新八下Unit2 拓展阅读补充视频 打喷嚏背后的科学原理 人为什么会打喷嚏。打喷嚏是身体清除鼻腔内刺激物（如灰尘、宠物毛发）的一种自然反射过程。当刺激物进入鼻腔，大脑会协调眼、舌、胸腹等多处肌肉，以极快速度将异物连同空气和黏液喷出。除了物理刺激，感冒、病毒或过敏（如花粉、皮屑）也是常见诱因。视频还提醒，打喷嚏会传播病菌，因此应用纸巾或手肘遮挡。视频结尾处介绍了一个有趣的冷知识：有些人一见到强光就会打喷嚏，这被称为"光喷嚏反射"，是一种遗传特征。the science behind sneezingA sneeze is your body's natural reflex to expel irritants (like dust or pet hair) from your nasal passages. When an irritant enters the nose, the brain coordinates muscles in the eyes, tongue, chest, and abdomen to forcefully blast the particles out with air and mucus at high speed. Besides physical irritants, common triggers include colds, viruses, and allergies (e.g., to pollen or dander). The video also emphasizes covering your mouth with a tissue or elbow, as sneezes spread germs. As a fun fact, it introduces the "photic sneeze reflex," where bright light triggers sneezing—a genetic trait inherited from parents.#初中英语备课 #新八下英语 #新八下英语课件 #人教版八年级英语 #新八下unit2
15
抢首评
5
11
举报
发布时间：2026-03-08 09:00全部评论
大家都在搜：
