California Certified Nursing Assistant (CNA) Practice Exam

How does the human body primarily protect itself against infections?

1. Through the shedding of skin cells

2. By maintaining intact skin

3. With active immune response

4. Through respiratory functions

The correct answer is: By maintaining intact skin

The human body primarily protects itself against infections by maintaining intact skin. The skin serves as a physical barrier that prevents pathogens, such as bacteria and viruses, from entering the body. When the skin is intact, it is an effective defense mechanism that helps to keep harmful microorganisms at bay. The outermost layer of the skin, known as the epidermis, is composed of tightly packed cells that create a tough barrier. Additionally, the skin produces antimicrobial substances and oils that further contribute to its protective functions. When this barrier is compromised due to cuts, abrasions, or other injuries, the risk of infection significantly increases, as pathogens can enter more easily. While other options like the immune response and respiratory functions also play vital roles in protecting against infections, they are not the primary means of initial defense. The active immune response becomes more significant after a pathogen has breached the skin barrier, while respiratory functions relate to protecting against airborne pathogens but do not encompass the overall protective role of the skin. Therefore, maintaining intact skin is fundamental to the body's defense against infections.