EPIDERMIS
(Outermost layer)The epidermis is the thin, protective outer layer of the skin. It acts as a barrier against the environment.
What it contains:
- Keratinocytes: cells that produce keratin, a protective protein.
- Melanocytes: cells that produce melanin, which gives skin its color and helps protect against UV radiation.
- Langerhans cells: immune cells that help detect foreign substances.
- Merkel cells: cells involved in light-touch sensation.
Important facts:
- It does not contain blood vessels.
- New skin cells form in its deepest layer and move toward the surface.
- The outermost cells gradually shed.
The epidermis has five sublayers
The epidermis itself has distinct layers. From the deepest to the most superficial, they are:1
Stratum basale (basal layer)
The deepest epidermal layer. It produces new keratinocytes. Melanocytes and Merkel cells are also found here.
2
Stratum spinosum (prickle-cell layer)
Provides strength and structural support. Keratinocytes connect through structures called desmosomes.
3
Stratum granulosum (granular layer)
Cells begin to break down their internal structures and form a waterproof protective barrier.
4
Stratum lucidum (clear layer)
A thin, clear layer found in thick skin, especially the palms of the hands and soles of the feet. It is absent in most ordinary thin skin.
5
Stratum corneum (horny layer)
The outermost layer. It consists of dead, flattened, keratin-filled cells that protect the body and help prevent water loss.

