Hereditary diseases of the cardiovascular system
The heart is the central organ of the cardiovascular system of any living organism.It is a muscular organ, which consists of two atria and two ventricles (right and left).The atria and ventricles are arranged above each other separated by the interatrial septum, consisting of muscle tissue.Heart ventricles and atria are arranged at separated by the interventricular septum, consisting of muscle tissue.This partition has two parts: the upper part - membranous (membranous), the lower part (large) - muscle.The atria are separated from the ventricles by means of valves.Between the right atrium and ventricle is the tricuspid (tricuspid) valve, and between the left - bicuspid (mitral).The wall of the heart consists of three layers: an inner - endocardium, the middle - the myocardium (the muscle tissue is formed) and the outer - the epicardium.The heart is located in the chest cavity and is enclosed in connective tissue bag - the pericardial sac (pericardium), which has a protective function.In humans there are
process is called ventricular systole.From the aorta, which is the largest vessel of the body, blood is carried through the arteries to all organs and tissues.Then, from the bodies of the blood collected in the veins.All veins are combined in the two largest: the upper and lower vena cava.The upper hollow Vienna collects blood from the head, neck and upper torso.Lower hollow Vienna collects blood from the lower body.Both vena cava end up in the right atrium, bringing here, "spent" by the blood of the whole body.The blood from the right atrium enters the right ventricle, from where originates the pulmonary circulation.From the right ventricle goes pulmonary trunk, which is divided into right and left pulmonary arteries.On the right pulmonary artery blood is delivered to the right lung, the left - to the left.In the lungs the blood is enriched with oxygen, and then the four pulmonary veins to the left atrium is sent, where it ends the pulmonary circulation.From there the blood rich in oxygen flows into the left ventricle.Heart Work consists of three phases: reduction of atrial - atrial systole, ventricular - ventricular systole, the total pause - diastole.In atrial systole blood flows into the ventricles at systole ventricles - expelled into the vessels.Then there is a pause in the work of the heart, during which the heart muscle is "resting."In systole and diastole phase duration equal, ie. E. Half of all life the heart is at rest.
The baby developing in the mother's body, the blood circulation takes place in a slightly different way.In the fetus, there is only one circulation - large, but it has its own peculiarities.Blood is supplied to the fetus from the placenta by the umbilical vein, which runs as part of the umbilical cord.In the body of the child's umbilical Vienna is divided into two vessels.One of them is directed to the liver, and the other flows into the inferior vena cava.Since by the placenta and umbilical vein of the fetus receives blood rich in oxygen and nutrients, and in the inferior vena cava flows "Waste" blood is then mixed blood that enters the right atrium in the last vessel.From there, a very small portion of the blood is sent to the "usual" way, as it does in adults, t. E. It flows into the right ventricle.However, most of the blood from the right auricle enters the left atrium.It would seem, how this could occur if the atria are separated by atrial septal?However, the fetus in the partition wall has a hole through which is carried out and so unusual movement of blood.This hole in the atrial septum called the oval.
the fetus, as well as in adults, the upper hollow Vienna collects blood from the head, neck and upper torso.For this vein blood enters the right atrium, and then into the right ventricle.Thereafter, the blood should normally occur and enters the pulmonary trunk, t. E. In the pulmonary circulation.But the child in utero lung vessels are undeveloped.In this connection, the blood flows from the pulmonary artery to the aorta.Again the question arises: how does this happen?It turns out that between the pulmonary trunk and the aorta also have a message - arterial (Botallo) duct.
After giving birth, when there is a cutting of the umbilical cord, the blood flow stops, oxygen-enriched by the umbilical vein.This leads to oxygen deficiency in the body of the newborn baby, which causes the activation of specific structures in the brain that are responsible for the first breath.After the first breath occurs unfolding lungs and blood vessels, which is accompanied by the beginning of the functioning of the pulmonary circulation.At the same time there is a reflex contraction of blood (botallova) duct, which is completely overgrown with 1,5-2 months after birth.The oval hole in this time, the gap narrows to the size and completely overgrown by 5-6 months of life.
Due to the effect of different reasons, first of all, of course, genetic, there are various abnormalities in heart development and the closing of existing communications in utero to such an unusual movement of the blood, which can lead to congenital heart defects.
The incidence of abnormalities of the cardiovascular system is 1% of all live births.In modern medicine, not difficult early diagnosis of abnormalities of the cardiovascular system, causing possible to save most of the children using the medical or surgical treatment.In most cases, congenital heart defects occur in newborn males.
Congenital cardiovascular system is usually the result of abnormal heart development during pregnancy.Malformations are the result of exposure to a whole range of others, and genetic factors.Only 1% of cases it is possible to identify any one direct cause that led to the emergence of diseases.Mutation of genes can cause inherited forms of reverse arrangement of the internal organs (mirroring), prolapse of the left atrioventricular (mitral) valve defect atrial and ventricular septal and others. However, gene mutations are the cause of less than 10% of all congenital heart defects.Birth of a child with congenital heart disease involves a low risk of having a second child with such deviation.This fact, as well as the continuous development of methods of treatment of congenital heart defects and continually increasing their efficiency, allow us to recommend the parents to consider favorably the birth of her second child.The risk of birth of the patient improved significantly, if two or more members of the family has a heart defect.The risk of a baby with a defect in repeated pregnancies can be predicted fairly accurately, if it is possible to establish that the inheritance of vice has a dominant or recessive character in accordance with the law of Mendel.
Currently, due to the presence of an effective vaccine available against rubella, the risk of congenital heart defects has decreased significantly.In connection with the possibility of pathological effects on the fetus, none of the of drugs should not be taken during pregnancy without first consulting your doctor.