Vasculature of the Head
Blood is carried from your heart to the rest of your body through a complex network of arteries, arterioles, and capillaries. Blood is returned to your heart through venules and veins.
The one-way vascular system carries blood to all parts of your body. This process of blood flow within your body is called circulation. Arteries carry oxygen-rich blood away from your heart, and veins carry oxygen-poor blood back to your heart.
In pulmonary circulation, though, the roles are switched. It is the pulmonary artery that brings oxygen-poor blood into your lungs and the pulmonary vein that brings oxygen-rich blood back to your heart.
Like the heart, the brain’s cells need a constant supply of oxygen-rich blood. This blood supply is delivered to the brain by the two large carotid arteries in the front of your neck and by two smaller vertebral arteries at the back of your neck.
The right and left vertebral arteries come together at the base of your brain to form what is called the basilar artery in the vasculature of your head.
As shown in the diagrams of the vasculature of the head, the vessels that carry oxygen-rich blood are colored red, and the vessels that carry oxygen-poor blood are colored blue.