Venas

Venas is the plural form of vena in anatomy, referring to vessels that carry blood toward the heart. In humans and most vertebrates, most veins return deoxygenated blood from the tissues, while the pulmonary veins carry oxygenated blood from the lungs to the left atrium. Veins form a low‑pressure, highly compliant network that complements arteries, which transport blood away from the heart under higher pressure.

Vein walls are thinner than arterial walls and consist of three tunics, with a relatively thin tunica media and a comparatively thick adventitia. Many veins contain one‑way valves that prevent backflow, especially in the limbs. In the systemic circulation, veins are organized into superficial and deep networks, and they often run with arteries in paired vessels.

Major venous pathways include the superior and inferior vena cavae, the internal and external jugular veins, and the deep veins of the limbs. The hepatic portal system forms a venous conduit that directs blood from the digestive organs to the liver. Venous blood ultimately returns to the heart through these pathways, aided by skeletal muscle contractions and respiratory movements that promote venous return.

Clinical relevance centers on conditions such as varicose veins and chronic venous insufficiency, deep vein thrombosis (DVT), and pulmonary embolism. Diagnosis commonly uses duplex ultrasonography, venography, or cross‑sectional imaging. Treatments range from compression therapy and lifestyle changes to minimally invasive procedures such as endovenous laser or radiofrequency ablation, sclerotherapy, and surgical vein removal in selected cases.

Vein function is an active area of study in physiology and medicine, with ongoing work to understand venous anomalies, valve function, and the role of venous disease in systemic conditions. The term vena derives from Latin, used historically across medical literature to denote veins.