Which one of the following is responsible for regeneration of epidermal cells?

Appeared in: NVS Staff Nurse - 2022

Explanation

Keratinocytes are the most abundant cells in the epidermis, making up about 90% of the cell population.
The primary function of keratinocytes is to form a protective barrier against environmental damage, UV radiation, and pathogens.
Specifically, the keratinocytes in the deepest layer, the stratum basale (also known as stratum germinativum), are stem cells.
These basal keratinocytes are responsible for the constant regeneration of the epidermis through mitotic division, replacing cells that are shed from the surface.

Option A: Merkel's cells are specialized mechanoreceptors involved in the sensation of light touch. They do not have a regenerative function.
Option C: Melanocytes are responsible for producing the pigment melanin, which gives skin its color and protects it from UV radiation. They do not regenerate the epidermis.
Option D: Langerhans cells are immune cells (a type of dendritic cell) that act as the skin's first line of defense, identifying and presenting antigens to the immune system. They are not involved in epidermal regeneration.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Functions of Epidermal Cells as background academic context rather than a clinical decision trigger.
Understanding epidermal regeneration is fundamental to wound healing. When the skin is injured, the migration and proliferation of keratinocytes from the wound edges and hair follicles are crucial for re-epithelialization and closing the defect.
In procedures like split-thickness skin grafts, the donor site heals because the basal keratinocytes from the remaining portions of hair follicles and sweat glands proliferate to form a new epidermis.
What if? - If a burn destroys the entire epidermis including the stratum basale and the dermal appendages (a full-thickness burn), the skin cannot regenerate on its own. This is because the source of keratinocyte stem cells is lost, necessitating skin grafting for healing.

How to Approach the Question

First, identify the key concept in the question stem: 'regeneration of epidermal cells'. This directs you to think about cell division and renewal in the skin.
Next, recall the main types of cells found in the epidermis and their primary functions.
Evaluate each option:
Merkel's cells are for touch.
Melanocytes are for pigment.
Langerhans cells are for immunity.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 1232-1234

Practise the full NVS Staff Nurse - 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.