blood leaves the heart to go to the lungs through the pulmonary artery vessel.
blood leaves the heart to go to the lungs through the pulmonary artery vessel.
through which vessel does blood leave the heart to go to the lungs?
pulmonary artery
the left and right sides of the heart are named from a dorsal view, i.e., looking at the heart from the back or from the perspective of the person whose heart it is. there are four chambers in a heart: an atrium (upper) and a ventricle (lower) on both the left and right sides. in mammals and birds, blood from the body goes to the right side of the heart first. blood enters the upper right atrium, is pumped down to the right ventricle and from there to the lungs via the pulmonary artery. blood going to the lungs is called the pulmonary circulation. when the blood returns to the heart from the lungs via the pulmonary vein, it goes to the left side of the heart, entering the upper left atrium. blood is then pumped to the lower left ventricle and from there out of the heart to the body via the aorta. this is called the systemic circulation. a cardiac shunt is when blood follows a pattern that deviates from the systemic circulation, i.e., from the body to the right atrium, down to the right ventricle, to the lungs, from the lungs to the left atrium, down to the left ventricle and then out of the heart back to the systemic circulation.
cardiac shunt
this work is a substantial contribution to cardiac physiology, for it introduces into biology the doctrine of circulation of the blood in the seventeenth century. opposed and obliging work heralding harvey's discovery go back to the thirteenth century, when the pulmonary circulation and gas exchange was proposed by ibn al-nafis. both long since proven theories are incomplete when studied separately but together form core knowledge of present-day cardiology. in 1553, michael servetus said that blood flows from the heart to the lungs, and that it there mixes with air to form the arterial blood which flows back to the heart. between 1570 and 1590, cesalpino suggested, in a controversy with galenists, that the movement of blood was more like a circulation than an oscillation; but this view lacks clarity. in 1603, hieronymus fabricius ab acquapendente published a work clearly describing the valves in the veins and showing that they hinder the flow of blood away from the heart. from 1597 to 1602, harvey studied arts and medicine at padua, and made a careful study of the heart and the movement of blood. by 1616, he was presenting in lectures his case for the circulation of the blood, but it was not until 1628 that he published it in his classic work, "de motu cordis et sanguinis". this book is important both for the discovery of the complete circulation and for the experimental, quantitive and mechanistic methodology which harvey introduced. he looked upon the heart, not as a mystical seat of the spirit and faculties, but as a pump analyzable along mechanical lines. he also measured the amount of blood which it sent out to the body. he observed that with each beat two ounces of blood leave the heart; so that with 72 heart beats per minute, the heart throws into the system 540 pounds of blood every hour. where could all this blood come from? the answer seems to be that it is the same blood that is always returning. moreover, the one-way valves in the heart, like those in the veins, indicate that, following the pulmonary circulation, the blood goes out to all parts of the body through the arteries and returns by way of the veins. the blood thus makes a complete closed circuit. as harvey expressed it, "there must be a motion, as it were, in a circle." there was, however, one stage in the circulation which harvey was not able to see - that in which the veins and arteries lose themselves by subdivision into the tiny capillary vessels. it was in 1660, three years after harvey's death, that marcello malpighi saw the blood moving in the capillaries of a frog's lung, and thus supplied the missing link in harvey's proof of the circulation of the blood.
exercitatio anatomica de motu cordis et sanguinis in animalibus