Question

Difference between exposed and unexposed cells

Answer 1

The fine structural organization of the epidermis, dermal-epidermal junction, and papillary dermis from unexposed (upper inner arm) and exposed (dorsal forearm) sites of elderly people was compared to the organization of similar regions of young people. Despite an overall thinning of the viable epidermis there was no morphological evidence that the protective function of the epidermis was compromised by age. The differentiation products associated with the keratinization process were not altered in either appearance or amounts in epidermis from unexposed and exposed old skin. Both sites revealed the presence of a well-formed stratum corneum that was the same thickness as that of the young donors. Unexposed and exposed senile skin displayed a relatively flat dermal-epidermal junction devoid of the micro projections of basal cells into the dermis, an indication of a tissue less resistant to shearing forces. Marked elastogenesis, as evidenced by large amounts of 8- to 11-nm (diameter) microfilaments and fibroblasts containing dilated cisternae of rough endoplasmic reticulum filled with flocculent material, was characteristic of the papillary dermis from unexposed and nonactinically damaged exposed old skin. Conversely, in the papillary dermis (Grenz zone) of actinically damaged senile skin the microfilaments were replaced by densely packed collagen fibrils in a colinear arrangement, pre-dominantly parallel to the skin surface. That this dermal architecture was similar to that seen in various scar tissues suggests the Grenz zone is a microscar.

Answer 2

Answer:

exposed cells meaning the cell which make food with the process of photosynthesis and non exposed cell means cells which are not using the process of photosynthesis.