Dermatology Basics: Layers of Skin

Layers of Skin

• The skin consists of multiple layers, each with distinct structures and functions.

Structure of the Epidermis

• Stratum Corneum:

  • Outermost layer composed of dead, flat cells lacking nuclei.
  • Provides a protective barrier; notably thicker on palms and soles.

• Stratum Lucidum:

  • Present only in thick skin areas (palms and soles).
  • Contains refractile granules of eleidin.

• Stratum Granulosum:

  • Characterized by keratohyalin granules, which produce filaggrin.
  • Contains lamellar granules or Odland bodies that secrete lipids.

• Stratum Spinosum:

  • Contains dendritic cells and is known for its spiny appearance due to desmosomes.
  • Plays a role in intercellular attachment among keratinocytes.

• Stratum Basale (Stratum Germinativum):

  • Innermost layer with high mitotic activity.
  • Responsible for the proliferation of keratinocytes and skin renewal.

Additional Key Points

• Epidermal Turnover Time (ETT):

  • Refers to the duration for keratinocytes to migrate from the stratum basale to shedding, typically around 8 weeks (42-75 days).
  • In conditions like psoriasis, epidermal turnover is significantly accelerated, with a turnover time of just 4 days.

• Desmosomes:

  • Intercellular structures vital for the stability and integrity of the epidermis by enabling attachment between keratinocytes.

Important Terms

• Keratin Synthesis:
  • A crucial process that occurs in the epidermal layers, particularly within the stratum spinosum and stratum granulosum, contributing to skin resilience and protection.

Explore the fundamental layers of the skin in this quiz on dermatology. Test your knowledge on the structure and function of the epidermis, including various strata and their characteristics. Perfect for students and professionals seeking to deepen their understanding of skin anatomy.