Head and nerves
Four of the five human sensory organs are found in the head: the nose, eyes, ears and mouth. They lie right next to the body’s sense-processing center, the brain. The brain draws conclusions, makes plans, and triggers quick reactions of the body's muscles by communicating across a chain of nerves. The brain and nerves also regulate a lot of body activities that we are unaware of. Blood pressure, heartbeat and some hormone levels are regulated by the brain.