RT Book, Section
A1 Proksch, Ehrhardt
A1 Jensen, Jens-Michael
A2 Goldsmith, Lowell A.
A2 Katz, Stephen I.
A2 Gilchrest, Barbara A.
A2 Paller, Amy S.
A2 Leffell, David J.
A2 Wolff, Klaus
SR Print(0)
ID 56034571
T1 Chapter 47. Skin as an Organ of Protection
T2 Fitzpatrick's Dermatology in General Medicine, 8e
YR 2012
FD 2012
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-166904-7
LK accessmedicine.mhmedical.com/content.aspx?aid=56034571
RD 2024/04/19
AB |PrintSkin  Barrier  at  a  GlanceThe  most  important  function  of  the  skin  is  to  form  a  barrier  between  the  organism  and  the  environment.The  skin  barrier  prevents  excessive  water  loss  (inside–outside  barrier)  and  the  entry  of  harmful  substances  from  the  environment  (outside–inside  barrier).The  physical  barrier  is  predominantly  located  in  the  stratum  corneum.The  stratum  corneum  barrier  is  composed  of  corneocytes  and  intercellular  lipids,  cholesterol,  free  fatty  acids,  and  ceramides.Keratins  and  cornified  envelope  proteins  are  important  for  the  mechanical  stability  of  the  corneocytes.The  cornified  envelope  protein  involucrin  binds  ceramides  covalently,  forming  a  backbone  for  the  subsequent  attachment  of  free  ceramides.The  nucleated  epidermis  through  tight  junctions  and  desmosomes  also  contributes  to  the  barrier.Experimental  barrier  disruption  increases  epidermal  lipids  and  changes  in  epidermal  differentiation.The  signals  for  barrier  recovery  are  cytokines  and  the  calcium  ion  gradient.Several  diseases  are  characterized  by  a  probably  genetically  disturbed  barrier  function.  The  disturbed  barrier  function  contributes  to  disease  pathology,  in  particular  in  contact  dermatitis,  atopic  dermatitis,  forms  of  ichthyosis,  and  psoriasis.Lipid  or  lipid-like  creams  and  ointments  can  repair  disturbed  barrier  function.