The human heart is a 4-chamber muscular hollow organ that receives venous blood from all organs and tissues and drives out fresh, oxygenated blood in the arteries. Heart chambers - 2 atria and 2 ventricles. For brevity, they are called, for example, in decoding ECG, LV and RV, and atria - respectively, LP and PP.
General information
The left 2 chambers together comprise the left or arterial heart - by the property of the blood contained in them; accordingly, the right half is a venous or right heart. Contraction of the heart muscle - systole, relaxation - diastole. Atria are chambers that receive blood, and ventricles bleed blood into the arteries.
Between all cameras there are partitions. Thanks to them, the blood of veins and arteries in the heart does not mix. In each half of the heart, chambers communicate with each other due to the presence of heart valves (atrioventricular openings). Through these openings, blood flows from them into the ventricular cavity during atrial systole. Arteries and veins of the heart have their own characteristics of structure and work.
The venous circulatory system as a whole
Vienna - a vessel that promotes blood from organs to the heart, this blood is saturated after washing the organs with carbon dioxide, in contrast to the arterial, which is saturated with oxygen.
Blood is collected in the veins from the capillaries, which are becoming larger and larger, moving in increasing caliber into venules, then into veins, and finally form a vena cava.
The venous network is an integral part of the cardiovascular system, and phlebology deals with it. The largest veins of the network are the vena cava (superior and inferior).
Blood flows to the upper vena cava of the upper body - the shoulder girdle, head, neck (lungs do not enter here). And on the lower side, on the legs and abdominal organs. All this forms a large circle of blood circulation. Hollow veins of the heart are the largest veins of a large circle in which the heart itself serves as the main pump.
The portal vein flows into the PP and from there into the pancreas. Further, blood from the heart from a vein enters the pulmonary artery and is sent to the lungs in order to be saturated with oxygen.
On average, blood throughout the venous network of the great circle passes in 23-27 seconds, although its speed is slower compared to arteries.
The veins experience a lot of stress because the blood is pushed by the veins here, overcoming the force of gravity. Venous blood, falling into the right atrium, goes into the right ventricle and from there into the pulmonary artery and into the lungs. Here it is cleaned, oxygenation occurs, and it turns into arterial.
Fresh pure blood flows through 4 pulmonary veins into the left atrium, LV, and the aorta. From here it is already spreading throughout the body. The cycle repeats again. The path of blood flow from the pancreas to the pulmonary artery, then to the lungs and again to the left ventricle, is called the pulmonary circulation or pulmonary.
Venous circulation of the heart
The main difference between the veins of the heart is that they open directly inside the heart, into its cavity. They are located on the surface of the muscle of the heart, and inside the myocardium (intramuscular veins), along the muscle bundles. There are more in the right heart than in the left half.
The heart veins are 7 main:
- coronary sinus;
- front veins;
- posterior, middle, oblique and large veins;
- small veins.
The coronary sinus is the largest, it opens directly in the PP. Its caliber is 10-12 mm, its length is from 1.5 to 5.8 cm. It is topographically below the portal inferior vein in the coronary sulcus on the left (the coronary sulcus separates the atria and ventricles). 3 veins flow into it: the middle vein of the heart, the oblique vein of the LP and the posterior vein of the LV.
The middle is located in the posterior interventricular sulcus and begins on the posterior surface of the heart near its apex. It flows into the coronary sinus on the right side after it collects blood from the posterior wall of both ventricles.
The oblique vein of the LP begins on its posterior wall, goes down diagonally to the right and also enters the coronary sinus.
The posterior - LV - starts from it, at the apex of the LV heart and ends in the coronary sinus. Thus, it turns out that the coronary sinus is the largest collector in the network of coronary vessels. It collects waste blood from the ventricles and partly the atria. It is generally accepted that the coronary sinus is a continuation of the large vein.
The large vein is a collector of small veins of the anterior walls of both ventricles, the interventricular septum, and the veins of the left edge of the heart.
Then it leaves the apex of the heart muscle on its anterior surface, passes through the interventricular sulcus, passes into the coronal and goes around the left edge of the heart, turning into the coronary sinus.
The anterior veins are located on the anterior surface of the pancreas and flow into the PP. They collect blood from the anterior wall of the pancreas.
Small veins also flow into the PP after collecting blood from the walls of the heart. Venous blood flow significantly exceeds arterial.
There are many veins in such a relatively small organ, but they are all the smallest in the body. They can collect blood only on its wall sections.
Venous nets
The veins of the heart have the form of grids that are located in different layers of the heart muscle. These nets are created by dense plexuses of venules. Anastomosing myocardial veins are clearly along the muscle bundles.
In general, networks of plexuses are localized under the endocardium and inside it, inside the myocardium, inside the epicardium, and the most powerful one is located under the epicardium. The veins of the heart are usually not associated with the location of the arteries, they are single.
In the interventricular septum, there are separately 2 more powerful venous bundles. They are formed in the anterior and posterior upper divisions of the specified septum on its border with the atria. These are the most important venous collectors of the heart, collecting blood from the legs of the bundle of His and from the septum of the ventricles. These are the main components of a conductive system.
Venous outflow of the heart
There are 2 types of venous outflow. The first type - they talk about it when the development of the magna vein (large vein) prevails - 44.2%. Blood flows from the ventricles along it. The second type of outflow is with the advantage of the system of the anterior veins of the heart (42.5%), through which blood is removed not only from the entire pancreas, but also part of the left ventricle of the heart. But in any case, as you can see, the blood supply to the heart does not suffer. There are many anastomoses between the leading vessels.
Arteries of the heart
The heart receives arterial blood, usually from two coronary (coronary) arteries - the left and right. The latter originates from the aortic bulb, their appearance is similar to the crown, which is why their other name - coronal. They supply blood to all the walls of the heart. For example, the left coronary artery supplies blood to the LV, LV, part of the anterior pancreatic wall, 70% of the interventricular septum, and the anterior papillary muscle of the LV.
What are papillary muscles and are they really important? Papillary muscles have another name - papillary. They are outgrowths in the endocardium and protrude directly into the cavity of the ventricles. Together with the chords of the apex, they help the unidirectional movement of blood. Arteries also anastomose with each other. The right artery is inclined to the right, to the ear of the right atrium. It supplies the wall sections of the pancreas and the pancreas, the papillary muscles of the left ventricle, the sinus node (pacemaker), part of the interventricular septum.
Atrial nodes are the conduction system of the heart. Its largest branch is the posterior interventricular branch, located in the groove of the same name and descends to the myocardial apex.
The left coronary artery is thicker, passes between the ear of the LP and the pulmonary trunk. It is divided into the anterior interventricular and envelope branches. The envelope actually continues the main trunk and bends around the left heart along the coronal groove. Further, on its posterior surface, it mates with the right coronary artery. In the layers of the myocardium, the vessels go along the muscle fibers.
Intraorgan arteries of the heart
These are the branches of the main coronary arteries and their large branches, are called ramuses. They are directed directly to the 4 chambers of the heart: the branches of the atria and their ears, the branches of the ventricles, septal branches - front and rear. Penetrating into the thickness of the myocardium, they actively branch further, according to the number of its layers, recalling the structure of venous networks: first in the outer layer, then in the middle (in the ventricles) and, finally, in the inner - endocardial, and then penetrate into the papillary muscles ( aa.papillares) and even in heart valves. Their course also corresponds to muscle bundles.
All of them anastomose with each other. Anastomoses and collaterals are very important in that it is thanks to them that blood flow is restored in ischemic areas, i.e. with myocardial infarction.