Hello lovely steemians welcome to another health segment with me. Today I would be sharing with you about the human skin.
The skin, is the outer protective layer of the body of any living or nonliving things. It is known for covering the entire surface of the body, the most extensive organ in the body and plays a vital role in detecting hot and cold, regulating your body temperature.
Before I proceed to some interesting facts and some diseases of the skin, I would like to list the parts of the skin for easy and clear understanding.
The Mammalian Skin.
The Mammalian skin consist of two major layers which are;
- Outer epidermis,
and - Inner dermis.
**DETAILS.**
Epidermis.
The Epidermis is the outter most part of the skin which is further divided into three layers known as
- Cornified layer
- Granular layer
- Malpighian layer.
Now in details.
Cornified layer.
The Cornified layer is the uppermost layer of the skin and it consists of flat dead cells. It protects the body against against loss of water and entering of foreign bodies. It further more protects the under lying layers from excessive harmful radiation of the sun.
Granular layer.
The granular layer lies beneath the Cornified layer. It consists of living cells. The cells become gradually thickened and longer until they are given up to the Cornified cells.
Malpighian layer.
The malpighian layer is a layer of living cells and where active cell division takes place. This layer, contains dark **melanin pigments ** which gives the skin it's colour.
Now, what is melanin?.
source
Melanin is a complex polymer derived from the amino acid tyrosine.
It is known to be responsible for determining skin and hair colour.
Melanin synthesis.
Numerous steps are involved in the biosynthesis of melanin. The first step is catalysis of the chemical L-3,4-dihydroxyphenylalanine by tyrosinase. A lack of tyrosine can lead to albinism. Tyrosine is only found in a specialized cells called melanocytes, inside which tiny granules of melanin pigment are contained in vesicles called melanosomes.These melanosomes leave the melanocytes and move into other cells in the epidermis. Mostly brown or black in colour, melanin deposits determine the skin pigment which varies depending on the number and distribution of the melanosomes. Aside from determining skin colour, the light absorbent melanin protects the DNA against UV radiation from the sun and it is considered a potential candidate in melanoma treatment. It can be found in several parts of the body like; skin, hair, pupils or irises of the eyes, Stria vascularis of the inner ear and areas of the brain (substantia nigra and locus coeruleus).
Black people are known for having more melanin pigments than the white people. And oriental people are known for having an additional pigments, carotene making their skin yellowish.
As the cells of the malpighian layer divides, they are pushed up and as they move up, they become filled with a substance called keratin(the protein of which hair and nails are composed), becoming flat and dead, thus forming the Cornified layer.
Functions of each cell type in the epidermis layer.
The epidermis layer are made up of four major cell type which are;
Keratinocytes- Which produce keratin as a protective barrier.
Langerhans’ cells- Which present antigens and activate T-lymphocytes for immune protection.
Melanocytes- Which produce melanin, that gives pigment to the skin and protects the cell nuclei from ultraviolet (UV) radiation-induced DNA damage.
Merkel cells- which contains specialised nerve endings for sensation.
The Dermis.
The Dermis is the layer of the skin that lies below the epidermis. It is a thick layer of connective tissues, made up of collagen (mainly), elastin and glycosaminoglycans, which are synthesised by fibroblasts. In togetherness, they provide the dermis with strength and elasticity. The dermis layer consist of sweat glands, sebaceous glands, hair, erector muscles, sensory cells, lymphatic and blood vessels.
•Sweat gland.
Sweat gland is a coiled tube becoming straight as it passes through the dermis and slightly drawn into folds as it goes through the epidermis. It opens onto the surface as a pore. The sweat gland is well supplied with blood capillaries. As blood flows through the blood capillaries, waste products such as water, sodium chloride, small amount of urea area absorbed by the sweat gland. From the sweat gland, the wastes are secreted to the sweat duct and finally to the sweat pores. It secretes waste products in form of sweat from the body. And whenever the sweat evaporates from the skin, it always has a cooling effect on the body.
•Sebaceous gland.
Sebaceous gland is the gland that secretes oily substance (sebum collectively called a pilosebaceous unit)) which lubricates the hair and keeps it flexible. It sebum contains lysozyme which kills bacteria and viruses. It is stimulated by the conversion of androgens to dihydrotestosterone and therefore become active at puberty.
•Hair.
Each hairs of the skin, lies in a deep pit called hair follicle.
There are 3 main types of hair which are;
a) lanugo hair (fine long hair in fetus).
b) vellus hair (fine short hair on all body surfaces).
c) terminal hair (coarse long hair on the scalp, eyebrows, eyelashes and pubic areas).
Each hair consists of modified keratin and is divided into the hair shaft (a keratinized tube) and hair bulb (actively dividing cells, and melanocytes which give pigment to the hair).
Each hair follicle enters its own growth cycle which occurs in three main phases, namely;
a) anagen (long growing phase).
b) catagen (short regressing phase).
c) telogen (resting/shedding phase).
•Erector muscle.
The erector muscle runs on each side of the hair to the base of the malpighian layer. The contraction of the muscles makes the hair to stand up-right and its relaxation flattens the hair.
•Sensory cells.
The sensory cells are made up of five sense receptors in the skin, namely: Touch, pressure, pain, heat and cold receptors. And each receptor is sensitive, to a particular type of stimulus.
•Lymphatic and blood vessels.
The lymphatic and blood vessels supplies food and oxygen to the tissues of the skin. The flowing of the blood in the capillaries helps to determine the amount of heat that is lost from the skin surface by radiation and convention.
Functions of the skin.
1.Protection: The skin protects the body in the following ways:
i) The skin covers and holds the body together.
ii) It forms barrier between external environment and the tissues below.
iii) Prevents harmful bacteria from invading the tissues. The sweat and sebaceous glands have certain constitutes e.g. (lysozyme) in them are antagonistic to invading bacteria.
iv) Protects the body to some extent from physical injuries.
v) It prevents the tissues from drying up.
2.Sensitivity: The skin contains different sense receptors which are sensitive to different environment stimuli. The body can therefore react to changes in the environment. For example, on touching a hot object you quickly withdraw your hand to avoid burning injury.
3.Excretion and osmoregulation: The sweat glands excrete surplus water containing salts and some little amount of waste nitrogenous substance (mainly urea).
4.It manufactures and stores vitamin D.
5.It helps in the maintenance of a suitable constant body temperature.
6..Storage if reserved food: Fats are stored under the dermis. The fats forms an insulating layer.
Amazing And Interesting Facts About The Skin.
source
The average human’s skin covers an area of 2 square meters.
An average adult's skin weighs nine pounds, and contains more than 11 miles of blood vessels.
The skin on the human body's is the largest organ.
The skin renews itself every 28 days.
The skin releases as much as three gallons of sweat a day in hot weather. The areas that don't sweat are the nail bed, the margins of the lips, the tip of the penis, and the eardrums.
The skin accounts for around 15% of your body weight.
The skin constantly sheds dead cells, about 30,000 to 40,000 cells every minute! That’s nearly 9 lbs. per year!.
Body odor comes from a second kind of sweat—a fatty secretion produced by the apocrine sweat glands, found mostly around the armpits, genitals, and anus.
The thinnest skin is found on the eyelids.
Skin can form additional thickness and toughness — a callus — if exposed to repeated friction or pressure.
The breasts are a modified form of the apocrine sweat gland.
The thickest skin is found on your feet.
Some of the nerves in your skin are connected to muscles instead of the brain, sending signals (through the spinal cord) to react more quickly to heat, pain, etc.
We lose around 20-100 hairs a day.
A body hair grows from 2-6 years.
Fetuses don't develop fingerprints until three months' gestation.
Over 50% of the dust in our home is actually dead skin.
The skin has at least five different types of receptors that respond to pain and touch.
Fingerprints increase friction and help grip objects. New World monkeys have similar prints on the undersides of their tails, the better to grasp as they swing from branch to branch.
Every minutes, the skin sheds over 30,000 dead cells.
Fingerprints increase friction and help grip objects. New World monkeys have similar prints on the undersides of their tails, the better to grasp as they swing from branch to branch.
The skin has it's own bacteria microbiome of over 1000 species and around 1,000,000,000,000 individual bacteria.
Acne is caused by an over production of cells that line the sweat gland.
The glands that produces was in our ears are specialised sweat glands.
Boils are caused by the staphylococcal bacteria, which enters through the skin down to the hair follicle.
White skin appeared just 20,000 to 50,000 years ago, as dark-skinned humans migrated to colder climes and lost much of their melanin pigment.
On average, 14 species of fungi lives between your toes.
Fingerprints increase friction and help grip objects. New World monkeys have similar prints on the undersides of their tails, the better to grasp as they swing from branch to branch.
It takes up to 6months for babies to develop their permanent skin tone.
Diseases Of The Skin.
Some skin problem are caused by diseases or irritations that affects the skin only. While some may be signs of unserious disease, some will be signs of serious disease which needs urgent attention.
1)Hives.
source
Hives are thick, raised spots or patches that looks like bee stings and itches seriously. They may come and go rapidly or move from one spot to another.
The skin sometimes becomes extra sensitive to certain things like; food, the poison of bites and stings, heat, cold, pollen and even the effects of nervous upsets. When this over sensitization occurs, the cells if the skin react by producing a poison known as histamine. This poison causes the small blood vessels to dilate and fluid oozes out of them into the skin in spots, which become swollen and itches violently.
The individual must carefully observe the effects of fish, shell fish, cheese, chocolate, onions, garlic, mushrooms, tomatoes, pickles, eggs, citrus fruits, melons, and pork to determine what substance might be producing the condition. Soaps, dogs, cats wool or silk may also be the cause. If the hives are on the exposed skin, the cause may be something that has reached it from the outside. The individual may have been spraying insecticide in the garden or in the house. The individual may also might have been near cows or chickens or in the rice fields during pollinating time or in the fields at harvest time.
All these things must be considered in determining the cause.
Symptom.
- Severe Itching.
Treatment.
Antihistamines, such as anthisan, pyribenzamine or Benadryl should be used. Caladryl lotion should be use in allaying the itching from hives. But most Importantly, the cause of the hive should be discovered and then treated.
2)Eczema herpeticum.
(Kaposi’s varicelliform eruption)
source
It is a widespread eruption serious complication of atopic eczema caused by herpes, simplex and virus. If not treated it do leads to herpes hepatitis, encephalitis, disseminated intravascular coagulation (DIC) and even death.
Symptoms.
It normally begins with extensive crusted papules, blisters and erosion. And systemically, unwell with fever and malaise may occur.
Treatment.
Antivirals (e.g. aciclovir) should be given and proper good hygiene should be practiced.
3)Itch.
source
Itch is caused by the burrowing of a small itch-mite under the skin. It usually invades the skin between the fingers, the skin of the wrist or the skin about the navel and breasts.
Symptoms.
There is usually itching and as a result of scratching, blisters, pimples and red patches are formed. The disease do spread quickly from one member if a family to others in the same family.
Treatment.
The individual having an itching should first of all wash the body thoroughly, using hot water and soap. Then an ointment of mixing three parts of sulphur in seven parts of vaseline or coconut oil should be made, and administered to the skin.
Ascabiol or any other benzyl benzoate emulsion should be used in treatment of itch. To avoid itch, one should not sit, use clothes or towel by the infected person and avoid sleeping on the same bed with someone who has the disease.
4)Psoriasis
source
Psoriasis is a chronic inflammatory skin disease due to hyperproliferation of keratinocytes and inflammatory cell infiltration. It usually affects about 2% of the population in the UK . The most common type is the chronic plaque psoriasis. Some of the causes are; complex interaction between genetic, immunological and environmental factors. Other factors include trauma (which may produce a Köebner phenomenon), infection (e.g. tonsillitis), drugs, stress, and alcohol.
Symptoms
- Demarcated erythematous scaly plaque
- Itchy, burning or painful lesions.
- Capillary bleeding resulting from scratch and removal of scales.
- Nails changes colour.
Treatment.
- Oral therapy, phototherapy and tropical therapy should be administered to the individual of the disease.
5)Ringworm.
source
Ringworm is a skin disease that may develop on any part of the body. It is not caused by a worm but by a fungus that is somewhat similar to the mould that is sometimes seen on a plate of cooked rice that has been allowed to stay overnight.
The disease is caught by coming in contact with the body, or with the clothing, towels or bedding of some person who has ringworm, and it is easily spread.
Symptoms.
The ringworm begins as a small red or brownish spot and spreads out on all sides. After some time the centre of the spot may return to the normal colour of the skin. When this happens the disease presents itself in appearance of a ring, with itching. The itching may be sometimes intense.
Treatment.
Apply Whitefield's ointment by rubbing lightly the affected part.
Incase of ringworm of the scalp, shave the affected places. After shaving off the hair the same treatment should be given too.
For stubborn condition, grisovin in dosages of one table three times a day for about three weeks will clear up the infection. Tincture of iodine applied once or twice will often destroy the infection.
Note, Their are forms of ringworm that are difficult to cure and it's adviceable to consult a physician as soon as possible to prevent the progress of the disease which may even cause baldness.
6)Acne (pimples).
source
The cause of acne is not known, but there seems to be a strong heredity tendency. Acne appears during the adolescent period mostly. For some it's a serious problem, not only medical but also psychological, distrubing even the personality. Sometimes these pimples are very deep and leaves scars somewhat like those of smallpox. Along with acne there are generally a number of comedones (blackheads).
Acne is not caused by diet, but certain foods definitely aggravate this condition, especially in some individuals. Foods such as chocolate, nuts, cola drinks, ice cream, fatty meats, and excessive amount of sugar, all seem to aggravate this condition. Certain drug, such as those containing bromides and iodides, may also play a part in some people.
**Treatment. **
Keep the skin clean by thorough washing two or three times a day with a good mild soap. Some slightly abrasive soap will help to eliminate blackheads, but it should be used with care, particularly if the skin is inflamed. Smaller blackheads may be carefully removed after the use of warm moist towels applied to the face for ten to fifteen minutes. This will make the removal of the blackheads easier. If pus has formed under the skin, be careful not to open the pimple. Squeezing and pinching of the skin may extend the inflammation and delay healing, and may also cause scarring of the face.
Avoid junk foods, excessive amount of sugar, and particularly chocolate. Choose a plain, well balenced diet containing plenty of fresh fruits and vegetables.
7)Scabies.
source
Scabies is a disease mostly common in children. It is caused by little animals- similar to tiny ticks or chiggers- Which make tunnels under the skin. It causes very itchy little bumps that can appear all over the body. And between the bumps are pin-head sized dark scab.
It is commonly found in between the fingers, on the wrists, around the waist and on the genitals. It is spread by touching the affected skin or by clothes and bedding. The scratching can cause infection producing sores with pus and sometimes swollen lymph nodes.
Symptoms.
- Itching and fever.
Treatment.
Personal cleanliness is the first important measures to be taken.
- The individual should bathe regularly.
- Change his or her clothes after each bath.
- Wash all clothes and bedding and hang them in the sun.
- A physician should be seen after that.
General Rules For Treating Skin Problems.
source
Rule1; If the affected area is hot and painful, treat it with heat. Put a hot, moist cloths on it.
Rule2; If the affected area itches, stings or oozes, treat it with cold. Put a cool, wet cloths on it.
Rule3; If the skin areas affected are on parts of the body often exposed to sunlight, protect them from the sun.
Rule 4; If the skin areas most affected are usually covered by clothing, expose them to direct sunlight for like 20 minutes, 2 or 3 times a day.
General Care Of The Human's Skin.
source
Bath regularly with soap to remove dirts, sweat and natural oils from the skin. This prevents bacteria, fungi, mites and dust from sticking to the skin and blocking the sweat pores. Dirty skin causes diseases such as yaws, tinea and scabies.
Dry the washed body with a clean towel.
The feet must be washed frequently and cleaned with towel, and also wearing clean stockings helps to absorb sweat from the clefts of the toes.
Wearing of foot wears like shoes, should be practiced to prevent hookworms and jiggers from infecting the skin and its underlying tissues.
Wearing clean light and loose clothes allows free circulation of air round the body and Prevents discomfort, rashes and fungal infections of the skin.
The skin must be kept moist always by using good creams especially during the harmattan period to keep the skin soft and flexible and also protect it from cracking.
Note: On no account should bleaching creams be used on the skin because, bleached skin is proned to skin infections and cancer.Any signs of skin diseases should be reported quickly to any dermatologist or medical doctor for treatment.
The skin should not be exposed to unnecessary direct radiation of the sun more especially albinos. Direct hot sunlight may cause sunburns.
Avoid eating junk foods, rather eat more of fruits, vegetables, and nuts. For a healthy skin and less prone to acnes.
Drink plenty of water daily to keep the body hydrated and the skin fresh.
Thanks For Reading.
References And Further Reading.
√https://forefrontdermatology.com/skin-fun-facts
√http://discovermagazine.com/2007/feb/20-things-skin
√https://visual.ly/community/infographic/health/50-incredible-facts-about-skin
√Dermatology A handbook for medical students and junior doctors by Dr Nicole Yi Zhen Chiang and Professor Julian Verbov(page 23,24,25,34,50)
√https://www.news-medical.net/health/What-is-Melanin.aspx
√Where There Is No Doctor, by David Werner with Carol Thuman, Jane Maxwel and Andrew Peasron. (Pages 205, 207, 211).
√The New Health And Longevity, by A.C.Selmon M.D. (chapter 35.)
√Idodo Umeh College Biology, by G. IDODO. UMEH, B.Sc (Hons.) M.Sc Phd and PhD. (page 199-202.)
If you write STEM (Science, Technology, Engineering and Mathematics) related post, consider joining #steemSTEM by checking on their blog 
If you are from Nigeria, consider adding #stemng tag in your post and also follow 
Feel free to also use the tag #air-clinic and follow 
