the work of this ventricle.
This lesion, from the frequent overdistention of the left ventricle, is one which often causes pain. While the left ventricle enlarges enormously to overcome the extra distention due to the blood entering the ventricle from both directions, the muscle sooner or later becomes degenerated from poor coronary circulation.
Word Of The Day
Others Looking