What is the skin?
The skin is the biggest body organ. It is flexible and resistant, capable of withstanding constant external aggressions.
The main functions of the skin are:
- Protection (against infections, sun rays, etc …)
- Regulating body temperature
- Storing water and fat
- Avoiding water loss
- It is a sensory organ
The characteristics of the skin (thickness, color, texture…) are not the same throughout one’s body. Its thickness, for instance, varies between 1.5 and 4 mm depending on the area.
The skin is composed of three layers; epidermis, dermis and hypodermis.
The epidermis is the outer layer that is in contact with the outside. It is not vascularized and the nutrients reach it through the dermis. It is made up of living and dead cells. In the epidermis, keratin is formed, which gives the skin its resistance. In its deepest layer, the cells called melanocytes are responsible for secreting melanin – the pigment that darkens the skin to protect it from the sun’s rays. In this layer, just on the border with the dermis, are the cells responsible for the sense of touch (Merkel cells).
The dermis is the middle layer of the skin. It is composed of blood vessels, lymphatic vessels, hair follicles, sweat and sebaceous glands, nerves, collagen fibers and fibroblasts.
The dermis is held together by the connective tissue or extracellular matrix. The optimal state of the extracellular matrix is very important, since it is the environment where the cells are “immersed”. In this matrix, the cells communicate with each other, move and regenerate. It is formed mostly by collagen, elastin, polymers (hyaluronic acid) and amino acids.
The hypodermis, or subdermis, is the deepest layer of the skin. It consists basically of adipose tissue (collagen and fat cells). This layer is responsible for storing fat for the energy reserve and to protect us from injuries. It is also responsible for regulating and conserving body heat.
Facial skin and body skin
The skin of the face is the most exposed skin of our body and that is why it suffers the most from any type of external aggression. It has a greater number of sebaceous glands than other areas of the body. It is also the area where the skin is more elastic and thin so that we can make different facial expressions.
All kinds of facial skin types must be taken into account: dry, oily, mixed, acne and sensitive.
The skin of the body in general is thicker than the skin of the face, although there are areas such as the neck where the skin is thinner compared to other body areas. The palms of the hands and feet is where we find the greatest thickness.
Most of the time the skin of the body is protected by our clothes and therefore it is less exposed to environmental damage. This means that the first signs of aging are not detected as easily as on the face, unless the exposure to the sun has been excessive and prolonged.