人类与病原体斗争,有一套从遗传而来的天然防御组织和机能,包括能抵抗和消灭入侵的病原体的两道防线。第一道防线主要指皮肤和黏膜。皮肤是人体的完整外表,表面有一层较厚的致密角化层,可以阻挡病原体侵入。皮肤组织里还有许多汗腺和皮脂腺,汗腺排泄出的乳酸对病原体的生长不利,皮脂腺分泌的脂肪酸有一定的杀菌作用。皮肤的杀菌作用是很强的, Humans struggle with pathogens and have a natural defense organization and function that has been inherited, including the two lines of defense against and elimination of invading pathogens. The first line of defense mainly refers to the skin and mucous membranes. The skin is the body’s full appearance, the surface has a thick layer of dense keratosis, can stop the pathogen intrusion. There are many skin and sweat glands and sebaceous glands, lactic acid excreted by sweat glands adversely affected the growth of pathogens, sebaceous glands secrete fatty acids have a bactericidal effect. The bactericidal effect of the skin is very strong,