Skin cells...
A. have terminally differentiated
B. are stem cells
C. become senescent quickly
D. become quiescent quickly
A. have terminally differentiated
The correct answer is A. Skin cells have terminally differentiated.
Terminally differentiated cells are fully specialized cells that have reached their final developmental stage and can no longer divide or change into other cell types. In the case of skin cells, they undergo a process called keratinization, where they become flattened and filled with a protein called keratin, forming a protective layer on the outer surface of the skin. These fully differentiated skin cells, known as keratinocytes, serve the purpose of providing a barrier against external factors and maintaining the integrity of the skin.
Skin cells have terminally differentiated.
To understand why skin cells have terminally differentiated, let's break down the options:
A. Terminally differentiated cells are fully specialized and have lost their ability to divide and differentiate into other cell types. Skin cells undergo a process called differentiation, where they acquire specific features and functions that enable them to serve their role in the skin, such as providing a protective barrier. Once skin cells have completed their differentiation process, they cannot revert back or transform into other cell types, making option A the correct answer.
B. Stem cells are undifferentiated cells that have the potential to develop into different types of specialized cells. While stem cells play a crucial role in tissue regeneration and repair, skin cells themselves are not stem cells. However, the skin does contain a small population of stem cells known as skin stem cells that are responsible for replenishing the skin with new cells.
C. "Senescence" refers to a state where cells undergo irreversible growth arrest and lose their ability to divide. Skin cells do not become senescent quickly. In fact, they have a relatively short lifespan and constantly replenish themselves through the division of skin stem cells.
D. "Quiescence" refers to a reversible state of cellular dormancy, in which cells enter a resting phase where they stop dividing. While skin cells do enter a quiescent state under specific conditions or signals, such as during wound healing or hair growth cycles, they do not become quiescent quickly in general.
In conclusion, the correct answer is A. Skin cells have terminally differentiated.