Cardiovascular system. Circulation.

Circulation circles

Blood locomotion in an organism descends on two closed systems of the pots bridged to heart, - to the big and small circle of a circulation. More in detail about everyone:

The big circle circulations (corporal). Begins an aorta which departs from a left ventricle. The aorta gives rise to large, average and fine arteries. Arteries pass in arterioles which come to an end with capillars. Capillars a wide network penetrate all organs and organism tissues. In capillars blood gives oxygen and nutrients, and from them receives metabolism products, including a carbon dioxide. Capillars pass in the venules which blood collects in fine, average and large veins. Blood from the top part of a trunk arrives in the top vena cava, from inferior - in the inferior vena cava. Both these veins run into the right auricle in which the big circle of a circulation comes to an end.

Small circle circulations (pulmonary). Begins a pulmonary fulcrum which departs from a right ventricle and carries in lungs a venous blood. The pulmonary fulcrum branches on two branches going to the left and right lung. In lungs pulmonary arteries share on fineer arteries, arterioles and capillars. In capillars blood gives a carbon dioxide and is enriched by oxygen. Pulmonary capillars pass in venules which then form veins. On four pulmonary veins the arterial blood arrives in the left auricle.

The blood circulating on the big circle of a circulation, provides all cells of an organism with oxygen and nutrients and carries away from them metabolic products.

The role of a small circle of a circulation consists that in lungs restoration (neogenesis) of gas structure of blood is carried out.

Age features of a circulation system

Hygiene warmly - vascular system.

The human body has the ontogeny from the moment of a fertilization before the natural terminal of life. This season name an ontogenesis. In it excrete two independent stages: prenatal (from the moment of conception till the birth moment) and postnatal (from the moment of a birth to mors of the human). In each of these stages there are features in a constitution and functioning of system of a circulation:

Age features in a prenatal stage. Formation of heart of an embryos begins with 2 weeks of prenatal development, and its development in general comes to an end to the extremity of 3 weeks. The foetus circulation has the features bound, first of all that till a birth oxygen arrives in an organism a foetus through a placenta and a so-called umbilical vein. The umbilical vein branches on two pots, one feeds a liver, another is bridged to the inferior vena cava. As a result in the inferior vena cava there is a mixture of the blood rich with oxygen, to the blood passed through a liver and containing products of an exchange. Through the inferior vena cava blood gets to the right auricle. Further blood passes in a right ventricle and then is pushed out in a pulmonary artery; the smaller part of blood streams in lungs, and the most part through arterial duct gets to an aorta. Presence arterial duct, bridging an artery with an aorta, is the second specific feature in a foetus circulation. As a result of bond of a pulmonary artery and an aorta both heart ventricle force blood in the big circle of a circulation. Blood with exchange products comes back in a maternal organism through umbilical arteries and a placenta.

Thus, circulation in an organism of a foetus of the admixed blood, its communication through a placenta with system of a circulation of mother and presence arterial duct is the basic features of a circulation of a foetus.

Age features in a postnatal stage. At the neonatal child communication with a maternal organism stops also its own system of a circulation incurs all necessary functions. Arterial duct loses the functional value and soon grows with a copulative tissue. At children the relative mass of heart and the general lumen of pots more than at adults, that substantially facilitates circulation processes.

Whether there are patterns in heart growth? It is possible to notice, that heart growth is in a close connection with the general growth of a body. The most intensive growth of heart is observed in the first years of development and in the end of the teenage season.

Also the form and position of heart in a thorax variates. At newborns heart of the ball-shaped form also is located considerably above, than at the adult. These differences are liquidated only to 10-year-old age.

Functional differences in cardiovascular system of children and teenagers remain till 12 years. Frequency of a warm rhythm at children more than at adults. The CARDIAC CONTRACTIONS RATE at children it is more subject to influence of choronomic influences: physical exercises, an emotional pressure etc. the Blood pressure at children more low, than at adults. The stroke output at children is much less, than at adults. With the years the minute volume of blood that provides to heart adaptic possibilities to exercise stresses is enlarged.

In the seasons of puberty descending in an organism rough processes of growth and development influence, on an internals and, especially, on warm - vascular system. At this age disharmony of the dimension of heart to diameter of veins becomes perceptible. At a tachyauxesis of heart veins grow more slowly, their lumen is insufficiently wide, and in this connection heart of the teenager carries an additional load, pushing blood on narrow pots. For the same reason the teenager can have time disturbance of a food of a cardiac muscle, undue fatigability, the easy dyspnea, unpleasant sensations in the field of heart.

Other feature warmly - vascular system of the teenager is that heart at the teenager very quickly grows, and development of the excitatory apparatus regulating a cardiac performance, is not in time behind it. As a result at teenagers palpitation, an irregular heart rhythm, etc. All listed changes temporary are sometimes observed and arise in connection with feature of growth and development, instead of as a result of illness.

Hygiene warmly - vascular system. For normal development of heart and its activity extremely essential to exclude the excessive physical and mental strains breaking normal rate of a cardiac performance, and also to provide its training by physical exercises rational and accessible to children.

Gradual training of warm activity provides perfection of contractile and elastic properties of muscular fibers of heart.

Training warmly - vascular activity is reached by daily spent physical exercises, sports employment and moderate physical work, especially when they are spent on fresh air.

Hygiene of organs of a circulation at children makes certain demands to their clothes. Close clothes and narrow dresses squeeze a thorax. Narrow collars squeeze neck veins that is reflected in a circulation in a brain. Hard girdles squeeze veins of a lumen of a gaste and by that complicate a circulation in circulation organs. The close footwear is unfavorablely reflected in a circulation in the inferior extremities.