Main Arguments
Overview
The prevalent theory before Harvey is that of Galen. In summary, Galen’s theory did not state the circulation of blood, but believed that blood is created in the liver by transforming part of the ingesta. It was also believed that the active movement of the heart was the diastole (relaxation) instead of the systole (contraction). Another thing that was believed was that the circumflex (the wall dividing the left and right ventricles) had pores that allowed the passing of blood from the left to the right ventricle.
Harvey’s contributions to a precise theory of the heart had great impact on the development of medicine and to other areas as well. You can see in Harvey’s book how he delicately writes and you can perceive even some fear of danger he had when publishing it. This is because his theory was revolutionary and it would’ve change the perspective of man and the world, of man and God, and of man and man. Besides, a lot if not all of the previous theories would be thrown away. We can say that Copernicus is to Harvey as heliocentrism is to the circulation of blood.
Main Arguments
Some Basics
The heart is composed of two atriums or auricles and two ventricles. The ventricles are divided by the circumflex.
The heart has two movements; the diastole and the systole. The diastole is the movement of relaxation where the heart is seen to expand. The systole is the movement of contraction.
The heart, when seen from the front, would have its sides shifted from yours. That is, your right side will be the heart’s left side and vice versa.
Now the Arguments…
1. The active movement of the heart is the systole, a movement in which the heart expels the blood.
2. The heart functions in two synchronized movements. First, the two auricles and then the two ventricles.
3. The whole heart is not the primum vivens, ultimum moriens (the first part to live, the last to die), but the right auricle is that part. This is observed in the embryo of a chick, when Harvey saw, in the midst of a cloudlet, a little drop of blood so tiny that it seems to disappear and appear.
4. Blood is not produced by ingesta by the liver. This is proved by making the calculation of how much blood it would be required for the liver to produce in half an hour. Even with smaller than normal quantities, the amount the liver would have to produce surpasses by a lot the quantity of ingesta and that of the capacity of the liver.
5. Because the blood is not produced by the liver, it goes into a circular motion in the body. In this case, veins are the ones where blood is taken from all the body to the heart and the arteries are where blood travels from the heart to the rest of the body. The veins carry the “bad”, unhealthy, or used blood and the arteries carry the healthy and spirited blood.
6. The veins go from the rest of the body to the heart, and these have valves that don’t allow blood to travel the other way. This is proved by the experiment of the arm, where he blocks one valve and then pushes the blood upward in the direction of the heart. By doing this, it can be seen that the vein is not filled again, but remains empty and when the valve is released, the vein is filled up again.
7. The vena cava is the vein that connects all the veins to the right auricle of the heart. Then, the auricle pushes the blood to the right ventricle. This ventricle pumps the blood to the pulmonary artery, which in turn takes the blood to the lungs where it is rejuvenated or cleaned. After this, is goes into the pulmonary veins, which carry it to the left atrium and then to the left ventricle. Finally, the left ventricle pumps the blood to the arteries, which will carry it to the rest of the body. Because of this great effort, the left side of the heart is seen to be much more muscular and bigger than the right side. All of these were proved by the experiment where Harvey blocks the pulmonary veins and then arteries in order to see that the blood necessarily travels in the path described previously. This also eliminates the notion that the circumflex contains pores that allow the blood to pass from the right to the left ventricle.
The prevalent theory before Harvey is that of Galen. In summary, Galen’s theory did not state the circulation of blood, but believed that blood is created in the liver by transforming part of the ingesta. It was also believed that the active movement of the heart was the diastole (relaxation) instead of the systole (contraction). Another thing that was believed was that the circumflex (the wall dividing the left and right ventricles) had pores that allowed the passing of blood from the left to the right ventricle.
Harvey’s contributions to a precise theory of the heart had great impact on the development of medicine and to other areas as well. You can see in Harvey’s book how he delicately writes and you can perceive even some fear of danger he had when publishing it. This is because his theory was revolutionary and it would’ve change the perspective of man and the world, of man and God, and of man and man. Besides, a lot if not all of the previous theories would be thrown away. We can say that Copernicus is to Harvey as heliocentrism is to the circulation of blood.
Main Arguments
Some Basics
The heart is composed of two atriums or auricles and two ventricles. The ventricles are divided by the circumflex.
The heart has two movements; the diastole and the systole. The diastole is the movement of relaxation where the heart is seen to expand. The systole is the movement of contraction.
The heart, when seen from the front, would have its sides shifted from yours. That is, your right side will be the heart’s left side and vice versa.
Now the Arguments…
1. The active movement of the heart is the systole, a movement in which the heart expels the blood.
2. The heart functions in two synchronized movements. First, the two auricles and then the two ventricles.
3. The whole heart is not the primum vivens, ultimum moriens (the first part to live, the last to die), but the right auricle is that part. This is observed in the embryo of a chick, when Harvey saw, in the midst of a cloudlet, a little drop of blood so tiny that it seems to disappear and appear.
4. Blood is not produced by ingesta by the liver. This is proved by making the calculation of how much blood it would be required for the liver to produce in half an hour. Even with smaller than normal quantities, the amount the liver would have to produce surpasses by a lot the quantity of ingesta and that of the capacity of the liver.
5. Because the blood is not produced by the liver, it goes into a circular motion in the body. In this case, veins are the ones where blood is taken from all the body to the heart and the arteries are where blood travels from the heart to the rest of the body. The veins carry the “bad”, unhealthy, or used blood and the arteries carry the healthy and spirited blood.
6. The veins go from the rest of the body to the heart, and these have valves that don’t allow blood to travel the other way. This is proved by the experiment of the arm, where he blocks one valve and then pushes the blood upward in the direction of the heart. By doing this, it can be seen that the vein is not filled again, but remains empty and when the valve is released, the vein is filled up again.
7. The vena cava is the vein that connects all the veins to the right auricle of the heart. Then, the auricle pushes the blood to the right ventricle. This ventricle pumps the blood to the pulmonary artery, which in turn takes the blood to the lungs where it is rejuvenated or cleaned. After this, is goes into the pulmonary veins, which carry it to the left atrium and then to the left ventricle. Finally, the left ventricle pumps the blood to the arteries, which will carry it to the rest of the body. Because of this great effort, the left side of the heart is seen to be much more muscular and bigger than the right side. All of these were proved by the experiment where Harvey blocks the pulmonary veins and then arteries in order to see that the blood necessarily travels in the path described previously. This also eliminates the notion that the circumflex contains pores that allow the blood to pass from the right to the left ventricle.