New skin cells are produced in the
A stratum basale.
B cutaneous membrane.
C stratum corneum.
D dermis.
The correct answer and explanation is:
Correct Answer: A. Stratum basale
Explanation (300 words):
New skin cells are produced in the stratum basale, which is the deepest layer of the epidermis, the outermost portion of the skin. This layer, also called the basal layer or germinativum, is a single row of columnar basal cells that constantly divide through mitosis to form new keratinocytes, the primary cell type in the epidermis.
These new keratinocytes are pushed upward into the upper layers of the epidermis as new cells form beneath them. As they move upward, they undergo changes: they fill with the protein keratin, flatten out, lose their nucleus, and eventually die. This process is called keratinization. The topmost layer, the stratum corneum, is made up of these dead, flattened cells that provide a tough, protective barrier.
Let’s look at the other options to understand why they are incorrect:
- B. Cutaneous membrane refers to the entire skin—both the epidermis and the dermis. While it includes the region where skin cells are made, it is too broad a term and not specific to where new cells originate.
- C. Stratum corneum is the outermost layer of the epidermis. It contains dead, keratinized cells and does not produce new cells.
- D. Dermis is the layer beneath the epidermis and contains blood vessels, nerves, hair follicles, and glands, but not the cells that divide to make new skin cells.
In summary, the stratum basale is the specific layer where new skin cells are generated. These cells gradually move toward the surface, playing a vital role in the skin’s ability to regenerate and protect the body.