How our brain gets a continuous supply of oxygen from the atmosphere?
We breathe in air, take up oxygen, and possess an efficient system of transportation of food (glucose) and oxygen to the brain. Although brain forms only 2% of the body, it uses up to 20% of the oxygen. It is given the top priority during the distribution of oxygen-rich blood. The internal carotid arteries and vertebral arteries carry oxygen-rich blood from the heart to the brain.