Which of the following is NOT a function of the skin?
Select one:
a. Production of Vitamin D
b. Protection against microbes
c. Water absorption
d. Temperature regulation
e. Collection of sensory information
The correct answer and explanation is :
The correct answer is: c. Water absorption
Explanation:
The skin, also known as the integumentary system, is the body’s largest organ and serves multiple critical functions that are essential for maintaining health and homeostasis. Let’s break down the options to understand why “water absorption” is not considered a function of the skin.
a. Production of Vitamin D
This is a function of the skin. When the skin is exposed to ultraviolet B (UVB) rays from sunlight, it synthesizes vitamin D3 (cholecalciferol) from cholesterol. This vitamin is essential for calcium absorption, bone health, and immune function.
b. Protection against microbes
This is another key function. The skin acts as a physical barrier, preventing the entry of harmful microorganisms such as bacteria, viruses, and fungi. The acidic pH, natural oils, and the immune cells within the skin (like Langerhans cells) further contribute to this protective role.
c. Water absorption
This is NOT a function of the skin. The skin is designed to be waterproof, largely due to the outermost layer called the stratum corneum, which contains keratin and lipids. This structure prevents water from entering or exiting the body excessively. While skin can absorb very small amounts of moisture, it does not play a significant role in overall body hydration. In fact, one of the skin’s main jobs is to prevent water loss, not absorb water.
d. Temperature regulation
The skin helps regulate body temperature through sweat production and vasodilation or vasoconstriction of blood vessels in the dermis. When the body is hot, sweat is released to cool it down. When cold, blood vessels constrict to conserve heat.
e. Collection of sensory information
The skin contains sensory receptors that detect touch, pressure, pain, and temperature. These receptors send signals to the brain, allowing us to sense our environment.
In summary, while the skin performs numerous vital functions, water absorption is not one of them. Its structure is specifically designed to prevent excessive water entry and loss, which is essential for maintaining fluid and electrolyte balance in the body.