Dermatology Basics: Layers of Skin

Study Notes

Layers of Skin

The skin consists of various layers, each with distinct functions and structures.
The epidermis is the outermost layer and contains several subdivisions.

Structure of the Epidermis

Stratum Corneum:
- Composed of dead, flat cells with no nuclei.
- Found predominantly in the palms and soles, providing a protective barrier.
Stratum Lucidum:
- Contains refractile granules of Eleidin, a precursor to keratin.
- Mainly present in thick skin areas.
Stratum Granulosum:
- Characterized by keratohyalin granules that produce Filaggrin, essential for skin hydration.
- Acts as a barrier to water loss.
Stratum Spinosum:
- Contains dendritic cells, which play a crucial role in immune response.
- Provides strength and flexibility through desmosomes that attach keratinocytes.
Stratum Basale (Stratum Germinativum):
- The innermost layer, highly mitotically active (proliferating).
- Responsible for generating new cells that migrate to the surface.

Basement Membrane

Serves as a structural foundation separating the epidermis from the dermis.
Provides support and facilitates nutrient exchange.

Keratin Synthesis

Keratinocytes undergo keratin synthesis, crucial for skin strength and barrier function.

Epidermal Turnover Time (ETT)

ETT refers to the duration for keratinocytes to move from the stratum basale to shedding, typically takes about 8 weeks (42-75 days).
In conditions like psoriasis, epidermal turnover is significantly accelerated at just 4 days.

Description

Explore the fundamental concepts of dermatology, focusing on the layers of the skin. This quiz covers the structure of the epidermis, including details about the stratum corneum, stratum lucidum, and other key components such as dendritic cells and melanozytes. Test your knowledge on the important features and functions of these skin layers.