Small and large circulatory system: circuits. Small and large circle of blood circulation rights

The most complex circulatory system possessmammals. It is a closed system that includes two circles of circulation. Energetically it is more profitable, because it provides warm-bloodedness and allows a person to occupy exactly the niche in which he is at the moment.

The circulatory system

This system includes a group of musclebodies that have a hollow structure. They are responsible for the process of blood circulation through vessels located in the body. It is represented, in particular, by the heart and blood vessels of different sizes. These muscular organs formed a small and large circle of blood circulation. The scheme given in the article helps to present the mechanism of work visually.

Concept of Circles of Circulation

There is a system of two circles. One of them is called large, or corporeal, and the second - small, or pulmonary. The circulatory system includes arterial, capillary, lymphatic and venous vessels. This system provides the supply of blood to the vessels from the heart, as well as its reverse movement. The heart is the central organ. It is in it that small and large circles of blood circulation cross (the scheme is presented below), and without mixing of venous and arterial blood.

Large or solid circle

A large circle is a system thatprovides peripheral tissue with arterial blood, and then returns it back. It begins with the left ventricle. From it through the aortic opening, which has a tricuspid valve, the blood enters the aorta. Further it goes to other, smaller arteries, reaches the capillaries. These bodies together constitute the leading link.

It is here that oxygen enterstissue, from which then the red blood cells capture carbon dioxide. In addition, blood transports into the tissues glucose, lipoproteins, amino acids and metabolic products, taken out in venules, and then into veins from the capillaries. The veins, in turn, flow into the hollow veins that return the blood to the right atrium of the heart.

Small, large and cardiac circulatory circles have a unique structure.

The body circle ends with the atrium. The circulatory pattern is as follows, if we consider it along the course of the blood flow: it starts from the left ventricle, then comes the aorta, the elastic arteries, then the musculoskeletal and muscle arteries, followed by arterioles, capillaries. They connect with venules, veins and hollow veins, which return blood to the right atrium of the heart. A large circle nourishes the blood of the brain, all skin and bones. Thus, from the large circle all the tissues of the human body feed. A small circle, in turn, is the place of oxygenation of the blood.

Schemes of small and large circles of blood circulation can also be found on the Web.

Pulmonary, or small, circulatory system

The second circle, called pulmonary, starts fromright ventricle. Blood enters it from the right atrium through the atrioventricular orifice. Oxygen-depleted blood, called venous, from the right ventricle cavity enters the pulmonary trunk through the pulmonary (exit) tract. This artery is much thinner than the aorta. It is divided into two branches, directed towards both lungs.

The central organ, which forms a small circle,are the lungs. Pulmonary blood flow is required for oxygenation of the blood. It is here that carbon dioxide is released and oxygen is taken. Gas exchange occurs in sinusoidal pulmonary capillaries, which have a non-typical diameter for the body - about 30 μm. This can be seen in the scheme of small and large circles of blood circulation.

After oxygenation of the blood systemintrapulmonary veins are sent to the pulmonary veins. There are four of them, all of which attach to the left atrium, transferring oxygen enriched with oxygen to it. Circles of blood circulation on this and end. The pulmonary circuit diagram can be described as follows: the right ventricle begins, followed by the pulmonary artery and the pulmonary arteries, followed by the pulmonary arterioles, as well as the pulmonary sinusoids, then the venules and pulmonary veins. He ends with the left atrium.

What else reflects the scheme of small and large circles of circulation?

Characteristic features of the circulatory system

A key feature of the circulatory system,consisting of two circles - the need for a heart that has two or more chambers. For example, in fish, the circulation is the only one, since they do not have lungs, and gas exchange is carried out in the gill vessels. Thus, the heart of fish is one-chambered and plays the role of a pump that pushes blood moving in one direction.

Amphibians and reptiles have lungs, sothey have circulation circles. They work according to a simple scheme: the blood from the ventricle is directed to the vessels forming a large circle, from the arteries directly to the capillaries and veins. In addition, venous return is realized, but from the right atrium blood enters the ventricle, which is common for both circles. Due to the fact that in such animals the heart is three-chambered, then there is a mixture of blood from both circles. A very different picture reflects the scheme of the large and small circle of the person's blood circulation.

Mammals and humans have a four-chambered heart. The presence of partitions in it provides separation into two atriums and two ventricles. It is the absence of mixing of the venous and arterial that provides warm blood to mammals.

Blood supply to the heart and lungs

A special role in the system, consisting of two circles,plays the nutrition of the heart and lungs. They are the most important organs that ensure the integrity of the circulatory and respiratory systems, as well as the closure of the bloodstream. Thus, in the thickness of the lungs there are two circles of blood circulation, nevertheless their tissue is fed by vessels of a large circle: the aorta and the intrathoracic arteries have branches in the form of bronchial and pulmonary vessels that carry blood to the lung and its parenchyma. The pattern of blood flow through the small and large circles of the circulation is very interesting.

Lungs can not be fed from the right divisions,Despite the fact that some of the oxygen diffuses from them. Thus, it can be concluded that the two circles of blood circulation perform various functions: the first enriches the blood with oxygen, and the second transfers it to all organs, and from them takes the blood of dioxygenated.

The heart eats directly from the vesselsa large circle. Blood, which is in its cavities, feeds oxygen to the endocardium. In this case, some veins of the myocardium, mostly small, flow into the heart chambers.

We examined the scheme of small and large circles of blood circulation.