How does the skin protect us from infection?

How does the skin protect us from infection?

• A. It digests pathogens
• B. It forms a barrier to pathogens trying to enter our body
• C. It produces antibodies
• D. It traps pathogens in the skin

Answer: (B)

The skin protects us mainly by acting as a physical barrier that prevents pathogens from entering the body. The outermost layer, the epidermis, is made of tightly packed keratin-rich cells that form a tough, waterproof shield. This barrier stops most microbes from crossing into deeper tissues. In addition, the skin’s surface is slightly acidic and coated with oils and sweat that contain antimicrobial compounds, which help deter microbial growth on the skin. If invaders do breach the surface, immune sensors in the skin, such as specialized cells, help detect them and trigger immune responses, providing an extra line of defense. The other options don’t fit as the primary protection: the skin doesn’t digest pathogens; antibodies are produced by immune cells elsewhere in the body; and while some pathogens can be trapped superficially, the essential protective function is the barrier.

The skin protects us mainly by acting as a physical barrier that prevents pathogens from entering the body. The outermost layer, the epidermis, is made of tightly packed keratin-rich cells that form a tough, waterproof shield. This barrier stops most microbes from crossing into deeper tissues. In addition, the skin’s surface is slightly acidic and coated with oils and sweat that contain antimicrobial compounds, which help deter microbial growth on the skin.

If invaders do breach the surface, immune sensors in the skin, such as specialized cells, help detect them and trigger immune responses, providing an extra line of defense.

The other options don’t fit as the primary protection: the skin doesn’t digest pathogens; antibodies are produced by immune cells elsewhere in the body; and while some pathogens can be trapped superficially, the essential protective function is the barrier.