vena

Vena is the Latin term for a vein, a blood vessel that carries blood toward the heart. In anatomical terminology the word appears most often in fixed Latin names for specific veins, and in the plural venæ. In English usage, many major veins retain the Latin basis in their formal names, such as vena cava (the large veins returning blood to the heart) and vena portae (the portal vein), as well as other examples like vena jugularis and vena femoralis.

Function and structure: Veins form a low-pressure, high-capacitance network that returns blood from the tissues to the heart. With thinner walls and larger lumens than arteries, veins rely on valves in many regions to prevent backflow and to aid blood return, especially in the limbs. The venous system includes superficial and deep veins, as well as venous sinuses such as the coronary sinus that drain the heart muscle itself. Most veins carry deoxygenated blood, while the pulmonary veins carry oxygenated blood from the lungs to the left atrium.

Major components: The systemic venous system culminates in the superior and inferior vena cava, which deliver blood to the right atrium. The hepatic portal system uses the portal vein (vena portae) to transport nutrient-rich blood from the gastrointestinal tract to the liver. Other named veins include the azygos and hemiazygos veins, and numerous named superficial and deep veins throughout the body.

Clinical notes: Vein-related conditions include varicose veins, chronic venous insufficiency, and deep vein thrombosis, which can have serious consequences if untreated. Veins are also a focus of imaging and interventional procedures, including venous Doppler studies and catheter-based therapies.