Valgussüsteemi

The circulatory system, also called the cardiovascular system, is a complex network of organs and vessels that transports blood throughout the body, supplying oxygen, nutrients, hormones, and waste removal. It is essential for maintaining homeostasis and supporting metabolic processes, immune function, and thermoregulation.

At the heart of the system are the heart, four chambers (two atria and two ventricles), valves, and cardiac muscle. The heart initiates rhythmic contractions to propel blood through arteries, arterioles, capillaries, venules, and veins. Arteries carry oxygen-rich blood away from the heart, branching into smaller vessels that deliver nutrients to cells. Veins return deoxygenated blood back to the heart, and the lung circulation (pulmonary circuit) exchanges oxygen and carbon dioxide between blood and alveolar air.

Blood functions as a fluid medium that transports cells, proteins, electrolytes, and dissolved gases. It also plays a role in clotting, temperature regulation, and pH balance. The nervous and endocrine systems regulate heart rate and vascular resistance, ensuring blood flow adapts to the body's needs.

Common disorders include hypertension, atherosclerosis, arrhythmias, and heart failure. Lifestyle factors such as diet, exercise, and smoking significantly influence cardiovascular health. Modern medical diagnostics—echocardiography, angiography, and electrocardiography—enable early detection and treatment of circulatory diseases.

The circulatory system remains a primary focus of medical research due to its influence on overall health and longevity. Understanding its function and dysfunction is central to preventive medicine, pharmacology, and regenerative therapies.