American Academy of Professional Coders (AAPC) Practice Exam

The stratum Granulosum is essential for what primary function?

1. Hair growth

2. Skin cell regeneration

3. Water retention in the skin

4. Protection against pathogens

The correct answer is: Water retention in the skin

The stratum granulosum, a layer of the epidermis, plays a critical role in water retention within the skin. This layer is characterized by the presence of keratinocytes that are undergoing a process called keratinization, where they fill with keratin and begin to lose their nuclei. The cells in the stratum granulosum produce and secrete a lipid-rich substance that creates a barrier, effectively helping to prevent water loss from the skin. This moisture barrier is crucial for maintaining skin hydration, which is vital for overall skin health and function. By retaining water, the stratum granulosum helps to keep the skin supple and prevents it from becoming dry and flaky. Other layers of the skin, while they serve important functions—such as protecting against pathogens, facilitating skin cell regeneration, or allowing for hair growth—are not primarily focused on water retention like the stratum granulosum is. The unique composition and function of this layer make it essential for maintaining the skin’s moisture balance.