BR 2-09: Why I sneeze, shiver, Hiccup, and YAWN

I read this book. This book was written about reflex actions. Why do we sneeze? Why do we shiver? Why do we hiccup? Why do we yawn? This book solves out these questions. I thought that reflexes are wonderful for me. I had been thought why these reflexes happen. This book tells detail of it.

Our nervous system is made of two parts. One part is nervous. The other is spinal cord. All reflexes work through your nervous system. When we hiccup, we say "HIC!". To begin with this process, a nerves sends a message to your spinal cord, next an air goes in and your throat closes, so we say "HIC!". In order to stop it, a drink of water may make the hiccups go away. When we sneeze, we say "KA-CHOO!" Why? First, dirt goes in mouth or nose, after that brain gets massage and sends it to spinal cord. Spinal cord gets message and sends it to diaphragm and belly muscles. Then muscles contract. Air is forced out of lungs and into nose and mouth, so we sneeze! Shivering and yawning also reflexes. A yawn begins when lungs have too little oxygen in them. With more oxygen in your lungs, you feels a little less sleep.

We have dozens of different reflexes. I have never thought why these reflexes happen, because these phenomenon are usual things. However our body has wonderful system, I think. I want to know about our body systems more.

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