The circulatory and respiratory systems of mammals. The organs forming the circulatory system of mammals

In this article we will consider the circulatory system of mammals, its components and features of functioning. For all living organisms, it is of the utmost importance. This is the implementation of gas exchange, transport of nutrients, the formation of immunity and the maintenance of homeostasis. What features are possible for such complex functions?

Who are mammals?

Mammalian animals have a number of systematic features. First of all, this is the feeding of cubs with milk, which is excreted by specialized glands of females. All mammals have limbs that are located under the trunk, and a hairline that periodically changes during molting. In the skin of these animals are contained not only dairy, but also sweat, greasy and odorous glands. Mammals are exclusively warm-blooded organisms, which is ensured by the peculiarities of the circulatory system.

Structure of the circulatory system of mammals

The most progressive features of the structure of the circulatory system among vertebrates are representatives of the class Mammals. It includes a four-chambered heart and a closed vascular system. The blood can fulfill its functions through continuous movement. Therefore, the organs that form the circulatory system in mammals are mainly formed by muscle tissue. And the heart is no exception.

It is a hollow muscular organ consisting of four chambers: two atria and ventricles. These departments are separated by complete partitions and are communicated by means of valves. For this reason, venous and arterial blood never mix, which together with perfect thermoregulatory mechanisms determines the warmth of mammals.

What is warmth-keeping

Warm-blooded animals are those whose body temperature does not depend on the environment. This group includes birds and mammals, including humans. Why do not other animals have this progressive sign? It's all about the structure of the heart. Consider this issue by comparing representatives of different systematic units. Thus, the circulatory system of mammals and reptiles has significant differences. The heart of the latter consists of three chambers, between which is an incomplete partition. It only partially prevents the mixing of venous and arterial blood. Therefore, all reptiles are cold-blooded and are forced to survive the wintering period at the bottom of water bodies, in soil and other shelters.

Two Circles of Circulation

The blood system of mammals also forms vessels. Blood flows through them. Arteries come out of the heart, the largest of which is called the aorta. Further they branch out and pass into capillaries. These are the smallest vessels. The capillary network is collected in venules. Gradually they increase in diameter. So veins form that carry blood in the heart.

The circulatory system of mammals forms two circles of blood circulation. Small passes only through the lungs. It starts in the right ventricle and carries blood along the arteries, capillaries and veins of this organ to the left atrium. As a result, oxygen from the air contained in the lungs passes into the blood, and carbon dioxide - in the opposite direction. A large circle of blood circulation begins in the left ventricle and, passing through the vessels of all organs of the body, carries blood to the right atrium.

Composition of blood

The circulatory system of mammals would not be able to perform its functions without a special liquid tissue that circulates through the vascular system. It's called blood. The basis of this tissue is the intercellular substance - plasma. In it are the uniform elements of three types, each of which performs its functions. Plasma transfers the end products of metabolism from the tissues to the organs of excretion, excess fluid and salts. Since the basis of blood is water, which has a high heat capacity, it maintains a stable body temperature of mammals.

Erythrocytes carry out gas exchange, transporting oxygen and carbon dioxide. These cells also cause red blood color, because they contain iron. Leukocytes form the immunity of organisms. They intracellularly digest foreign particles by phagocytosis. Platelets provide the process of blood clotting. This is a complex chemical process of converting proteins into an insoluble form. Thanks to this body is protected from blood loss. But the realization of all these vital functions is possible only with the combined activity of these cells, heart and blood vessels.

Features of the respiratory system

The circulatory system of mammals is anatomically and functionally associated with the respiratory system. The latter is represented in mammals by airways and lungs. The first consist of a consecutively connected nasal cavity, nasopharynx, larynx, trachea and two bronchi. They are covered with light, which contain a large number of the smallest bubbles - alveoli, braided by a dense network of capillary vessels. It is in the alveoli that gas exchange takes place. The breathing of mammals is a complex process. It involves intercostal muscles, abdominal wall and diaphragm.

The relationship between the circulatory and respiratory systems of mammals

The circulatory and respiratory systems of mammals are closely interrelated. When inhaled, oxygen enters the respiratory tract into the alveoli of the lungs. Hence it penetrates into the capillaries. Entering the blood, oxygen is attached to the red blood cells. These cells instead of nuclei contain a special substance called hemoglobin. It consists of a protein and an iron-containing compound - heme. This chemical element forms a non-stable compound with oxygen. With blood flow, red blood cells carry it all over the body. By giving oxygen, they attach carbon dioxide, which again enters the lungs. With the exhalation this product of metabolism is removed from the body.

So, the circulatory system of mammals forms the heart and blood vessels. It has a closed type. Progressive features of the structure of this system is the presence of four chambers of the heart and a complete partition between them. This determines the warmth of mammals. The respiratory system is connected to the circulatory anatomically and functionally. It consists of airways and lungs. Only due to the coordinated activity of these systems is the respiration of mammals at the cellular, tissue and organism levels.