The brain receives its blood supply primarily through two pairs of arteries: the internal carotid arteries and the vertebral arteries. The internal carotid arteries branch from the common carotid arteries and supply the anterior part of the brain, while the vertebral arteries, which arise from the subclavian arteries, supply the posterior part. These arteries form a network known as the Circle of Willis, ensuring a continuous blood flow. Oxygen and nutrients carried by the blood are essential for brain function. The brain consumes about 20% of the body's oxygen, despite accounting for only about 2% of its weight. Any disruption in this blood supply can lead to serious conditions, such as a stroke.