在人体中，有许多道“屏障”，构成严密的防御体系。这些屏障不仅能防范“外敌入侵”，同时在体内有着重要的生理功能。 皮肤与粘膜屏障 堪称人体的天然屏障，构成人体的第一道防线。皮肤是人体中最大的器官，它与粘膜能将人体完整地保护起来。不仅可以抵御外来病菌、异物的入 In the human body, there are many “barriers” that form a tight defense system. These barriers not only prevent “foreign invasion”, but also have important physiological functions in the body. Skin and mucous membrane barrier called the body’s natural barrier, constitute the body’s first line of defense. The skin is the largest organ in the human body, it can completely protect the human body with the mucous membrane. Not only can resist foreign bacteria, foreign body into