Question

The epidermis of the skin consists of many layers of tightly packed cells. The outermost layer of cells are dead. Which best describes why this occurs?
a. Chemical compounds containing digestive enzymes are located on the outside of the skin, and they destroy the cells.
b. Blood vessels are not located in the epidermis, but in the underlying dermal connective tissue.
c. The outer layer of skin is nervous tissue and nervous tissue will not regenerate.
d. Pathogens on the skin secrete toxins that affect the cellular structure, thus destroying the cell.

Answer 1

Answer: d. Pathogens on the skin secrete toxins that affect the cellular structure, thus destroying the cell.

Epidermis is the outermost protective layer of skin. It is composed of two layers, the first is the outer stratum corneum, which is typically composed of dead, keratin filled cells and the second one is the living basal layer, which covers the inner dermal layer of skin. The layer stratum corneum is composed of protein keratin is protective against pathogenic agents. It does not allow the absorption of the toxins secreted by the pathogens.    

Answer 2

"Answer DThe outermost layer of old epidermal cells are sloughed off and replaced every 15 to 30 days. The sebaceous glands secrete sebum which maintains the skin pH between 3 and 5. Bacteria which metabolize sebum live as opportunistic pathogens on the skin and cause skin infections."