The circulatory system of human and animal organs
For all multicellularorganisms that have differentiated tissues and organs, the main condition for their life is the need to transfer oxygen and nutrients to the cells that make up their body. The transport function of the above compounds is carried out by blood moving along a system of tubular elastic structures - vessels, united in the circulatory system. Its evolutionary development, structure and functions will be considered in this paper.
Ringworms
The circulatory system of organs first appeared inrepresentatives of the type of annunciators (annelids), one of which is the well-known earthworm - the inhabitant of the soil, which increases its fertility and belongs to the class of small-bristle.
Since this organism is not highly organized, the circulatory system of the bodies of the earthworm is represented by only two vessels - the dorsal and ventral, connected by ring tubes.
Features of the movement of blood in invertebrate animals - mollusks
The circulatory system of organs in mollusks has a numberspecific signs: there is a heart consisting of ventricles and two auricles and distilling blood throughout the body of the animal. It flows not only through the vessels, but also in the intervals between the organs.
Such a circulatory system is called non-closed. A similar structure we see in representatives of the arthropod type: crustaceans, spiders and insects. Their circulatory system of organs is not closed, the heart is located on the dorsal side of the body and has the appearance of a tube with septa and valves.
Lancetnik - ancestral form of vertebrate animals
The circulatory system of the organs of animals havingaxial skeleton in the form of a chord or spine, always closed. The cephalothorax, to which the lancelet belongs, has one circle of circulation, and the abdominal aorta performs the role of the heart. It is her pulsation that ensures blood circulation through the body.
Blood circulation in fish
There are two groups of aquaticorganisms: a class of cartilaginous and a class of bone fish. With significant differences in the external and internal structure, they have a common feature - the circulatory system of organs, the functions of which are to transport nutrients and oxygen. It is characterized by the presence of one circle of blood circulation and a two-chambered heart.
The heart of fish is always two-chambered and consists of the atrium and the ventricle. Between them are valves, so the movement of blood in the heart is always unidirectional: from the atrium to the ventricle.
Blood circulation in the first terrestrial animals
These include representatives of the class of amphibians,or amphibians: a sharp-pointed frog, a tree frog, spotted salamander, newt, and others. The structure of their circulatory system clearly shows the complications of the organization: the so-called biological aromorphosis. This three-chambered heart (two atria and ventricle), as well as two circles of circulation. Both of them start from the ventricle.
In a small circle, blood rich in carbon dioxide,moves to the skin and a bag-shaped lung. Here, gas exchange takes place, and the arterial blood returns from the lungs to the left atrium. Venous blood from the vessels of the skin enters the right atrium, then the arterial and venous blood mix in the ventricle, and such mixed blood moves to all organs of the amphibian body. Therefore, the level of metabolism in them, as in fish, is low enough, which leads to the dependence of the temperature of the amphibian body on the environment. Such organisms are called cold-blooded, or poikilothermic.
The circulatory system in reptiles
Continuing to consider the features of circulationblood in animals that lead the terrestrial way of life, we will dwell on the anatomical structure of reptiles, or reptiles. The circulatory system of organs is more complex in them than in amphibians. Animals belonging to the class of reptiles have a three-chambered heart: two atriums and a ventricle, in which there is a small septum. Animals belonging to the crocodile group have a solid partition in the heart, which makes it four-chambered.
A reptile, included in the squamous group (monitor,gecko, steppe viper, lizard quick) and related to the turtle group, have a three-chambered heart with an unbroken septum, resulting in arterial blood to their forelimbs and head, and mixed to the tail and trunk areas. In crocodiles arterial and venous blood is mixed not in the heart, but outside it - as a result of the fusion of two arcs of the aorta, therefore mixed blood enters all parts of the body. All reptiles without exception are also cold-blooded animals.
Birds are the first warm-blooded organisms
The circulatory system of organs in birds continuesbecome more complex and improve. Their heart is completely four-chambered. Moreover, in two circles of blood circulation arterial blood is never mixed with venous blood. Therefore, the metabolism of birds is extremely intense: body temperature reaches 40-42 ° C, and the heart rate ranges from 140 to 500 beats per minute, depending on the body size of the bird. A small circle of blood circulation, called pulmonary, supplies venous blood from the right ventricle to the lungs, then from them arterial blood, rich in oxygen, enters the left atrium. A large circle of circulation begins from the left ventricle, then the blood enters the dorsal aorta, and already from it along the arteries to all the organs of the bird.
Movement of blood in blood vessels in mammals
Like birds, mammals areThe warm-blooded or homeothermic organisms. In modern fauna, they belong to the first place in terms of the level of adaptation and prevalence in nature, which is primarily due to the independence of their body temperature from the environment. The circulatory system of mammals, whose central organ is a four-chambered heart, is a perfectly organized system of blood vessels: arteries, veins and capillaries. Circulation of blood is carried out on two circles of blood circulation. Blood in the heart is never mixed: the left side is moving the arterial, and the right - the venous.
Thus, the circulatory system of organs in placental mammals ensures and maintains the constancy of the internal environment of the body, that is, homeostasis.
The circulatory system of human organs
Due to the fact that a person belongs to a classmammals, the general plan of the anatomical structure and functions of this physiological system in him and the animals is quite similar. Although the uprightness and related specific features of the structure of the human body still left a certain imprint on the mechanisms of blood circulation.
The circulatory system of human organs consists offour-chambered heart and two circles of blood circulation: small and large, which were discovered in the 17th century by the English scientist William Harvey. Of particular importance is the blood supply of such human organs as the brain, kidneys and liver.
Vertical position of the body and blood supply to the pelvic organs
Man is the only creature in the classmammals, whose internal organs press their weight not on the abdominal wall, but on the waist of the lower extremities, consisting of flat pelvic bones. The circulatory system of the pelvic organs is represented by a system of arteries that fit from the common iliac artery. This is primarily the internal iliac artery, which brings oxygen and nutrients to the organs of the small pelvis: the rectum, the bladder, the genital organs, the prostate gland in men. After the gas exchange takes place in the cells of these organs and the arterial blood becomes venous, the vessels - iliac veins - flow into the lower hollow vein, which carries blood into the right atrium, where a large circle of blood flows.
It must also be taken into account that all the organs of the smallThe pelvis is a fairly large formation, and they are located in a relatively small volume of the body cavity, which often causes the blood vessels that feed these organs to be transmitted. Usually it arises from prolonged sedentary work, in which the blood supply to the rectum, bladder and other parts of the body is disturbed. This leads to stagnant phenomena that provoke infection and inflammation in them.
Blood supply of human genital organs
Ensuring the normal course of reactionsplastic and energy metabolism at all levels of the organization of our body, beginning with the molecular and ending with the organism, performs the circulatory system of human organs. The organs of the small pelvis, which includes the genitals, are blood supply, as already mentioned above, from the descending part of the aorta, from which the abdominal branch departs. The circulatory system of the genital organs is formed by a system of vessels providing nutrients, oxygen and removing carbon dioxide, as well as other metabolic products.
Male gonads - testicles in whichthe spermatozoa mature, - arterial blood is obtained from the testicles leaving the abdominal aorta, and the outflow of venous blood is carried out by the testic veins, one of which - the left one - merges with the left renal vein, and the right enters directly into the lower vena cava. The penis is supplied with blood vessels that extend from the internal sexual artery: it is the urethral, dorsal, bulbous and deep arteries. The movement of venous blood from the tissues of the penis provides the largest vessel - a deep dorsal vein from which the blood moves to the genitourinary venous plexus associated with the inferior vena cava.
Blood supply of female genital organsis performed by the system of arteries. Thus, the perineum receives blood from the internal sexual artery, the uterus is supplied with the branch of the abdominal artery, called the uterus, and the ovaries are provided with blood from the abdominal aorta. In contrast to the male reproductive system in the female, the venous network of blood vessels connected by bridges - anastomoses - is very developed. Venous blood flows into the ovarian veins that enter the inferior vena cava, which then flows into the right atrium.
In this article, we examined in detail the development of the circulatory system of the organs of animals and man, providing the body with oxygen and nutrients necessary for life support.
