Head and neck anatomy may be important in the development of the BBB. Astrocytes may also be responsible for transporting ions (electrolytes) from the brain to the blood. Blood from the brain and neck flows from: (1) within the cranium via the internal jugular veins, a continuation of the sigmoid sinuses. The right and left external jugular veins drain from the parotid glands, facial muscles, scalp into the subclavian veins. The right and left vertebral veins drain the vertebrae and muscles into the right subclavian vein and into the superior vena cava, into the right atrium of the heart. The lymphatic system drains the
Hepatic veins Hepatic veins In human anatomy, the hepatic veins are the veins that drain de-oxygenated blood from the liver into the inferior vena cava. There are usually three upper hepatic veins draining from the left, middle, and right parts of the liver. These are larger than the group of lower hepatic veins that can number from six to twenty. All of the hepatic veins drain into the inferior vena cava. They are one of two sets of veins connected to the liver, the others are the portal veins. The large hepatic veins arise from smaller veins found within the liver, and