The skin functions as an important barrier to which of the following?

• A. Bone fractures
• B. Muscle contraction
• C. Oxygen absorption
• D. Pathogens and harmful substances

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the primary function of the skin in the human body. The skin is the largest organ and serves as a protective barrier against external environmental factors.
2. Step 2: Recognize that the skin is part of the integumentary system, which includes structures like hair, nails, and glands. Its primary role is to protect the body from physical damage, dehydration, UV radiation, and invasion by pathogens.
3. Step 3: Analyze the options provided in the question. Bone fractures and muscle contraction are internal processes that are not directly influenced by the skin's barrier function. Oxygen absorption primarily occurs in the lungs, not through the skin.
4. Step 4: Focus on the correct answer: Pathogens and harmful substances. The skin acts as a physical and chemical barrier, preventing microorganisms and toxic substances from entering the body. It achieves this through its tightly packed cells, acidic pH, and antimicrobial secretions.
5. Step 5: Conclude by emphasizing the importance of the skin's barrier function in maintaining homeostasis and protecting the body from infections and harmful external agents.