EpidermisThis is the outer layer of the skin. The epidermis has four distinct layers and where the skin is thick e.g. on the palms of the hand, it has five layers. The four types of cells in the epidermis are:
- Keratinocytes - produce the protein called keratin, which helps waterproof and protect the skin.
- Melanocytes - produce the pigment melanin, which contributes to skin colour and protects against UV light.
- Langerhans cells - interact with white blood cells in immune responses have an important role in the skin immune system. They detect any foreign matter threatening the skin and cause a response, such as allergies. The Langerhans' cell are closely connected to the nervous system. This is evident with people who skin problems (such as acne) are worse when the person is stressed.
- Merkel cells - function in the sensation of touch.
The deeper layer, the dermis is composed of connective tissue containing collagen and elastic fibres. Blood vessels, nerves, sweat glands, sebaceous glands, and hair follicles are embedded in the dermis.