Skin Anatomy - What's Under Your Skin
Before starting my article I will like to say a few words about health.
"Every human being is the author of his own health or disease."
"He, who has health, has hope. And he, who has hope, has everything."
"It is health that is real wealth and not pieces of gold and silver."
You are literally covered in skin – in fact about 2 sq metres (21/2 sq yd) of it. It's only about 4 mm (1/8 in) at its thickest, on the soles of your feet, but weighs in total about 4 kg (9 lbs), or 7 per cent of your total body weight.
Your skin protects your internal organs, lets your body breathe, and helps you resist bacteria and infection. It is not, however, simply an inert, squishy envelope which keeps all the really vital bits of your body together: your skin is, in fact, itself an organ. At its most basic level, it protects us but, like our other vital organs, it performs a number of exchange functions, absorbing what's useful to us and secreting what is damaging. However, unlike your other organs, your skin is on permanent display. It is, literally and metaphorically, the face you show to the world. How our skin functions is of almost no day-to-day concern, not least because, for most of us, it does its job perfectly and unremarkably. The pressing concern most of us have is more superficial; we care about how our skin looks.
A clear, smooth, glowingly healthy complexion is the ideal that we all seek. Some of us are lucky enough to have it naturally, others have to actively pursue it. Whether you are trying to improve your complexion or just keep the one you've got, you'll be better able to do so by understanding more of how your skin works, what it's made up of, and what is actually happening when it starts to wrinkle or develop spots.
Your skin's function
Your skin is your protective barrier to harmful external substances such as bacteria, foreign bodies, chemicals and UV light. It also helps to retain your water electrolytes and other essential body fluids.
Skin is your body's heat regulator, cooling you with sweat when hot, and restricting the blood supply to the extremities when it is cold. And by sending out pain signals, it helps safeguard you from potentially fatal injury.
The Skin's Structure
Your skin is made up of three distinct layers: the epidermis (top layer), the dermis (the middle layer) and the subcutis (the bottom layer).
The epidermis
This is the highly metabolically active top layer in which skin cells and pigment are ‘manufactured'. The horny outer layer is the stratum corneum.
From their place of origin in the lower epidermis, new cells go on a month-long journey towards the surface. For the first two weeks, as they travel through the living epidermis, these cells are round, plump and with a fully functioning nucleus. But as they near the summit, they shriveland flatten out the nucleus begins to break down and they fillwith a tough protein called keratin. This process is called cornification. By the time the cells reach the surface they are flat, scaly, desiccated versions of their former selves. And as such, they are perfectly poised to fulfill their final role — that of protecting you from the outside world.
What you see when you look at your skin is the stratum corneum. It is made up from between 18 to 23 layers of these flat dry skin cells cemented together into a defensive wall by a cocktail of fatty compounds such as lipids, peptides, ceramides and sebum. The primary function of any skincare regime is to keep this wall as solid as possible. It is your best bet for great looking, problem-free skin. Unfortunately, however, the stratum corneum is relatively easily damaged — by the sun's rays and also by the detergents and surfactants we use for cleansing.
As new cells push up to the skin's surface from beneath, the dead scaly ones are invisibly sloughed off to form dust (or fodder for the dust mite). In your lifetime, you will make and lose on average several kg of skin. The process of shedding skin is called desquamation.
Also contained in the epidermis are the spidery-shaped melanocytes, which produce the skin's natural pigment, melanin. Whatever our colouring or race, we all have a similar number of melanocytes. The difference lies in the amount of melanin each produces. Melanin is a dark treacley substance that is manufactured in response to ultraviolet assault. It migrates into individual cells to form a physical umbrella over the nucleus to protect it against sun damage. It is also a fabulously potent neutralizer of skin-ageing free radicals.
The more melanin you produce, the darker your skin and the better protected it is from ultraviolet damage. Very pale skin produces almost no melanin, or if it does, it tends to be a poor-quality variety (phaeomelanin) which often coagulates into all but useless clumps, or freckles. Black skin, on the other hand, produces copious amounts of really useful, and evenly distributed eumelanin. Nevertheless, even the darkest black skins are estimated to offer a natural sun protection factor (SPF) of only about 10.
The dermis
This middle layer is deep and spongy containing collagen and elastin which acts like a supportive, elastic mattress to the epidermis. Up to 3 mm (1/8 in) thick, the dermis is your skin's main foundation. It is an unseen supportive network that forms a firm resilent basis for what sits on top. About 95 per cent of the dermis is made up of collagen, the body's wondrous shock asborber — found everywhere in the body from skin and muscles to tendons and cartilage.
Elastin makes up about 3 per cent of the dermis. As its name implies, it is a stretchy substance, its fibres arranged into springy coils which enables the skin to snap back into place after moving or being pulled.
Hair follicles sit in the depths of the dermis along with sebaceous (or oil) glands and sweat glands. Sebaceous glands are attached alongside the hair follicle, feeding off the same blood supply and using the hair shaft as a natural passageway to get sebum, the skin's natural oil, up to the surface where it spreads out to form a good barrier against moisture loss. Sweat glands have a dual role: firstly, they work to extract excess salts and other toxins, using water to wash them away. Secondly, they help lower a hot body's temperature by releasing liquid onto the skin which evaporates and reduces the heat. A variety of receptor corpuscles are situated in the dermis and are responsible for sensation — touch, vibration, pressure and warm and cold feelings.
The dermis supports and feeds the epidermis with all the nutrients, vitamins and chemicals it needs to produce an effective barrier. It runs the skin's repair, immune and sensory systems, and produces sebum and sweat. It also protects your vital organs from UV damage and injury.
The subcutis
Consisting mainly of fat cells interspersed with blood vessels, bundles of nerve fibres and some fingers of muscle fibre, the subcutis acts as a protective cushion for what lies above and below. It also supports the blood vessels and muscle and nerve fibres. Its depth, not surprisingly, depends on how fat you are; it may be several centimetres deeper over your buttocks while over the eyelids it may be just a few cells thick.
"Every human being is the author of his own health or disease."
"He, who has health, has hope. And he, who has hope, has everything."
"It is health that is real wealth and not pieces of gold and silver."
You are literally covered in skin – in fact about 2 sq metres (21/2 sq yd) of it. It's only about 4 mm (1/8 in) at its thickest, on the soles of your feet, but weighs in total about 4 kg (9 lbs), or 7 per cent of your total body weight.
Your skin protects your internal organs, lets your body breathe, and helps you resist bacteria and infection. It is not, however, simply an inert, squishy envelope which keeps all the really vital bits of your body together: your skin is, in fact, itself an organ. At its most basic level, it protects us but, like our other vital organs, it performs a number of exchange functions, absorbing what's useful to us and secreting what is damaging. However, unlike your other organs, your skin is on permanent display. It is, literally and metaphorically, the face you show to the world. How our skin functions is of almost no day-to-day concern, not least because, for most of us, it does its job perfectly and unremarkably. The pressing concern most of us have is more superficial; we care about how our skin looks.
A clear, smooth, glowingly healthy complexion is the ideal that we all seek. Some of us are lucky enough to have it naturally, others have to actively pursue it. Whether you are trying to improve your complexion or just keep the one you've got, you'll be better able to do so by understanding more of how your skin works, what it's made up of, and what is actually happening when it starts to wrinkle or develop spots.
Your skin's function
Your skin is your protective barrier to harmful external substances such as bacteria, foreign bodies, chemicals and UV light. It also helps to retain your water electrolytes and other essential body fluids.
Skin is your body's heat regulator, cooling you with sweat when hot, and restricting the blood supply to the extremities when it is cold. And by sending out pain signals, it helps safeguard you from potentially fatal injury.
What is Under Your Skin?
The Skin's Structure Your Skin's Construction
Your skin is made up of three distinct layers: the epidermis (top layer), the dermis (the middle layer) and the subcutis (the bottom layer).
The epidermis
This is the highly metabolically active top layer in which skin cells and pigment are ‘manufactured'. The horny outer layer is the stratum corneum.
From their place of origin in the lower epidermis, new cells go on a month-long journey towards the surface. For the first two weeks, as they travel through the living epidermis, these cells are round, plump and with a fully functioning nucleus. But as they near the summit, they shriveland flatten out the nucleus begins to break down and they fillwith a tough protein called keratin. This process is called cornification. By the time the cells reach the surface they are flat, scaly, desiccated versions of their former selves. And as such, they are perfectly poised to fulfill their final role — that of protecting you from the outside world.
What you see when you look at your skin is the stratum corneum. It is made up from between 18 to 23 layers of these flat dry skin cells cemented together into a defensive wall by a cocktail of fatty compounds such as lipids, peptides, ceramides and sebum. The primary function of any skincare regime is to keep this wall as solid as possible. It is your best bet for great looking, problem-free skin. Unfortunately, however, the stratum corneum is relatively easily damaged — by the sun's rays and also by the detergents and surfactants we use for cleansing.
As new cells push up to the skin's surface from beneath, the dead scaly ones are invisibly sloughed off to form dust (or fodder for the dust mite). In your lifetime, you will make and lose on average several kg of skin. The process of shedding skin is called desquamation.
Also contained in the epidermis are the spidery-shaped melanocytes, which produce the skin's natural pigment, melanin. Whatever our colouring or race, we all have a similar number of melanocytes. The difference lies in the amount of melanin each produces. Melanin is a dark treacley substance that is manufactured in response to ultraviolet assault. It migrates into individual cells to form a physical umbrella over the nucleus to protect it against sun damage. It is also a fabulously potent neutralizer of skin-ageing free radicals.
The more melanin you produce, the darker your skin and the better protected it is from ultraviolet damage. Very pale skin produces almost no melanin, or if it does, it tends to be a poor-quality variety (phaeomelanin) which often coagulates into all but useless clumps, or freckles. Black skin, on the other hand, produces copious amounts of really useful, and evenly distributed eumelanin. Nevertheless, even the darkest black skins are estimated to offer a natural sun protection factor (SPF) of only about 10.
The dermis
This middle layer is deep and spongy containing collagen and elastin which acts like a supportive, elastic mattress to the epidermis. Up to 3 mm (1/8 in) thick, the dermis is your skin's main foundation. It is an unseen supportive network that forms a firm resilent basis for what sits on top. About 95 per cent of the dermis is made up of collagen, the body's wondrous shock asborber — found everywhere in the body from skin and muscles to tendons and cartilage.
Elastin makes up about 3 per cent of the dermis. As its name implies, it is a stretchy substance, its fibres arranged into springy coils which enables the skin to snap back into place after moving or being pulled.
Hair follicles sit in the depths of the dermis along with sebaceous (or oil) glands and sweat glands. Sebaceous glands are attached alongside the hair follicle, feeding off the same blood supply and using the hair shaft as a natural passageway to get sebum, the skin's natural oil, up to the surface where it spreads out to form a good barrier against moisture loss. Sweat glands have a dual role: firstly, they work to extract excess salts and other toxins, using water to wash them away. Secondly, they help lower a hot body's temperature by releasing liquid onto the skin which evaporates and reduces the heat. A variety of receptor corpuscles are situated in the dermis and are responsible for sensation — touch, vibration, pressure and warm and cold feelings.
The dermis supports and feeds the epidermis with all the nutrients, vitamins and chemicals it needs to produce an effective barrier. It runs the skin's repair, immune and sensory systems, and produces sebum and sweat. It also protects your vital organs from UV damage and injury.
The subcutis
Consisting mainly of fat cells interspersed with blood vessels, bundles of nerve fibres and some fingers of muscle fibre, the subcutis acts as a protective cushion for what lies above and below. It also supports the blood vessels and muscle and nerve fibres. Its depth, not surprisingly, depends on how fat you are; it may be several centimetres deeper over your buttocks while over the eyelids it may be just a few cells thick.
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