Circulatory System
Rajapova Muqaddas Umidbek qizi
Samarkand State Medical University
Faculty of Pediatrics, Group 112
Nurzodbekova Yasmina Nurzodbekovna
Samarkand State Medical University
Faculty of Pediatrics, Group 114
Rahimova Madina Mannonovna
Samarkand State Medical University
Department of Physiology, Trainee Assistant
madinarakhimova79@gmail.com
Abstract:
This article discusses one of the most important systems in the human body — the circulatory system. It is well known that this system affects all other systems, meaning that when the circulatory system is impaired, cells do not receive sufficient nutrients, and organ functions weaken.
Keywords: Epicardium, myocardium, endocardium, carbon dioxide, automatism, rib, clinical, atherosclerosis, hypertension, aneurysm, phlebothrombosis, varicose veins, thrombophlebitis.
Introduction:
The main function of the circulatory system in the human body is to deliver oxygen and nutrients to cells and to remove carbon dioxide and other waste products. This process is carried out through the coordinated functioning of the heart and blood vessels. The heart acts as a central pumping organ, while blood vessels distribute blood throughout the body and return it to the heart. This complex system remains in constant motion and functions steadily throughout
life.
Anatomical Structure of the Heart
The heart is a four-chambered, muscular, cone-shaped organ located in the central part of the chest cavity between the right and left lungs. It consists of the epicardium, myocardium, and endocardium.
Epicardium – the outer layer of the heart, covered by the pericardium.
Myocardium – the main and thickest layer of the heart wall, responsible for contraction.
Endocardium – a thin layer lining the inner surface of the heart chambers.
The heart has four chambers: right and left atria, and right and left ventricles.
Between the chambers are valves: mitral, tricuspid, aortic, and pulmonary valves.
Cardiac automatism is the ability of specialized cardiac cells to independently generate bioelectrical impulses that stimulate heart contractions.
Main Part
The heart is located in the thoracic cavity, slightly shifted to the left. Two-thirds of the heart lies to the left of the midline, and one-third to the right. Laterally and partially anteriorly, the heart is adjacent to the lungs, while its front part touches the sternum and rib cartilages.
Relative to the body’s midline, the heart is asymmetrically positioned: about two-thirds on the left and one-third on the right. Depending on the projection of the vertical axis, the heart may have transverse, oblique, or vertical positions.
A vertical position is more common in people with narrow and long chests, while a transverse position is more common in those with wide and short chests. In newborns, the heart is more vertical, rounded in shape, and located higher because the atria are larger and the ventricles are less developed. As a person approaches adulthood, the heart assumes its typical position.
The heart consists of four separate chambers:
Left atrium (atrium sinistrum)
Right atrium (atrium dextrum)
Left ventricle (ventriculus sinister)
Right ventricle (ventriculus dexter)
Diseases of the Circulatory System
Diseases of the vascular system are widespread and are associated with structural and functional disorders of blood vessels.
Arterial Diseases
Atherosclerosis: Accumulation of cholesterol plaques in vessel walls, narrowing blood flow. It is a major cause of heart attacks and strokes.
Arterial hypertension: Chronic elevation of blood pressure.
Aneurysm: Weakening and ballooning of the arterial wall, with a high risk of rupture.
Obliterating endarteritis: Inflammation and narrowing of leg arteries, often found in smokers.
Venous Diseases
Varicose veins: Dilation of veins due to valve dysfunction and blood stagnation.
Thrombophlebitis: Inflammation of vein walls with clot formation.
Phlebothrombosis (Deep vein thrombosis): Formation of clots in deep veins, which may cause pulmonary embolism.
Microcirculation and Other Disorders
Vasculitis: Inflammation of vessel walls due to immune reactions.
Raynaud’s syndrome: Sudden constriction of small blood vessels in fingers due to cold or stress.
Lymphedema: Impaired lymph drainage leading to swelling.
Main Causes of Cardiovascular Diseases
Physical inactivity (hypodynamia)
Unhealthy diet (fatty and salty foods)
Harmful habits (smoking and alcohol)
Genetic predisposition
Obesity and diabetes
Environmental Factors and Cardiovascular Health
The cardiovascular system is highly sensitive to environmental factors. Research shows that air pollution, sudden temperature changes, noise, stress, and harmful habits are major contributors to heart disease.
Fine particles such as PM2.5 and PM10 can cause narrowing of blood vessels and heart rhythm disorders. Cold weather increases blood pressure, while excessive heat disrupts fluid balance and increases the risk of thrombosis. Noise and stress raise cortisol levels, leading to cardiac strain and heart failure.
The socio-economic consequences of cardiovascular diseases affect patients, families, healthcare systems, and overall quality of life. About 60% of cardiovascular complications are associated with major risk factors such as smoking, alcohol abuse, insufficient intake of fruits and vegetables, and sedentary lifestyles. These factors contribute to obesity, hypertension, high blood sugar, and
high cholesterol levels. Studies conducted in Uzbekistan show that the prevalence of risk factors for non- communicable diseases is steadily increasing.
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