Thick skin - present on fingertips, palms, and soles of feet, it is specialized for protection from friction and contains many sensory receptors, associated cell types and structures.

Examine a section of thick skin (sample 1 and sample 2) and identify epidermis and dermis.

• In the dermis, note the difference between the papillary and reticular layers.
• Note, too, how downward epidermal folds or ridges interdigitate with upward projecting dermal papillae.
• In the epidermis, identify characteristic cells, keratinocytes,  representing the
  • Stratum basale,
  • Stratum spinosum,
  • Stratum granulosum, and
  • Stratum corneum
  • Click image to right for expanded view.
• The strata grade into one another and cells gradually move outward from the basal layer to the cornified layer.

Note he ultrastructural features of the intercellular connections of the keratinocytes.Desmosomes are extraordinarily abundant in the stratum spinosum, helping hold adjacent cells, as well as the layers of cells together. Desmosomes are integrated with the high molecular weight keratin intermediate filament network, and together, these help the epidermis resist mechanical strains such as friction. (Image from Junqueira’s Basic Histology 14th edition)
 

The skin as a route of medication delivery.