As it binds to adenosine receptors, it slows down our nerve cell activity, which then causes drowsiness. A nerve cell mistakes caffeine for adenosine. Therefore, caffeine binds with the adenosine receptor, but rather than slowing down the cell's activity, the nerve cells speed up. While adenosine opens up blood vessels, allowing for more oxygen intake, caffeine constricts these blood vessels.
windshield - transparent screen (as of glass) to protect occupants of a vehicle. windscreen. aeroplane, airplane, plane - an aircraft that has a fixed wing and is powered by propellers or jets; the flight was delayed due to trouble with the airplane.
Automobiles use a different type of safety glass for the windshield and tempered glass for the back and side windows. Windshields are made from laminated glass, which sandwiches a sheet of plastic between two panels of glass.