hudskiktet

Hudskiktet, also known as the epidermis, is the outermost layer of the skin in humans and many other vertebrates. It serves as a protective barrier against environmental hazards such as pathogens, chemicals, and physical injuries. The epidermis is composed primarily of keratinized stratified squamous epithelium, which provides resilience and waterproofing.

This layer of skin is subdivided into several sublayers, with the most prominent being the stratum corneum, consisting of dead, flattened keratinocytes that are continually shed and renewed. Beneath the stratum corneum are living keratinocytes originating from the stratum basale (basal layer), where cell division occurs. As these cells mature, they migrate upward, producing keratin and eventually degenerating into the outermost layer.

The epidermis also contains specialized cells such as melanocytes, which produce melanin responsible for pigmentation and protection against ultraviolet radiation, and Langerhans cells, which play a role in the immune response. The thickness of the hudskiktet varies across different parts of the body, being thicker on palms and soles and thinner on areas like the eyelids.

Its primary functions include acting as a physical barrier, preventing water loss, regulating immune responses, and contributing to thermoregulation. The renewal process of the epidermis typically takes about 28 days, a cycle crucial for skin health and repair. Damage or abnormalities in the hudskiktet can lead to various skin conditions, including infections, psoriasis, and eczema. Due to its essential protective role, maintaining the health of this outermost skin layer is vital for overall skin integrity and health.