In our article we will consider the circulatory system of mammals, its components and features of functioning. It is essential for all living organisms. This is the implementation of gas exchange, the transport of nutrients, the formation of immunity and the maintenance of homeostasis. What features make such complex functions possible?
Who are mammals
Mammals have a number of systematic features. First of all, this is the feeding of young with milk, which is secreted by the specialized glands of females. All mammals have limbs that are located under the body, and hairline, which periodically changes during molting. The skin of these animals contains not only milk, but also sweat, sebaceous and odorous glands. Mammals are exclusively warm-blooded organisms, which is ensured by the peculiarities of the circulatory system.
The structure of the circulatory system of mammals
The most progressive features of the structure of the circulatory organs among vertebrates are representatives of the class Mammals. It includes a four-chambered heart and a closed vascular system. Blood is able to perform its functions due to continuous movement. Therefore, the organs that form the circulatory system in mammals are mainly formed by muscle tissue. And the heart is no exception.
This is a hollow muscular organ consisting of four chambers: two atria and ventricles. These departments are separated by complete partitions and communicate with valves. For this reason, venous and arterial blood never mix, which, together with the perfect mechanisms of thermoregulation, determines the warm-bloodedness of mammals.
What is warm-bloodedness
Warm-blooded animals are called animals whose body temperature does not depend on the environment. Birds and mammals, including humans, belong to this group. Why do other animals not have this progressive trait? It's all about the structure of the heart. Let's consider this question 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 there is an incomplete septum. It only partially prevents mixing of venous and arterial blood. Therefore, all reptiles are cold-blooded and are forced to survive the wintering period at the bottom of reservoirs, in soil and othershelters.
Two circles of blood circulation
The circulatory system of mammals is also formed by vessels. They carry blood through them. Arteries emerge from the heart, the largest of which is called the aorta. Then they branch out and pass into the capillaries. These are the smallest vessels. The capillary network is collected in venules. Gradually they increase in diameter. This is how the veins that carry blood to the heart are formed.
The circulatory system of mammals forms two circles of blood circulation. Small passes only through the lungs. It begins in the right ventricle and carries blood through 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. The systemic 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 carry out 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. It contains shaped elements of three types, each of which performs its own functions. Plasma carries end products of metabolism, excess fluid and s alts from tissues to excretory organs. Since blood is based on water, which has a high heat capacity, it maintains a stable temperature.bodies of mammals.
Erythrocytes carry out gas exchange, transporting oxygen and carbon dioxide. These cells are also responsible for the red color of the blood because they contain iron. Leukocytes form the immunity of organisms. They digest foreign particles intracellularly by phagocytosis. Platelets provide the process of blood clotting. It is a complex chemical process of turning proteins into an insoluble form. Thanks to this, the body is protected from blood loss. But the implementation of all these vital functions is possible only with the combined activity of these cells, the 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 the nasal cavity, nasopharynx, larynx, trachea and two bronchi connected in series. They are covered with lungs, which contain a large number of tiny vesicles - alveoli, braided with a dense network of capillary vessels. It is in the alveoli that gas exchange takes place. The respiration of mammals is a complex process. It involves the intercostal muscles, the walls of the abdominal cavity and the diaphragm.
The relationship between the circulatory and respiratory systems of mammals
The circulatory and respiratory systems of mammals are closely interconnected. When you inhale, oxygen enters the airways into the alveoli of the lungs. From there, it enters the capillaries. Entering the blood, red blood cells attach oxygen. 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 an unstable compound with oxygen. With the blood stream, red blood cells carry it throughout the body. Giving up oxygen, they add carbon dioxide, which again enters the lungs. With exhalation, this metabolic product is removed from the body.
So, the circulatory system of mammals is formed by the heart and blood vessels. It has a closed type. The progressive features of the structure of this system are the presence of four chambers of the heart and a complete partition between them. This determines the warm-bloodedness of mammals. The respiratory system is anatomically and functionally connected with the circulatory system. It consists of airways and lungs. It is only thanks to the coordinated activity of these systems that mammals breathe at the cellular, tissue and organism levels.
