Stratum granulosum

Definition

The stratum granulosum is the third layer of the epidermis, located between the stratum spinosum and stratum lucidum. It plays a crucial role in skin barrier function and water retention.

5 Must Know Facts For Your Next Test

1. The stratum granulosum consists of 3-5 layers of flattened keratinocytes.
2. It contains keratohyalin granules, which are essential for the formation of the skin's waterproof barrier.
3. Cells in this layer begin to die and lose their nuclei as they move upward to form tougher outer layers.
4. Lipids released from these cells contribute to the skin's permeability barrier, preventing excessive water loss.
5. Pharmacologic agents targeting this layer can help treat dermatologic disorders by enhancing or restoring its barrier function.

Review Questions

• What is the primary function of the stratum granulosum?
• How many layers of keratinocytes are typically found in the stratum granulosum?
• Why are keratohyalin granules important for skin health?

Related terms

Stratum Corneum: The outermost layer of the epidermis, composed mainly of dead keratinized cells.

Keratohyalin Granules: Granules within the cells of the stratum granulosum that play a key role in forming a waterproof barrier.

Epidermis: The outermost layer of skin consisting of multiple sub-layers including the stratum basale, spinosum, granulosum, lucidum, and corneum.