Q:为什么碰伤的皮肤会有瘀青?(上海市实验学校小学部三(4)班朱媛媛)A:最近老猫我总是昏昏沉沉的,整天处于睡不醒的状态。这不,在办公室竟然滑倒摔了一跤,胳膊撞到桌角青了一大块。唉,真疼啊!瘀青好几天没下去。人体的皮肤下有非常多的毛细血管,这些血管非常细小,而且血管壁非常薄,所以根本经不起外界的压力。如果我们跌跤的时候只是臀部着地,一般是 Q: Why bruising the skin will have bruises? (Shanghai Experimental School Primary Part III (4) classes Zhu Yuanyuan) A: I was always drowsy old cat, sleep in the state all day long. This is not, even in the office slipped and fell, arms hit the desk corner of a large green. Oh, really hurt! Stasis for a few days did not go down. Under the human skin there are many capillaries, these vessels are very small, and the blood vessel wall is very thin, so simply can not stand the pressure of the outside world. If we fall buttocks only when the general is