How do the cells of the stratum granulosum receive nutrients and oxygen?

• A. Via active transport from the epidermal surface
• B. By phagocytosis of surrounding cells
• C. By diffusion from blood vessels in the underlying dermis
• D. Through direct blood supply within the stratum granulosum

Answer: (C)

Verified step by step guidance

1. Understand the structure of the skin: The skin is composed of two main layers, the epidermis (outer layer) and the dermis (inner layer). The stratum granulosum is part of the epidermis, which is avascular (lacks blood vessels).
2. Recognize the role of the dermis: The dermis contains blood vessels that supply nutrients and oxygen to the skin. These nutrients and oxygen diffuse upward into the avascular epidermis.
3. Learn about diffusion: Diffusion is the passive movement of molecules from an area of higher concentration (blood vessels in the dermis) to an area of lower concentration (cells in the epidermis). This process does not require energy.
4. Clarify why other options are incorrect: Active transport requires energy and is not the mechanism for nutrient delivery in this case. Phagocytosis involves engulfing particles, which is not relevant here. The stratum granulosum does not have a direct blood supply, as it is part of the avascular epidermis.
5. Conclude that the cells of the stratum granulosum receive nutrients and oxygen by diffusion from blood vessels located in the underlying dermis.