The skin is the body's first line of defense. As well as keeping everything in, your layers of skin protect the body from outside environment influences, such as bacteria, liquid, sunlight, gases etc. The skin also plays an essential role in temperature regulation; the sense of touch and controlling substances entering and leaving the body.
Continuous regeneration of the skin means that it has incredible healing powers. If we cut, bruise or burn our skin, the fact that it has a continuous cycle of healing, shedding and cell regeneration allows healing to take place.
Epidermis
This 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.
Dermis
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.
Subcutaneous Layer
Also known as the hyperdermis, it consists primarily of adipose tissue. It is important in stabilising the position of the skin in relation to underlying tissues.
