BrainStuff How Does the Skin Barrier Work?
Nov 25, 2025
Skin acts like castle walls, defending against microbes and UV light. Explore the different layers, including the stratum corneum which forms a flexible, waterproof barrier. Discover how skin retains moisture while preventing water loss, and how monthly cell turnover helps shed invaders. Learn about the immune cells that protect us, the effects of inflammation, and what disrupts this vital barrier. Additionally, delve into conditions like psoriasis and how to maintain skin health as we age, emphasizing gentle care and sun protection.
AI Snips
Chapters
Transcript
Episode notes
Skin As A Castle Wall
- The skin acts like a castle wall with a physical and immune barrier protecting against microbes and UV light.
- The outer epidermis, especially the stratum corneum, provides the primary physical defense despite being microscopic and thin.
Dead Cells Form A Waterproof Wall
- The stratum corneum is a flexible brick wall of dead corneocytes bound by lipid mortar that makes skin waterproof.
- This structure preserves body water and blocks water-based germs despite being only 10–20 micrometers thick.
Corneocyte Death Is Functional
- Corneocytes contain keratin and water-attracting components so skin stays pliable without becoming overly moist.
- Their programmed death prevents infection and allows continual sloughing to remove microbes.