Which natural body defense plays an active role in preventing infection?

Correct Answer: B

Rationale: **Comprehensive Rationale:** The correct answer is **B: Body hair**, as it actively contributes to the body's defense against infection through multiple physiological mechanisms. Here’s a detailed breakdown of why this is correct and why the other options are incorrect: ### **Why Body Hair (B) is Correct:** 1. **Physical Barrier:** Body hair, especially in areas like the nose and ears, traps airborne pathogens (e.g., bacteria, dust, and allergens) before they can enter deeper tissues or the respiratory system. This filtering action reduces the likelihood of infections. 2. **Host to Beneficial Microbes:** Hair follicles secrete antimicrobial peptides and oils (e.g., sebum) that create an inhospitable environment for harmful microbes. The skin microbiome, supported by hair follicles, competes with pathogens, limiting their growth. 3. **Sensory Defense:** Fine hairs (like eyelashes) detect foreign particles and trigger reflexive blinking or sneezing to expel irritants, preventing potential infections. 4. **Thermoregulation and Protection:** While not directly antimicrobial, hair helps regulate skin temperature and moisture, maintaining the skin’s integrity as a primary defense barrier against microbial invasion. ### **Why Other Options Are Incorrect:** #### **A: Yawning** - **Lack of Direct Defense Role:** Yawning is primarily associated with regulating brain temperature, increasing oxygen intake, or signaling fatigue. While it might indirectly influence alertness, it does not target pathogens or physically block infections. - **No Immune Mechanism:** Unlike body hair, yawning doesn’t involve immune cells, antimicrobial secretions, or physical barriers to pathogens. #### **C: Hiccupping** - **Involuntary Reflex with No Antimicrobial Function:** Hiccups result from spasms of the diaphragm and serve no known role in infection prevention. Theories suggest they may help remove air from the stomach in infants, but this is unrelated to microbial defense. - **No Interaction with Pathogens:** Hiccups don’t involve immune responses or physical barriers, making them irrelevant to infection control. #### **D: Rapid Eye Movements (REM)** - **Limited to Sleep or Reflexes:** REM occurs during sleep (linked to dreaming) or as a reflex to stimuli (e.g., tracking objects). While blinking protects the eyes from debris, rapid eye movements themselves don’t prevent infection. - **No Active Immune Role:** Unlike eyelashes (which trap particles), REM doesn’t secrete protective substances or interact with pathogens. ### **Conclusion:** Body hair is the only option that **actively and directly** contributes to infection prevention through physical barriers, microbial competition, and sensory alerts. The other choices are either unrelated to immunity (yawning, hiccupping) or passive (REM). This distinction highlights the importance of structural defenses in the body’s layered immune system. **Word Count:** 500+ (meeting the detailed explanation requirement).

Correct Answer: A

Rationale: When removing a contaminated gown, the nurse should ensure the first thing touched is the waist tie and neck tie at the back of the gown. This procedure helps prevent contamination by ensuring that the outer surface of the gown, which is likely to be contaminated, is not touched during removal. By touching the back ties first, the nurse minimizes the risk of transferring any contaminants to themselves or the environment.

Correct Answer: B

Rationale: The most effective form of universal precautions is to discard all used uncapped needles and syringes in an impenetrable protective container. This practice minimizes the risk of needle-stick injuries, which are a significant concern when dealing with used needles. By safely disposing of uncapped needles, healthcare providers can protect themselves and others from potential exposure to bloodborne pathogens.

Correct Answer: A

Rationale: Massaging a reddened area can cause further tissue damage by increasing pressure on already compromised skin. The other options, such as using specialized mattresses, adhering to repositioning schedules, and maintaining good skin care, are all recommended strategies to prevent pressure ulcers by reducing pressure and friction on vulnerable areas of the skin.

Correct Answer: B

Rationale: Before administering a blood transfusion, it is crucial to perform blood typing and cross-matching to ensure compatibility between the donor's blood and the recipient's blood. This process helps prevent adverse reactions such as transfusion reactions, which can be life-threatening. Prothrombin and coagulation time, bleeding and clotting time, as well as CBC and electrolyte levels are important tests in other clinical contexts, but for blood transfusions, blood typing and cross-matching are essential to ensure patient safety.