The Skin Bible: Skin Science (Part 4)

SkinScience 2

So far we have talked about skin types, skin disorders and the basics of a good skin routine. This post will really delve into the science of skin. Knowing the function and physiology of your skin will not only help you appreciate how important it is to take care of your skin but will also help you understand how and why skincare works, meaning you will hopefully be able to make more informed choices with your routine.

Skin Function

Did you know the skin is the largest organ of the body? Not only is this a handy piece of trivia to know but it means its really important to take care of it. It protects the body from harmful elements in the environment such as UV radiation, foreign substances, bacteria and harmful chemicals. It continually helps eliminate wastes and secrets protective lubricants.

Time for more trivia? The skin makes up around 15% of your body weight, each square centimetre has 6 million cells, 5000 sensory points, 100 sweat glands and 15 sebaceous glands. The following are some key functions of the skin:

Sensation the nerve endings in the skin identify touch, heat, cold, pain and light pressure.

Heat Regulation the skin helps regulate the body temperature by sweating to cool the body down when it overheats and shivering creating ‘goose bumps’ when it is cold. Shivering closes the pores. The tiny hair that stands on end traps warm air and helps keep the body warm.

Absorption absorption of ultraviolet rays from the sun helps to form vitamin D in the body, which is vital for bone formation. Some creams, essential oils and medicines (e.g. HRT, anti-smoking patches) can also be absorbed through the skin into the blood stream.

Protection the skin protects the body from ultraviolet light – too much of it is harmful to the body – by producing a pigment called melanin. It also protects us from the invasion of bacteria and germs by forming an acid mantle (formed by the skin sebum and sweat). This barrier also prevents moisture loss.

Excretion waste products and toxins are eliminated from the body through the sweat glands. It is a very important function which helps to keep the body ‘clean’ from the inside.

Skin Physiology

Skin is made of three main parts: the epidermis, the dermis and the hypodermis. The main function of the epidermis is to form a tough barrier against the outside world. Dead skin cells are continually shed from the epidermal surface. This is balanced by the dividing cells in the bottom layer of the epidermis to produce a state of constant renewal. The dermis is a soft, thick cushion of connective tissue that lies directly below the epidermis and largely determines the way our skin looks. It also keeps repairing and renewing itself, but the dermis does it more slowly than the epidermis. Under the dermis is a layer of fat cells, which is known as the hypodermis (or subcutaneous fat layer). It provides insulation and protective padding for the body

Skin Anatomy  

Skin Anatomy

The dermis contains sebaceous glands, sweat glands, hair follicles and a small number of nerve and muscle cells.

Sebaceous Glands are based around hair follicles and produce sebum, an oily protective substance that lubricates the skin and hair and provides protection.

Sweat Glands originate in the subcutaneous fat and produce a mixture of water, salts and toxins (sweat). This mixes with sebum to form an acid mantle which sits over the top of the epidermis and protects the skin.

Pores and Hair Follicles a pore is the opening of the hair follicle onto the surface of the skin. The source of hair follicle lies deep within the dermis. Midway up the dermal layer, the sebaceous oil gland empties into the hair follicle. Both sebum and the hair get to the surface through these tine pores.

Nerves nerve fibres are attached to different types of skin receptors that can pick up different stimulus (heat, cold, pain, touch). The nerves are then able to send chemical messages to the brain which can then direct your body to respond in the appropriate way.

Capillaries and Lymphatics the dermis also contains capillaries (tiny blood vessels) and lymph nodes which produce immune cells. Blood capillaries are responsible for bringing oxygen and nutrients to the skin and removing carbon dioxide and products of cell metabolism. Lymph nodes are engaged in protecting the skin from invading organisms.

Melanocytes located in the bottom layer of the epidermis are cells called melanocytes that produce melanin. Melanin is a pigment absorbed into the dividing skin cells to help protect them against sun damage. The amount of melanin in your skin is determined by your genes and by how much exposure to sunlight you have. The more melanin pigment present, the darker the colour of your skin.

Collagen and Elastin critically important skin proteins in the dermis: collagen is responsible for the structural support and elastin for the resilience of the skin. When the skin is younger, these two fibres are bound together tightly in a mashed web but as the skin ages this becomes looser and causes skin sagging and deeper wrinkles.  

So there you have it. The basic 101 on Skin Science. I mean, obviously it is not all there is to it considering dermatology is an entire medical speciality, but as a beauty enthusiast or skin-caretaker this is all you really need to know.

The next post is the one I am most excited for and will explore what all those fancy ‘active ingredients’ in skin care products actually do and whether you personally really need all of them. Before I finish up I would like to thank everyone for the support and would really appreciate if you could share this series around if you found it useful or enjoyable.

I am also happy to give you personalised skin advice if you just contact me via this blog, my facebook or instagram account which you can find to the right of this post. I am really proud of this series and I have all my readers to thank for its success. xox your local bohemian

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