Sleep and Adenosine

Adenosine leads to sedation. It also dilates your blood vessels, so makes them bigger. If caffeine is ingested, it actually blocks those receptors in the brain. And this prevents adenosine from binding. So you can imagine if you're kind of getting sleepy, you get your venti cappuccino,. What's happening as adenosine is traveling from your bloodstream up into your brain? You feel more alert and less sleepy.