DEFINITION of 'Commercial'. Relating to commerce. In the investment field, the term commercial is generally used to refer to a trading entity engaged in business activities that are hedged by positions in the futures or options markets.
The melanocortin 1 receptor controls which type of melanin is produced by melanocytes. When the receptor is activated, it triggers a series of chemical reactions inside melanocytes that stimulate these cells to make eumelanin. If the receptor is not activated or is blocked, melanocytes make pheomelanin instead of eumelanin.
Melanocytes produce melanin. Keratinocytes are old and stuck together by lots of desmosomes. Langerhans cells part of the immune system, protects micros. Merkel cells the least amount of cells located in the deepest layer of epidermas, acts as a sensory receptor.