How the brain and the head get oxygen and food?
Although the brain is only about 2% of the total body weight in humans, it receives 15-20% of the body's blood supply. Because brain cells will die if the supply of blood which carries oxygen is stopped, the brain has top priority for the blood. Even if other organs need blood, the body attempts to supply the brain with a constant flow of blood. The blood brings many materials including oxygen, carbohydrates, amino acids, fats, hormones and vitamins necessary for the brain to function properly. The blood also removes materials including carbone dioxide, ammonia, lactate and hormones from the brain. This function is performed by many blood vessels. The head’s blood supply comes mainly from the external and internal carotid arteries. The internal carotid artery travels up from the aortic arch just outside the heart. It travels into the brain to provide oxygenated blood to the eyes, the front of the brain, and portions of the scalp. The external carotid artery helps supply part of the