Opening up blood circulation
William Harvey concluded that a snake bite is only dangerous because the venom spreads through the vein from the bite site throughout the body. For English doctors, this guess became the starting point for reflections that led to the development of intravenous injection... It is possible, the doctors reasoned, to inject one or another medicine into a vein and thereby inject it into the entire body. But the next step in this direction was taken by German doctors, applying a new surgical enema on a person (as the intravenous injection was then called). The first injection experience was made by one of the most prominent surgeons of the second half of the 17th century, Matheus Gottfried Purman from Silesia. The Czech scientist Pravac proposed a syringe for injection. Before that, syringes were primitive, made from pig bladders, with wooden or copper nozzles embedded in them. The first injection was made in 1853 by English doctors.
After arriving from Padua, simultaneously with his practical medical activities, Harvey carried out systematic experimental research the structure and work of the heart and the movement of blood in animals. He first expounded his thoughts in the next Lumley lecture he gave in London on April 16, 1618, when he already had a lot of material from observations and experiments. Harvey summed up his views with the words that blood moves in a circle. More precisely - in two circles: small - through the lungs and large - through the whole body. His theory was incomprehensible to the audience, it was so revolutionary, unusual and alien to traditional ideas. Harvey's "Anatomical Study of the Movement of the Heart and Blood in Animals" was born in 1628 and was published in Frankfurt am Main. In this study, Harvey refuted Galen's dominant teachings of 1500 years about the movement of blood in the body and formulated new ideas about blood circulation.
Of great importance for Harvey's research was detailed description venous valves that direct the movement of blood to the heart, first given by his teacher Fabrice in 1574. The simplest and at the same time the most convincing proof of the existence of blood circulation, proposed by Harvey, was to calculate the amount of blood passing through the heart. Harvey showed that in half an hour, the heart emits an amount of blood equal to the weight of the animal. Such a large number of moving blood can only be explained on the basis of the concept of a closed circulatory system. Obviously, Galen's assumption about the continuous destruction of blood flowing to the periphery of the body could not be reconciled with this fact. Another proof of the erroneousness of the views about the destruction of blood on the periphery of the body, Harvey received in the experiments of applying a bandage to the upper limbs of a person. These experiments showed that blood flows from arteries to veins. Harvey's studies have identified the importance of the pulmonary circulation and established that the heart is a muscular sac equipped with valves, the contractions of which act as a pump that pumps blood into the circulatory system.
Ancient scientists and scientists of the Renaissance had very peculiar ideas about movement, the meaning of the heart, blood and blood vessels. For example, Galen says: “Parts of food, absorbed from the alimentary canal, are brought by the portal vein to the liver and, under the influence of this large organ, are converted into blood. The blood, thus enriched with food, endows these very organs nutritional properties, which are summed up in the expression "natural perfume", but the blood endowed with these properties is still unfinished, unsuitable for the higher purposes of blood in the body. Brought from the liver through v. cava to the right half of the heart, some parts of it pass from the right ventricle through countless invisible pores to the left ventricle. When the heart expands, it sucks air from the lungs through the venous artery, the "pulmonary vein," into the left ventricle, and in this left cavity, the blood that has passed through the septum mixes with the air thus sucked there. With the help of the warmth that is innate to the heart, placed here as a source of body heat by God at the beginning of life and remaining here until death, it is saturated with further qualities, loaded with "life spirits" and then it is already adapted to its external duties. The air thus pumped into the left heart through the pulmonary vein at the same time softens the innate warmth of the heart and prevents it from becoming excessive. "
Vesalius writes about blood circulation: “Just as the right ventricle sucks blood from v. cava, the left ventricle pumps air from the lungs into itself every time the heart relaxes through the vein-like artery, and uses it to cool the innate warmth, to nourish its substance and to prepare life spirits, producing and purifying this air so that it, together with blood that seeps out in enormous quantities through the septum from the right ventricle to the left can be destined for the large artery (aorta) and thus for the whole body. "
Miguel Servet (1509-1553). Its burning is depicted in the background.
The study of historical materials testifies that the pulmonary circulation was discovered by several scientists independently of each other. The first to open the small circle of blood circulation in the XII century was the Arab physician Ibn al-Nafiz from Damascus, the second was Miguel Servet (1509-1553) - a lawyer, astronomer, metrologist, geographer, physician and theologian. He listened to the lectures of Sylvius and Gunther in Padua and, possibly, met with Vesalius. He was a skilled physician and anatomist, since his conviction was the knowledge of God through the structure of man. VN Ternovsky assessed the unusual direction of the theological teaching of Servetus: “Knowing the spirit of God, he had to know the spirit of man, to know the structure and work of the body in which the spirit dwells. This compelled him to conduct anatomical research and geological work "Servetus published the books" On the Fallacies of the Trinity "(1531) and" The Restoration of Christianity "(1533). The last book was burned by the Inquisition, like its author. Only a few copies of this book have survived. In it, among theological discourses, a small circle of blood circulation is described: “... in order, however, so that we can understand that blood becomes living (arterial), we must first study the emergence in the substance of the vital spirit itself, which is composed and nourished from inhaled air and very thin blood. This vital air arises in the left ventricle of the heart, the lungs especially help in relation to its improvement; it is a subtle spirit, generated by the power of heat, yellow (light) color, an igniting force, so that it is as if it were a radiating vapor from purer blood containing the substance of water, air with the produced steam, and which passes from from the right ventricle to the left. This transition, however, does not occur, as is commonly thought, through the medial wall (septum) of the heart, but in a remarkable way, gentle blood is driven through a long path through the lungs. "
William Harvey (1578-1657)
Truly understood the meaning of the heart and blood vessels, William Harvey (1578-1657), an English physician, physiologist and experimental anatomist, who in his scientific activities was guided by the facts obtained in the experiments. After 17 years of experimentation, Harvey in 1628 published a small book "Anatomical study of the movement of the heart and blood in animals", where he pointed to the movement of blood in a large and small circle. The work was deeply revolutionary in the science of that time. Harvey failed to show the small vessels connecting the vessels of the large and pulmonary circulation, nevertheless, the prerequisites were created for their discovery. Since the discovery of Harvey, genuine scientific physiology begins. Although the scholars of that time were divided into adherents of Gachen and Harvey, in the end, Harvey's teachings became generally accepted. After the invention of the microscope, Marcello Malpighi (1628-1694) described the blood capillaries in the lungs and thereby proved that the arteries and veins of the large and pulmonary circulation are connected by capillaries.
Harvey's thoughts on blood circulation influenced Descartes, who hypothesized that the processes in the central nervous system are automatic and do not constitute the human soul.
Descartes believed that nerve "tubes" radiate radially from the brain (as from the heart), carrying automatically reflections to the muscles.
Circles of blood circulation represent the structural system of blood vessels and components of the heart, inside which blood is constantly moving.
Circulation plays one of the most important functions of the human body, it carries in itself blood flows, enriched with oxygen and nutrients necessary for tissues, removing metabolic decay products from tissues, as well as carbon dioxide.
The transport of blood through the vessels is the most important process, so that its deviations lead to the most serious burdens.
The circulation of blood flows is divided into small and big circle circulation of blood. They are also referred to as systemic and pulmonary, respectively. Initially, the systemic circle enters from the left ventricle, through the aorta, and enters the right atrial cavity, completes its journey.
The pulmonary circulation of blood starts from the right ventricle, and entering the left atrium ends its path.
Who first identified the circles of blood circulation?
Due to the fact that in the past there were no devices for apparatus research of the body, the study physiological characteristics a living organism was not possible.
The studies were carried out on corpses, in which doctors of that time studied only anatomical features, since the heart of the corpse was no longer contracting, and circulatory processes remained a mystery for specialists and scientists of the past.
They had to simply speculate on some physiological processes, or use their imagination.
The first assumptions were the theories of Claudius Galen, back in the II century. He studied the science of Hippocrates, and put forward the theory that the arteries inside themselves carry air cells, and not blood masses. As a result, for many centuries they tried to prove it physiologically.
All scientists were aware of what the structural system of blood circulation looks like, but could not understand by what principle it functions.
Miguel Servetus and William Harvey made a big step in organizing the data on the functioning of the heart already in the 16th century.
The latter, for the first time in history, described the existence of the systemic and pulmonary circulation, back in one thousand six hundred and sixteen, but was never able to explain in his works how they are related to each other.
Already in the 17th century, Marcello Malpighi, who began to use the microscope for practical purposes, one of the first people in the world, discovered and described that there are small capillaries that are not visible with a simple eye, they connect two circles of blood circulation.
This discovery was challenged by the geniuses of those times.
How did blood circulation circles evolve?
As the class "vertebrates" developed more and more both anatomically and in terms of physiology, an increasingly developed structure was also formed. cordially- vascular system.
The formation of a vicious circle of blood movement occurred for a greater speed of movement of blood flows in the body.
When compared with other classes of animal creatures (take arthropods), in chordates, the initial formations of blood movement along vicious circle... The lancelet class (a genus of primitive marine animals) does not have a heart, but has an abdominal and dorsal aorta.
The heart, consisting of 2 and 3 chambers, is observed in fish, reptiles and amphibians. But already in mammals, a heart with 4 chambers is formed, where there are two circles of blood circulation that do not mix with each other, as such a structure is recorded in birds. The formation of two circles of circulation is the evolution of the cardiovascular system, which has adapted to the environment.
Types of vessels
The entire blood circulation system consists of the heart, which is responsible for ensuring that the blood is pumped, and its constant movement in the body, and the vessels inside which the pumped blood is distributed.
Many arteries, veins, as well as small-sized capillaries make up a closed circle of blood circulation with their multiple structure.
Mostly large vessels, which are in the shape of a cylinder and are responsible for the movement of blood from the heart to the feeding organs, make up the systemic circulation.
All arteries have elastic walls, which contract, as a result of which the blood moves evenly and in a timely manner.
Vessels have their own structure:
- Inner endothelial membrane. It is strong and elastic, it directly interacts with blood;
- Smooth muscle elastic tissue. Make up the middle layer of the vessel, are more durable and protect the vessel from external damage;
- Connective tissue sheath. Is the outermost layer of the vessel, covering them along the entire length, protects the vessels from external influences on them.
The veins of the systemic circle help blood flow from small capillaries directly to the tissues of the heart. They have the same structure as the arteries, but are more fragile, since the middle layer contains less tissue and is less elastic.
In view of this, the speed of blood flow through the veins is influenced by the tissues located in the immediate vicinity of the veins, and especially the muscles of the skeleton. Almost all veins contain valves that prevent blood from moving in the opposite direction. The only exception is the vena cava.
The smallest components of the structure of the vascular system are capillaries, the cover of which is a single-layer endothelium. They are the smallest and shortest types of vessels.
It is they who enrich the tissues with useful elements and oxygen, removing from them the remnants of metabolic decay, as well as processed carbon dioxide.
Blood circulation in them occurs more slowly, in the arterial part of the vessel, water is transported to the intercellular zone, and in the venous part, a drop in pressure occurs, and water rushes back into the capillaries.
How are arteries placed?
The placement of vessels on the way to the organs occurs along the shortest path to them. The vessels localized in our extremities pass with inside, since from the outside, their path would be longer.
Also, the vascular pattern is definitely related to the structure of the human skeleton. An example is that the brachial artery runs along the upper limbs, called the bone, respectively, near which it passes - the brachial artery.
By this principle, other arteries are called the radial artery - directly next to the radius, ulnar - in the vicinity of the elbow, etc.
With the help of connections between nerves and muscles, vascular networks are formed in the joints, in the systemic circle of blood circulation. That is why at the moments of movement of the joints, they constantly support blood circulation.
The functional activity of the organ affects the dimensionality of the vessel leading to it; in this case, the size of the organ does not play a role. The more important and functional organs, the more arteries lead to them.
Their placement around the organ itself is influenced exclusively by the structure of the organ.
System circle
The main task of a large circle of blood circulation is gas exchange in any organs except the lungs. It starts from the left ventricle, blood from it enters the aorta, spreading further through the body.
Components of the systemic circulation from the aorta, with all its branches, arteries of the liver, kidneys, brain, skeletal muscles and other organs. After large vessels, it continues with small vessels and veins of the above organs.
The right atrium is its final destination.
Directly from the left ventricle, arterial blood enters the vessels through the aorta, it contains most of the oxygen, and a small proportion of carbon. The blood in it is taken from the pulmonary circulation, where it is enriched with oxygen by the lungs.
The aorta is the largest vessel in the body, and consists of a main canal and many outgoing, smaller arteries leading to organs for saturation.
The arteries leading to the organs are also divided into branches and deliver oxygen directly to the tissues of certain organs.
With further branches, the vessels become smaller and smaller, eventually forming a great many capillaries, which are the smallest vessels in human body... The capillaries do not have a muscle layer, but are represented only by the inner lining of the vessel.
Many capillaries form a capillary network. They are all covered with endothelial cells, which are at a sufficient distance from each other for nutrients to penetrate into the tissue.
This promotes gas exchange between small vessels and the area between cells.
They supply oxygen and take carbon dioxide. The entire exchange of gases occurs constantly, after each contraction of the heart muscle, oxygen is delivered to the tissue cells in some part of the body, and the hydrocarbon is outflow from them.
The vessels that collect the hydrocarbon are called venules. They subsequently join into larger veins, and form one large vein... Veins large sizes form the superior and inferior vena cava, ending in the right atrium.
Features of the systemic circulation
Special differences in the systemic circulation are that the liver contains not only the hepatic vein, which removes venous blood from it, but also the portal, which in turn supplies blood to it, where the blood is purified.
After that, the blood enters the hepatic vein and is transported to the large circle. The blood in the portal vein comes from the intestines and stomach, which is why harmful products food has such a detrimental effect on the liver - they are cleansed in it.
The tissues of the kidneys and pituitary gland also have their own characteristics. Directly in the pituitary gland there is its own capillary network, which implies the division of arteries into capillaries, and their subsequent connection into venules.
After that, the venules are again divided into capillaries, then a vein is already formed, which makes the outflow of blood from the pituitary gland. With regard to the kidneys, the division of the arterial network takes place in a similar way.
How is blood circulation in the head?
One of the most complex structures of the body is blood circulation in cerebral vessels... The parts of the head are fed by the carotid artery, which divides into two branches (read). More details about
The arterial vessel enriches the face, temporal zone, mouth, nasal cavity, thyroid gland and other parts of the face.
Deep in the brain tissue, blood is supplied through the internal branch of the carotid artery. It forms a circle of Willis in the brain, along which the blood circulation of the brain takes place. Inside the brain, the artery is divided into the connective, anterior, middle, and ocular arteries. This is how most of the systemic circle is formed, which ends in the cerebral artery.
The main arteries feeding the brain are the subclavian and carotid arteries, which are connected together.
With the support of the vascular network, the brain functions with minor interruptions in the circulation of blood flows.
Small circle
The main purpose of the pulmonary circulation is the exchange of gases in the tissues that saturate the entire area of the lungs in order to enrich the already spent blood with oxygen.
The pulmonary circle of blood circulation starts from the right ventricle, where blood enters, from the right atrium, with a low oxygen concentration and a high hydrocarbon concentration.
From there, blood enters the pulmonary trunk, bypassing the valve. Further, the blood moves along the network of capillaries located throughout the volume of the lungs. Similar to the capillaries of the systemic circle, small vessels of the lung tissue produce gas exchange.
The only difference is that oxygen enters the lumen of small vessels, and not carbon dioxide, which penetrates into the cells of the alveoli. The alveoli, in turn, are enriched with oxygen with each inhalation of a person, and with exhalation, the hydrocarbon is removed from the body.
Oxygen saturates the blood, making it arterial. After which it is transported along the venules and reaches the pulmonary veins, which end in the left atrium. This explains the fact that there is arterial blood in the left atrium, and venous blood in the right atrium, and they do not mix with a healthy heart.
The lung tissue contains a double-level capillary mesh. The first is responsible for gas exchange to enrich venous blood with oxygen (connection with the pulmonary circulation), and the second maintains saturation of the lung tissues themselves (connection with the systemic circulation of blood).
In the small vessels of the heart muscle, an active exchange of gases takes place, and the blood is withdrawn into the coronary veins, which later unite and end in the right atrium. It is according to this principle that circulation in the cavities of the heart and the enrichment of the heart with nutrients occurs, this circle is also referred to as coronary. This is an additional protection of the brain from a lack of oxygen. Its components are such vessels: internal carotid arteries, the initial part of the anterior and posterior cerebral arteries, as well as the anterior and posterior connecting arteries.
Also, in pregnant women, extra circle circulation, called placental. Its main task is to maintain the baby's breathing. Its formation occurs at 1-2 months of gestation.
It begins to work in full force after the twelfth week. Since the fetal lungs are not yet functioning, oxygen enters the bloodstream through the umbilical vein of the embryo with the flow of arterial blood.
Circulatory organs. The functions of the blood are performed thanks to continuous work circulatory system. Blood circulation - this is the movement of blood through the vessels, ensuring the exchange of substances between all tissues of the body and external environment... The circulatory system includes the heart and blood vessels. The circulation of blood in the human body through a closed cardiovascular system is provided by rhythmic contractions hearts- its central organ. The vessels that carry blood from the heart to tissues and organs are called arteries and those through which blood is delivered to the heart - veins. In tissues and organs, thin arteries (arterioles) and veins (venules) are interconnected by a dense network blood capillaries.
Heart. The heart is located in chest cavity behind the sternum and surrounded by a connective tissue sheath - pericardial bag. The bag protects the heart, and the mucous secretion secreted by it reduces friction during contraction. Heart weight about 300 g, conical shape. Wide part of the heart -base- facing up and to the right, narrow - top- down and to the left. Two thirds of the heart is located on the left side of the chest cavity, and one third on the right.
The human heart, like the heart of birds and mammals, is four-chambered. It is divided by a continuous longitudinal partition into left and right halves. Each half, in turn, is subdivided into two chambers - atrium and ventricle. They communicate with each other with holes provided flap valves. There is a bicuspid valve in the left half of the heart, and a tricuspid valve in the right. The valves open only towards the ventricles and therefore allow blood to flow in only one direction: from the atria to the ventricles. Tendon threads extending from the surface and edges of the valves and attaching to the muscle protrusions of the ventricles interfere with the opening of the valve flaps towards the atria. Muscle protrusions, contracting together with the ventricles, pull the tendon threads, thereby preventing the eversion of the valve cusps towards the atria and the backflow of blood into the atria.
Two vena cava flows into the right atrium - the lower and the upper, into the left - two pulmonary veins. The pulmonary trunk (artery) departs from the right ventricle, and the aortic arch from the left. From the aorta there are two coronary (coronary) arteries that feed the heart muscle itself with blood. At the site of discharge from the ventricles of the pulmonary trunk and aorta are located semilunar valves in the form of three pockets opening towards the blood flow. They prevent blood from flowing back to the ventricles. Thus, due to the work of the leaflet and semilunar valves in the heart, blood flow is carried out only in one direction: from the atria to the ventricles, and then from them to the pulmonary trunk and aorta.
The wall of the heart consists of three layers: epicardium- external connective tissue, covered with a single layer of epithelium; myocardium- middle muscular; endocardium- internal epithelial. The muscular walls of the heart are the thinnest in the atria (2-3 mm). The muscular layer of the wall of the left ventricle is 2.5 times thicker than that of the right ventricle. The heart valve apparatus is formed by outgrowths of the inner layer of the heart.
The work of the heart and its regulation. The work of the heart is composed of rhythmically replaced each friend of cardiac cycles- periods covering one contraction and subsequent relaxation of the heart. The contraction of the heart muscle is called systole, relaxation - diastole. With a heart rate of 75 times per minute, the duration of the cardiac cycle is 0.8 s. There are three phases in the cycle: atrial contraction - 0.1 s, ventricular contraction - 0.3 s, and general relaxation (pause) of the atria and ventricles - 0.4 s, during which the leaflet valves are open and blood from the atria enters the ventricles ... The atria are in a relaxed state for 0.7 s, and the ventricles for 0.5 s. During this period of time, they manage to restore their working capacity. Consequently, the reason for the fatigue of the heart lies in the rhythmic alternation of contractions and relaxation of the myocardium.
Sequential rhythmic contractions and relaxation of the atria and ventricles and the activity of the heart valves provide a unidirectional movement of blood from the atria to the ventricles, and from the ventricles to the small and large circles of blood circulation.
With each systole, the ventricles of the heart are ejected into the aorta and pulmonary artery 65-70 ml of blood. At a heart rate of 70-75 beats per minute, the ventricles are pumped respectively over 4 -5 liters of blood. When tense physical work the pumped minute volume of blood can reach 20-30 liters.
Contractions of the heart occur as a result of periodically arising processes of excitation in the heart muscle itself. As a result, the heart muscle is capable of contractions, being isolated from the body. This property is named automation. The zone of origin of excitement, called sinoatrial node or pacemaker located in the wall of the right atrium near the confluence of the superior and inferior vena cava. From it originate the nerve pathways, along which the resulting excitement is carried out into the left atrium, and then into the ventricles. This is why the atria contract first and then the ventricles. Heart contractions are involuntary, that is, a person cannot, by volitional effort, change the frequency and strength of contractions.
Changes in the rhythm of the heart are regulated by the nervous and endocrine systems. Impulses from the sympathetic part of the autonomic nervous system, accelerate the work of the heart, and those coming from the parasympathetic slow it down. The adrenal hormone adrenaline speeds up and intensifies the activity of the heart, and acetylcholine slows down and weakens its work. The hormone also increases heart rate thyroid gland thyroxine.
Arteries. Blood flow in arterial system. Arteries contain only 10-15% of the circulating blood volume. Their main functions are: fast delivery of blood to organs and tissues, as well as ensuring the high pressure required to maintain a continuous flow of blood through the capillaries.
The structure of the arteries corresponds to their function. The walls of both large arteries and small arterioles consist of three layers. Their cavity is lined unilamellar epithelium -endothelium. Middle layer represented by smooth muscles capable of expanding and narrowing the lumen of blood vessels. The outer layer is the fibrous membrane. There are many elastic fibers in the wall of the arteries. The diameter of the aorta is 25 mm, arteries - 4 mm, arterioles - 0.03 mm. The speed of blood movement in large arteries reaches 50 cm / s.
The blood pressure in the arterial system is pulsating. Normally, in the human aorta, it is greatest at the time of heart systole and is equal to 120 mm Hg. Art., the smallest - at the time of diastole - 80 mm Hg. Art. Despite the portioned flow of blood into the arteries, it moves non-stop through the vessels due to the elasticity of the arterial walls and their ability to change the diameter of the vascular lumen. Periodic jerky expansion of the walls of the arteries, synchronous with the contractions of the heart, is called pulse. The pulse can be determined on the arteries lying superficially on the bones (radial, temporal arteries). Have healthy person rhythmic pulse - 60-80 beats per minute. For some diseases in humans heartbeat disturbed (arrhythmia).
Capillaries. Blood flow in the capillaries. Capillaries are the thinnest (0.005-0.007 mm in diameter) and shortest (0.5-1.1 mm) blood vessels, consisting of a unilamellar epithelium. They are located in the intercellular spaces, closely adjacent to the cells of tissues and organs. The total number of capillaries is enormous. The total length of all capillaries in the human body is about 100 thousand km, and their total surface is about 1.5 thousand hectares. On this giant surface, about 250 ml of blood is spread in a layer 0.007 mm thick (since human capillaries contain about 5% of the total blood volume). The small thickness of this layer, its close contact with the cells of organs and tissues, a low blood flow rate (0.5-1.0 mm / 's) provide the possibility of a rapid exchange of substances between the blood of the capillaries and the intercellular fluid. There are pores in the wall of the capillaries through which water and inorganic substances(glucose, oxygen, etc.) can easily pass from blood plasma into tissue fluid at the arterial end of the capillary, where the blood pressure is 30-35 mm Hg. Art.
Vienna. Blood flow in the veins. The blood, passing through the capillaries and enriched with carbon dioxide and other waste products, enters venules, which, merging, form more and more large venous vessels. They carry blood to the heart due to the action of several factors: 1) at the beginning of the venous system of the systemic circulation, the pressure is approximately 15 mm Hg. Art., and in the right atrium in the diastole phase, it is equal to zero. This difference facilitates the flow of blood from the veins into the right atrium; 2) the veins have semilunar valves, therefore, contractions of the skeletal muscles, leading to compression of the veins, cause an active pumping of blood towards the heart; 3) when inhaling, the negative pressure in the chest cavity increases, which promotes the outflow of blood from the large veins to the heart.
Diameter of the largest hollow veins is 30 mm, veins--5 mm, venul- 0.02 mm. The veins contain about 65-70% of the total circulating blood volume. They are thin, easily stretchable, as they have a poorly developed muscle layer and a small amount of elastic fibers. By gravity, blood in the veins lower limbs tends to stagnate, leading to varicose veins. The velocity of blood flow in the veins is 20 cm / s or less, while the blood pressure is low or even negative. Veins, unlike arteries, are superficial.
Large and small circles of blood circulation. V the human body, blood moves in two circles of blood circulation - large (trunk) and small (pulmonary).
A large circle of blood circulation begins in the left ventricle, from which arterial blood is ejected into the largest artery in diameter - aorta. The aorta makes an arc to the left and then runs along the spine, branching into smaller arteries that carry blood to the organs. In the organs, the arteries branch into smaller vessels - arterioles, who go online capillaries, penetrating tissues and delivering oxygen to them and nutrients... Venous blood is collected through the veins in two large vessels - upper and inferior vena cava, which pour it into the right atrium.
Small circle of blood circulation begins in the right ventricle, from where the arterial pulmonary trunk exits, which is divided into flowering arteries, carrying blood to the lungs. In the lungs, large arteries branch into smaller arterioles, passing into a network of capillaries, densely encircling the walls of the alveoli, where gases are exchanged. Oxygenated arterial blood flows through the pulmonary veins into the left atrium. Thus, venous blood flows in the arteries of the pulmonary circulation, and arterial blood flows in the veins.
Not all blood volume in the body circulates evenly. Much of the blood is in blood depots- liver, spleen, lungs, subcutaneous vascular plexuses. The importance of blood depots lies in the ability to quickly provide oxygen to tissues and organs in emergency situations.
Nervous and humoral regulation movement of blood. The blood in the body is distributed between the organs depending on their activity. The working organ is intensively supplied with blood by reducing the blood supply to other areas of the body. The vasoconstriction and dilation, due to which blood is redistributed between the organs of the human body, occurs as a result of contraction and relaxation of smooth muscles located in the walls of blood vessels. Nerve fibers from two divisions of the autonomic nervous system are suitable for them. Excitation of the sympathetic nerves causes a narrowing of the lumen of the vessels; arousal parasympathetic not ditches has the opposite effect. The adrenal hormone adrenaline has a vasoconstrictor effect (except for the vessels of the heart and brain) and increases blood pressure.
Alcohol and nicotine have a harmful effect on the work of the cardiovascular system. Under the influence of alcohol, the strength and heart rate, tone and filling of blood vessels change. Nicotine causes vasospasm. This leads to an increase blood pressure... When smoking, the blood constantly contains carboxyhemoglobin, which impairs the supply of oxygen to tissues, including the heart.
In 1623, died Pietro Sarpi, a well-educated Venetian monk, whose share of participation is in the opening of the venous valves. Among his books and manuscripts, they found a copy of an essay on the movement of the heart and blood, published in Frankfurt only five years later. It was the work of William Harvey, a student of Fabrice.
Harvey is one of the outstanding researchers of the human body. He contributed a lot to the fact that the medical school in Padua acquired such a resounding fame in Europe. In the courtyard of the University of Padua, you can still see the coat of arms of Harvey, fortified above the door to the hall in which Fabrizio read his lectures: two Aesculapius snakes wrapped around a burning candle. This burning candle, chosen by Harvey as a symbol, depicted life devoured by flames, but nonetheless shining.
William Harvey (1578-1657)
Harvey discovered a large circle of blood circulation, through which blood from the heart passes through the arteries to the organs, and from the organs through the veins goes back to the heart - a fact that nowadays is taken for granted for everyone who knows at least a little about the human body and its structure. However, for that time, this was a discovery of extraordinary importance. Harvey is as important to physiology as Vesalius is to anatomy. He was greeted with the same hostility as Vesalius, and just like Vesalius, gained immortality. But having lived to a more advanced age than the great anatomist, Harvey turned out to be happier than him - he died in the light of glory.
Harvey also had to contend with the traditional view, expressed by Galen, that arteries supposedly contain little blood, but a lot of air, while veins are filled with blood.
Every person of our time has a question: how could it be assumed that the arteries do not contain blood? Indeed, for any injury that affected the arteries, a stream of blood gushed from the vessel. The sacrifices and slaughter of animals also indicated that blood flowed in the arteries, and even a lot of blood. However, we must not forget that scientific views were then determined by observation data on the corpses of dissected animals and rarely on human corpses. In a dead body, as every first-year medical student can attest, the arteries are narrowed and nearly bloodless, while the veins are thick and full of blood. This bloodlessness of the arteries, which comes only with the last beat of the pulse, prevented correct understanding their meanings, and therefore nothing was known about blood circulation. It was believed that blood is formed in the liver - in this powerful and blood-rich organ; through a large vena cava, the thickness of which could not help but catch the eye, it enters the heart, passes through the thinnest holes - pores (which, however, no one has ever seen) - in the heart septum from the right heart chamber to the left and from here goes to the organs ... In the organs, it was taught at the time, this blood is consumed and therefore the liver must constantly produce new blood.
As early as 1315, Mondino de Luzzi suspected that such a view was not true and that blood was also flowing from the heart into the lungs. But his guess was very vague, and it took over two hundred years to say a clear and precise word about it. It was said by Servetus, who deserves to say something about him.
Miguel Servet (1511-1553)
Miguel Servet (actually Serveto) was born in 1511 in Villanova in Spain; his mother was from France. He received general education in Saragossa, law education - in Toulouse, France (his father was a notary). From Spain, a country over which the smoke of the fires of the Inquisition spread, he got to a country where it was easier to breathe. In Toulouse, the mind of a seventeen-year-old boy was filled with doubts. Here he had the opportunity to read Melanchthon and other authors who rebelled against the spirit of the Middle Ages. For hours Servetus sat with like-minded people and peers, discussing individual words and phrases, doctrines and different interpretations bible. He saw the difference between what Christ taught and what the overlapping sophistry and despotic intolerance turned into this teaching.
He was offered the post of secretary to the confessor of Charles V, which he willingly accepted. Thus, together with the court, he visited Germany and Italy, witnessed the celebrations and historical events and met with the great reformers - with Melanchthon, Martin Bucer, and later with Luther, who made a great impression on the fiery youth. Despite this, Servetus became neither a Protestant nor a Lutheran, and disagreement with dogma catholic church did not lead him to the reformation. Striving for something completely different, he read the Bible, studied the history of the emergence of Christianity and its unfalsified sources, trying to achieve the unity of faith and science. Servetus did not foresee the dangers to which this might lead.
Reflections and doubts closed his way anywhere: he was a heretic for both the Catholic Church and the reformers. Everywhere he met ridicule and hatred. Of course, there was no place for such a person at the imperial court, and even more so he could not remain the secretary of the emperor's confessor. Servetus chose a restless path, never to leave it again. At the age of twenty, he published an essay in which he denied the trinity of God. Then Bucer said: "This atheist should have been shredded to pieces and ripped out of his body." But he did not have to see the fulfillment of his desire: he died in 1551 in Cambridge and was buried in the main cathedral. Later, Mary Stuart ordered that his remains be removed from the coffin and burned: for her, he was a great heretic.
Servetus printed the aforementioned work on the Trinity at his own expense, which swallowed up all his savings. Relatives abandoned him, friends disowned him, so he was glad when he finally got a job under an assumed name as a proofreader for a book printer in Lyon. The latter, pleasantly impressed by his new employee's good knowledge of Latin, commissioned him to write a book about the Earth, based on her theory of Ptolemy. This is how a hugely successful work was published, which we would call comparative geography. Thanks to this book, Servetus met and became friends with the physician-in-chief of the Duke of Lorraine, Dr. Champier. This Dr. Champier was interested in books and was the author of several books himself. He helped Servetus find his true vocation - medicine and forced him to study in Paris, probably giving him funds for this.
A stay in Paris allowed Servetus to meet the dictator of the new doctrine - Johann Calvin, who was two years older than him. Anyone who disagreed with his views, Calvin punished with hatred and persecution. Servetus later also became his victim.
After completing his medical education, Servetus did not long study medicine, which could provide him with a piece of bread, peace of mind, confidence in the future and universal respect. For some time he practiced in Charlier, located in the fertile Loire Valley, but, fleeing persecution, he was forced to return to the proofreader in Lyon. Then fate extended a saving hand to him: none other than the Archbishop of Vienne took the heretic to him as a physician, thereby providing him with protection and conditions for a quiet work.
For twelve years Servetus lived quietly in the archbishop's palace. But peace was only outwardly: the great thinker and skeptic was not abandoned by inner anxiety, a secure life could not extinguish the inner fire. He continued to ponder and search. Inner power, and, perhaps, only gullibility prompted him to tell his thoughts to the one in whom they should have caused the greatest hatred, namely Calvin. Preacher and head new faith, of his faith, was sitting at that time in Geneva, ordering to burn everyone who contradicted him.
It was the most dangerous, or rather, suicidal step - to send the manuscripts to Geneva in order to initiate a man like Calvin into what a man like Servetus thinks about God and the church. But not only that: Servetus sent Calvin also his own work, his main work with its appendix, in which all his errors were clearly and thoroughly listed. Only a naive person could think that it was only about scientific disagreements, about business discussion... Servetus, pointing out all the mistakes of Calvin, hurt him painfully and irritated him to the limit. This was the beginning of the tragic end of Servetus, although seven more years passed before the flames closed over his head. In order to finish the matter in peace, Servetus wrote to Calvin: “Let's go in different ways, give me back my manuscripts and goodbye. " Calvin, in one of the letters to his like-minded fellow, the famous iconoclast Farel, whom he managed to win over to his side, says: "If Servetus ever visits my city, I will not let him out alive."
The work, part of which Servetus sent to Calvin, was published in 1553, ten years after the first edition of Vesalius' anatomy. One and the same era gave birth to both of these books, but how fundamentally different they are in their content! "Fabrika" by Vesalius is the doctrine of the structure, corrected as a result of the author's own observations. human body, denial of galenic anatomy. Servetus's work is a theological book. He called it "Cristianismi restitutio ...". The entire title, in accordance with the tradition of that era, is very long and reads as follows: "The restoration of Christianity, or the appeal to the entire apostolic church to return to its own beginnings, after the knowledge of God, faith in Christ our redeemer, regeneration, baptism, and also eating the food of the Lord, and after the kingdom of heaven finally opens up for us again, deliverance from godless Babylon will be granted, and the human enemy with his own will be destroyed. "
This work was polemical, written in refutation of the dogmatic teaching of the church; it was secretly printed in Vienne, knowingly doomed to be banned and burned. However, three copies still escaped destruction; one of them is kept in the Vienna National Library. For all its attacks on dogma, the book professes humility. It represents a new attempt by Servetus to unite faith with science, to adapt the human to the inexplicable, the divine, or to make the divine, that is, what is set forth in the Bible, accessible through scientific interpretation. In this work about the restoration of Christianity, quite unexpectedly, a very remarkable passage is encountered: “In order to comprehend this, one must first understand how the life spirit is produced ... The life spirit originates in the left heart ventricle; how there is a mixing of the air entering them with blood coming from the right heart ventricle. This path of blood, however, does not at all run through the septum of the heart, as is commonly thought, and blood is chased in an extremely skillful way from the right heart ventricle to the lungs ... soot ”(here carbon dioxide is meant). "After the blood is well mixed through the breath of the lungs, it is finally drawn back into the left heart ventricle."
How Servetus came to this discovery - by observation on animals or on humans - is unknown: it is only beyond doubt that he was the first to clearly recognize and describe the pulmonary circulation, or the so-called pulmonary circulation, that is, the path of blood from the right side of the heart to the lungs and from there back to left side hearts. But extremely important discovery thanks to which the idea of Galen about the transition of blood from the right ventricle to the left through the cardiac septum went into the realm of myths, from where it came, only a few doctors of that era paid attention. This, obviously, should be attributed to the fact that Servetus presented his discovery not in a medical, but in a theological essay, moreover, in one that was diligently and very successfully searched for and destroyed by the servants of the Inquisition.
Servetus's characteristic isolation from the world, a complete lack of understanding of the seriousness of the situation led to the fact that when traveling to Italy, he stopped in Geneva. Did he assume he would drive through the city unnoticed, or did he think that Calvin's anger had long since cooled down?
Here he was captured and thrown into prison and could no longer expect mercy. He wrote to Calvin, asking him for more humane conditions of imprisonment, but he did not know pity. “Remember,” read the answer, “how sixteen years ago in Paris I tried to persuade you to our Lord! If you had come to us then, I would have tried to reconcile you with all the good servants of God. You hounded and blasphemed me. Now you can pray for the mercy of the Lord, whom you denounced, wishing to overthrow the three beings embodied in him - the trinity. "
The verdict of the four highest ecclesiastical authorities then existing in Switzerland, of course, coincided with the verdict of Calvin: he proclaimed death by burning and on October 27, 1553 was carried out. It was a painful death, but Servetus refused to renounce his beliefs, which would have given him the opportunity to achieve a milder execution.
However, in order for the pulmonary circulation discovered by Servetus to become the common property of medicine, it had to be rediscovered. This second discovery was made a few years after the death of Servet Realdo Colombo, who headed the department in Padua, which was previously in charge of Vesalius.
William Harvey was born in 1578 at Folkestone. He attended an introductory course in medicine at the Cambridge College of Cayus, and in Padua, the center of attraction for all doctors, he received a medical education corresponding to the level of knowledge of that time. While still a student, Harvey was distinguished by the sharpness of his judgments and critical and skeptical remarks. In 1602 he received the title of doctor. His teacher Fabrizio could be proud of a student who, just like him, was interested in all the big and small secrets of the human body and even more than the teacher himself did not want to believe what the ancients taught. Everything must be investigated and rediscovered, - such was the opinion of Harvey.
Returning to England, Harvey became professor of surgery, anatomy and physiology in London. He was the physician-in-chief of Kings James I and Charles I, accompanied them on their travels, as well as during civil war 1642 Harvey accompanied the court on his escape to Oxford. But here, too, the war came with all its unrest, and Harvey had to give up all his posts, which, however, he did willingly, since he wanted only one thing: to spend the rest of his life in peace and tranquility, doing books and research.
A brave and elegant man in his youth, in old age, Harvey became calm and modest, but he was always an outstanding nature. He died at the age of 79 as a level-headed old man who looked at the world with the same skepticism that he once looked at the theory of Galen or Avicenna.
In the last years of his life, Harvey wrote an extensive work on embryological research. It was in this book on the development of animals that he wrote the famous words - "ornne vivum ex ovo" ("all living things from an egg"), which captured the discovery that has dominated biology since then in the same formulation.
But it was not this book that brought him great fame, but another, much smaller in volume, a book about the movement of the heart and blood: "Exercitatio anatomica de motu cordis et sanguinis in animalibus" ("Anatomical study of the movement of the heart and blood in animals"). It was published in 1628 and sparked a passionate and fierce debate. A new and too unusual discovery could not fail to excite the minds. Harvey was able to discover through numerous experiments, when he studied the still beating heart and breathing lungs of animals in order to discover the truth, a large circle of blood circulation.
Harvey made his great discovery back in 1616, because even then in one of his lectures at the College of Phisicians in London, he spoke about the fact that blood “circulates” in the body. However, for many years he continued to search and accumulate proof after proof and only twelve years later published the results of his hard work.
Of course, Harvey described a lot of what was already known, but mainly what he believed pointed to the right path in the search for truth. And yet he owes the greatest merit to the knowledge and clarification of the blood circulation as a whole, although he did not notice one part of the circulatory system, namely the capillary system - a complex of the finest, hair-like vessels that are the end of the arteries and the beginning of the veins.
Jean Rioland Jr., professor of anatomy in Paris, head of the medical school and royal physician, led the fight against Harvey. This turned out to be serious opposition, since Riolan was, indeed, a major anatomist and an outstanding scientist who enjoyed great prestige.
But gradually opponents, even Riolan himself, fell silent and recognized that Harvey had managed to make one of the greatest discoveries concerning the human body, and that the doctrine of the human body had entered a new era.
The most fiercely contested Harvey's discovery was the Paris medical faculty. Even a hundred years later, the conservatism of the doctors of this faculty was still the subject of ridicule by Rabelais and Montaigne. In contrast to the Montpellier school, with its freer atmosphere, the faculty, in its rigid adherence to tradition, adhered unwaveringly to the teachings of Galen. What could these gentlemen, importantly speaking in their precious uniforms, know about the calls of their contemporary Descartes to replace the principle of authority with the dominance of the human mind!
The debate about circulation has gone far beyond the specialist circles. Moliere also took part in fierce verbal battles, who more than once turned the severity of his ridicule against the narrow-mindedness and arrogance of doctors of that era. So, in "The Imaginary Sick", the newly minted Doctor Thomas Diafuarus entrusts the role to the servant Toinette: the role contains a thesis composed by him, directed against the supporters of the doctrine of blood circulation! Even if he was confident of the approval of this thesis by the Parisian medical faculty, he could no less be sure of the crushing, destructive laughter of the public.
The circulation, as Harvey described it, is the true circulation of the blood in the body. With the contraction of the heart ventricles, blood from the left ventricle is pushed into the main artery - the aorta; through it and its branches it penetrates everywhere - in the leg, arm, head, in any part of the body, delivering vital oxygen there. Harvey did not know that in the organs of the body, blood vessels branch out into capillaries, but he correctly pointed out that blood then collects again, flows through the veins back to the heart, and flows through the vena cava into the right atrium. From there, the blood enters the right ventricle and, with the contraction of the ventricles, is directed through the pulmonary artery, extending from the right ventricle, into the lungs, where it is supplied with fresh oxygen - this is a small circle of blood circulation, opened by Servetus. Having received fresh oxygen in the lungs, blood flows through the large pulmonary vein into the left atrium, from where it enters the left ventricle. After that, the systemic circulation is repeated. You just need to remember that arteries are the vessels that lead blood away from the heart (even if they, like the pulmonary artery, contain venous blood), and veins are the vessels leading to the heart (even if they, like the pulmonary vein, contain arterial blood).
Systole is a contraction of the heart; atrial systole is much weaker than the systole of the cardiac ventricles. Expansion of the heart is called diastole. The movement of the heart covers both the left and right sides. It begins with atrial systole, from where blood is chased into the ventricles; followed by systole wish daughters, and blood is pushed into two large arteries - into the aorta, through which it enters all areas of the body (systemic circulation), and the pulmonary artery, through which it passes into the lungs (small, or pulmonary, circulation). This is followed by a pause, during which the ventricles and atria are dilated. All this was basically established by Harvey.
At the beginning of his not very voluminous book, the author talks about what exactly prompted him to this essay: “When I first turned all my thoughts and desires to observations based on vivisections (to the extent that I had to of my own contemplations, and not from books and manuscripts to recognize the meaning and benefits of heart movements in living beings, I found that this question is very complex and full of mysteries at every step. Namely, I could not make out exactly how systole and diastole occurs. After day after day, exerting more and more strength to achieve greater accuracy and thoroughness, I studied a large number of various living animals and collected data from numerous observations, I finally came to the conclusion that I had hit the trail of interest to me and managed to get out. from this labyrinth, and at the same time, as he wanted, he recognized the movement and purpose of the heart and arteries. "
The extent to which Harvey was entitled to assert this is evidenced by his strikingly accurate description of the movement of the heart and blood: “First of all, on all animals, while they are still alive, chest observe that the heart first makes a movement, and then rests ... Three moments can be observed in movement: first, the heart rises and raises its top in such a way that at this moment it knocks on the chest and these beats are felt outside; secondly, it shrinks from all sides, somewhat more from the side, so that it decreases in volume, somewhat stretches and wrinkles; thirdly, if you take a heart in your hand at the moment when it makes a movement, it hardens. Hence it became clear that the movement of the heart consists in general (to a certain extent) tension and all-round compression, respectively, the pull of all its fibers. These observations are consistent with the conclusion that the heart, at the moment when it makes a movement and contracts, narrows in the ventricles and squeezes out the blood contained in them. Hence, there arises an obvious contradiction to the generally accepted belief that at the moment when the heart strikes the chest, the ventricles of the heart expand, filling at the same time with blood, while one can be convinced that the situation should be exactly the opposite, namely, that the heart is emptied at the moment of contraction ".
Reading Harvey's book, one has to constantly be amazed at the accuracy of the description and the sequence of conclusions: “So nature, which does nothing for no reason, did not provide a heart for such a living being that does not need it and did not create a heart before it acquired meaning; nature achieves perfection in each of its manifestations by the fact that during the formation of any living creature, it goes through the stages of formation (if I may say so), common to all living beings: an egg, a worm, an embryo. " In this conclusion, one can recognize an embryologist - a researcher engaged in the study of the development of the human and animal organism, who in these remarks clearly indicates the stage of development of the embryo in the mother's womb.
Harvey is undoubtedly one of the outstanding pioneers of human history, a researcher who opened a new era of physiology. Many later discoveries in this area were significant and even extremely significant, but nothing was more difficult than the first step, that first act that crushed the edifice of error in order to erect the edifice of truth.
Of course, there were still a few links missing from Harvey's system. First of all, there was a lack of a connecting part between the arterial system and the vein system. How does blood, going from the heart through the large and small arteries to all parts of the organs, finally enter the veins, and from there back to the heart, in order to then store new oxygen in the lungs? Where is the transition from arteries to veins? This important part of the circulatory system, namely the connection of arteries with veins, was discovered by Marcello Malpighi of Crevalcore near Bologna: in 1661, in his book on the anatomical study of the lungs, he described hair vessels, i.e., capillary circulation.
Malpighi studied in detail the pulmonary vesicles on frogs and found that the thinnest bronchioles end in pulmonary vesicles, which are surrounded by blood vessels. He also noticed that the thinnest arteries are located next to the thinnest veins, one capillary mesh is next to the other, and he correctly assumed that there is no air in the blood vessels. He considered it possible to make this message to the public, since even earlier he acquainted her with his discovery of a capillary network in the mesentery of frog intestines. The walls of the hair vessels are so thin that oxygen easily penetrates from them to the tissue cells; oxygen-poor blood is then directed to the heart.
Thus, the most important stage of blood circulation was discovered, which determined the completeness of this system, and no one could deny that blood circulation does not occur as described by Harvey. Harvey died several years before the discovery of Malpighi. He did not happen to witness the complete triumph of his teaching.
The opening of the capillaries was preceded by the opening of the pulmonary vesicles. Here is what Malpighi writes to his friend Borelli: “Every day, doing autopsies with increasing diligence, I recently studied with special care the structure and function of the lungs, about which, it seemed to me, there is still a rather vague idea. Now I want to inform you of the results of my research, so that with your eyes, so experienced in the affairs of anatomy, you could separate the right from the wrong and effectively use my discoveries ... Through diligent research, I discovered that the entire mass of the lungs that hang on the vessels emanating from them consists of from very thin and delicate films. These films, sometimes straining, then wrinkling, form many bubbles, similar to the honeycomb of a hive. Their location is such that they are directly connected both with each other and with the windpipe, and form an interconnected film as a whole. This is best seen on lungs taken from a living animal, especially at their lower end, numerous small bubbles swollen from air can be clearly seen. The same thing, although not so clearly, can be recognized in a lung cut in the middle and devoid of air. In direct light, on the surface of the lungs in a loose state, a wonderful network is noticeable, which seems to be closely connected with individual bubbles; the same can be seen on the cut lung and from the inside, although not so clearly.
Usually the lungs vary in shape and location. There are two main parts, between which is the mediastinum (Mediastinum); each of these parts consists of two in humans, and in animals from several subdivisions. I myself have discovered the most wonderful and most complicated division. The total mass of the lungs consists of very small lobules, surrounded by a special kind of film and equipped with their own vessels, formed from the processes of the windpipe.
To distinguish these lobules, one should hold the semi-inflated lung against the light, and then the gaps clearly appear; when air is blown through the windpipe, the lobules enveloped in a special film can be separated by small sections from the vessels that touch them. This is achieved through very careful preparation.
As far as lung function is concerned, I know that many things that old people take for granted are still highly questionable, especially blood cooling, which is traditionally considered the main function of the lungs; this view is based on the assumption that there is a warmth ascending from the heart, seeking a way out. I, however, for reasons which I will say below, consider it most likely that the lungs are designed by nature to mix the mass of blood. As for blood, I do not believe that it consisted of four commonly assumed fluids - both galenic substances, blood itself and saliva, but I am of the opinion that the entire mass of blood, continuously flowing through the veins and arteries and consisting of small particles, is composed from two very similar liquids - whitish, which is usually called serum, and reddish ... "
During the publication of his work, Malpighi came to Bologna a second time, where he had already arrived at the age of twenty-eight as a professor. He did not meet with sympathy from the faculty, which immediately opposed the new doctrine in the most harsh way. After all, what he proclaimed was a medical revolution, an uprising against Galen; all united against this, and the old people began a real persecution of the youth. This prevented Malpighi from working calmly, and he changed the department in Bologna to the department in Messina, believing that he would find other conditions for teaching there. But he was delusional, for even there he was pursued by hatred and envy. In the end, after four years, he decided that Bologna was still better, and returned there. However, in Bologna, a turning point in mood had not yet come, although the name of Malpighi was already widely known abroad.
The same thing happened with Malpighi as with many others, both before him and after him: he became a prophet, not recognized in his own country. The famous Royal Society of England, the Royal Society, elected him a member, but the Bologna professors did not consider it necessary to take this into account and continued to persecute Malpighi with unremitting stubbornness. Even in the audience unworthy scenes were played out. One day during a lecture, one of his opponents appeared and began to demand that the students leave the audience; everything, they say, that Malpighi teaches is absurdity, his dissections are devoid of any value, only fools can work in this way. There was also a worse case. Two disguised faculty professors - anatomists Muni and Sbaralya - came to the scientist's country house, accompanied by a crowd of people also wearing masks. They launched a devastating attack: Malpighi, then a 61-year-old man, was beaten and his household belongings destroyed. This method, apparently, did not represent anything unusual in Italy of that era, since Berengario de Carpi himself somehow thoroughly destroyed the apartment of his scientific opponent. With Malpighi, that was enough. He left Bologna again and went to Rome. Here he became the pope's physician and spent the rest of his life serenely.
The discovery of Malpighi, dating back to 1661, could not have been made earlier, since it was impossible to examine the finest blood vessels, much thinner than human hair, with the naked eye: this required a highly magnifying system of loupes, which appeared only at the beginning of the 17th century ... The first microscope in its simplest form was apparently made with a combination of lenses around 1600 by Zachary Jansen of Meddelburg in Holland. Anthony van Leeuwenhoek, this nugget, considered the founder of scientific microscopy, in particular microscopic anatomy, has been performing microscopic studies since 1673 with the help of highly magnifying lenses he made himself.
In 1675, Leeuwenhoek discovered ciliates - a living world in a drop of water from a puddle. He died in 1723 at a very old age, leaving behind 419 microscopes, with which he achieved a magnification of up to 270 times. He never sold a single instrument. Leeuwenhoek was the first to see the transverse striation of the muscles that serve for movement, the first was able to accurately describe the skin scales and internal pigment deposits, as well as the reticular weave of the heart muscles. Already after Jan Ham, as a student in Leiden, discovered the "seed gum", Leeuwenhoek was able to prove the presence of seed cells in all species of animals.
Malpighi first discovered and red blood cells in blood vessels human mesentery, which was soon confirmed by Levenguk, but already after in 1658 these little bodies in the blood vessels were noticed by Jan Swammerdam.
Malpighi, who should be considered an outstanding researcher in the field of natural science, finally resolved the issue of blood circulation. Three spirits, which according to previous ideas were in blood vessels, were expelled in order to give way to a large "spirit" - a single blood moving in a closed circle, returning to its starting point and making a cycle again - and so on until the end of life. The forces that compel the blood to complete this cycle were already clearly known.
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