In zoology, the epidermis is an epithelium (sheet of cells) that covers the body of a eumetazoan (animal more complex than a sponge).[1][2] Eumetazoa have a cavity lined with a similar epithelium, the gastrodermis, which forms a boundary with the epidermis at the mouth.[2]

Sponges have no epithelium, and therefore no epidermis or gastrodermis.[2] The epidermis of a more complex invertebrate is just one layer deep, and may be protected by a non-cellular cuticle. The epidermis of a higher vertebrate has many layers, and the outer layers are reinforced with keratin and then die.[3]

References Edit

  1. ^ Ruppert, E.E.; Fox, R.S. & Barnes, R.D. (2004). "Introduction to Metazoa". Invertebrate Zoology (7 ed.). Brooks / Cole. pp. 59–60. ISBN 0-03-025982-7.
  2. ^ a b c Ruppert, E.E.; Fox, R.S. & Barnes, R.D. (2004). "Introduction to Eumetazoa". Invertebrate Zoology (7 ed.). Brooks / Cole. pp. 99–103. ISBN 0-03-025982-7.
  3. ^ Spearman, R.I.C (1973). "Function Adaptation in the Invertebrate Integument". The integument: a textbook of skin biology. Biological structure and function. Vol. 3. CUP Archive. pp. 15–17. ISBN 0-521-20048-2. Retrieved 21 Mar 2010.