Explore The Cells of The Epidermis

A keratinocyte is the primary cell type (about 90%) within the epidermis which is the outermost layer of the skin. The alternate names for keratinocytes are basal cells since they are found in the basal layer (the stratum basale) of the skin.

Melanocytes are second types of skin cells which produce melanin. Melanin is a dark pigment contained inside melanosomes that determines the skin color of the person. They are found in the bottom layer of the skin’s epidermis.

The examples include the middle layer of the eye, the inner ear, meninges, bones, and the heart. Melanin protects against the Ultra-Violet (UV) radiation and support in the immune system.

Langerhans cells are the third type of skin cells also known as dendritic cells (antigen-producing immune cells – APC). These cells contain organelles called Birbeck granules.

Langerhans cells are found in all layers of the epidermis. However, they are most prominent in the stratum spinosum layer (a layer between the stratum granulosum and stratum basale). Examples include blood vessels, the mucosa of the mouth, foreskin, and vaginal epithelium.

These Langerhans cells can also be found in other tissues, such as lymph nodes. Note that while similar in appearance, these langerhans cells’ structures different from the dendrites of neurons.

Merkel cells are also called Merkel-Ranvier cells or tactile epithelial cells. They are oval-shaped cells responsible for light, touch, and sensation and found in the skin of vertebrates.

Merkel cells are in plentiful in highly sensitive skins and make synaptic contacts with somatosensory afferent nerve fibers. Although it is very uncommon, these cells may become malignant and form a Merkel cell carcinoma-an aggressive and difficult to treat skin cancer.

Though it has been found that Merkel cells are derived from neural crest cells, the more recent experiments in mammals have revealed that they are in fact from epithelial in origin.

This is the outer most superficial layer which is made up of 5 inner layers. They are Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, and Stratum corneum.

In general, skin’s epidermal layer is subjected to constant wear & tear from external factors such as sunlight, chemicals such as soaps, and pollution.

Dermis cover the significant portion of the skin’s layer. The dermis layer has connective tissues, blood vessels, oil and sweat glands, nerves, hair follicles, and other structures.

The dermis is made up of two inner layers namely – a thin upper layer called the papillary dermis, and a thick lower layer called the reticular dermis.

Subcutaneous layer is also known as hypodermis. The hypodermis is the innermost layer of the skin. This layer hosts fat and connective tissues that house larger blood vessels and various nerves.

The primary function of the hypodermis is to act as an insulator for regulating the body temperature.

The answer lies hidden in the second layer of the skin (Dermis). The permanent tattoo ink is injected till the dermis layer so that it stays permanent. If it is put on the outer layer, then it will be worn out as time progresses. That is why permanent tattooing is always a harrowing and painful experience.

Here are the main functions of the skin cells:

• Protection: The single most important function of the skin is the protection from the outside environment.
• Keeping Cool: The skin secretes the sweat when the body is hot thus keeping the coolness within by evaporating the sweat from the skin.
• Communication: The skin connects to the nerve fibers to transmit the sensation to/from the brain. (Example: touching a hot or cold surface)
• Reservoir of Nutrients: The skin holds the important fluids and nutrients to keep the skin healthy and functional (Example: Collagen and Elastin).