Why are the skin and mucous membranes considered components of non-specific (innate) immunity?

• A. They provide general physical and chemical barriers that prevent entry of a wide range of pathogens.
• B. They produce antibodies that specifically target invading microbes.
• C. They recognize and remember specific pathogens for faster response upon re-exposure.
• D. They are only effective against viral infections and not bacterial infections.

Answer: (A)

Verified step by step guidance

1. Understand the concept of non-specific (innate) immunity: it refers to the body's first line of defense that acts immediately or within hours of an antigen's appearance in the body, providing a general defense against a wide range of pathogens without targeting specific ones.
2. Recognize that skin and mucous membranes serve as physical barriers by blocking the entry of pathogens into the body, preventing their access to underlying tissues.
3. Identify that these barriers also have chemical defenses, such as acidic pH, enzymes, and antimicrobial secretions, which inhibit or destroy many microbes nonspecifically.
4. Contrast this with specific (adaptive) immunity, which involves the production of antibodies and memory cells that target particular pathogens, a function not performed by skin and mucous membranes.
5. Conclude that because skin and mucous membranes provide broad, non-specific protection through physical and chemical means, they are considered components of the innate immune system.