What is the primary role of lamellated granules in the stratum granulosum of the epidermis?

• A. They secrete lipids that contribute to the skin's barrier function and prevent water loss.
• B. They produce melanin to protect against ultraviolet radiation.
• C. They initiate immune responses against invading pathogens.
• D. They synthesize keratin fibers for structural support.

Answer: (A)

Verified step by step guidance

1. Understand the structure of the epidermis: The epidermis is the outermost layer of the skin, composed of several sublayers. The stratum granulosum is one of these layers, located between the stratum spinosum and the stratum corneum.
2. Learn about lamellated granules: These are specialized organelles found in the cells of the stratum granulosum. They contain lipids and other substances that are secreted into the extracellular space.
3. Explore the function of lamellated granules: The lipids secreted by lamellated granules form a hydrophobic barrier, which is crucial for preventing water loss and maintaining the skin's protective function.
4. Differentiate the roles of other components: Melanin production occurs in melanocytes, not lamellated granules. Immune responses are initiated by Langerhans cells, and keratin synthesis is primarily carried out by keratinocytes in other layers of the epidermis.
5. Conclude the primary role: Lamellated granules are specifically involved in secreting lipids that contribute to the skin's barrier function and prevent water loss, distinguishing their role from other processes in the epidermis.