Blóðrásirnar

Blóðrásirnar, or the circulatory system, is the network through which blood circulates throughout an organism, carrying oxygen, nutrients, hormones, and waste products to and from tissues. In humans and many vertebrates, the system comprises the heart, blood vessels (arteries, veins, capillaries), and blood. The heart acts as a pump, divided into four chambers: atria, which receive blood, and ventricles, which eject it. The systemic circulation delivers oxygenated blood from the left side of the heart to body tissues, while the pulmonary circulation transports deoxygenated blood to the lungs for gas exchange.

Blood vessels serve as conduits and play roles in regulating blood pressure, filtering waste, and immobilizing pathogens through the immune system. Arteries, especially the aorta, carry high-pressure blood away from the heart; veins return blood to the heart, assisted by muscle contractions and valves that prevent backflow. Capillaries enable exchange of gases and nutrients between blood and cells.

Blood itself consists of plasma, red blood cells, white blood cells, and platelets. Red blood cells, rich in hemoglobin, bind and transport oxygen and carbon dioxide. White blood cells defend against infection; platelets aggregate to form clots that seal damaged vessels.

Dysfunctions of Blóðrásirnar include hypertension, atherosclerosis, aneurysms, and heart failure, which can arise from genetic, lifestyle, or environmental factors. Treatments range from lifestyle changes and medication (e.g., antihypertensives, statins) to surgical interventions such as coronary artery bypass grafting and stent placement. Diagnostic tools include echocardiography, angiography, and blood pressure monitoring.

Research in vascular biology investigates endothelial function, inflammation, and regenerative therapies. Emerging areas such as tissue engineering and gene therapy hold promise for repairing or replacing damaged vascular components. The circulatory system remains a central topic in physiology, medical education, and public health, underscoring the importance of vascular health for overall well-being.