优秀小学生最爱问的600个科学常识（600 Scientific Knowledge That an Excellent Pupil Likes to Ask Mostly）

打嗝儿其实是一种消化道受刺激的症状，极为常见。在人体的胸腔与腹腔之间，有一层横膈，也就是由肌肉组成的膈肌，食道就从中穿过，穿行的地方比较窄。在日常生活中，如果受到什么不良刺激，比方说吃得太快、吃了凉的东西、迎风大口吸入凉气、吃东西太多太饱等，都可能刺激神经，结果通过一系列复杂的神经反射，引起膈肌不正常的强烈收缩，这时，胃里过多的气体就会从嘴巴放出去，振动声带，发出声响，于是我们就打嗝儿了。（Hiccup is a symptom of the digestive tract being stimulated. It is extremely ordinary. There is one layer of septum transversum, being the diaphragm constituted by muscle between the chest and the abdominal cavity of the body, through which the esophagus passes. And the place for passing through is narrow. If there are some pessimal stimulations in daily life, such as eating too fast, eating something cold, breathe into a lot of chilled air facing the wind and eating too full, which all will stimulate the nerve to cause the abnormal intensive contract of the diaphragm through a series of complicated nervous reflex. At that time the excessive gas in the stomach will run out through the mouth. The vocal cord vibrates and makes a noise so we make hiccup.）