The skin, which is the uppermost layer of our body, is made up of tissue consisting mainly of three layers:
The purpose of the skin is to protect the body from the external environment and receive sensory stimuli. It covers the internal organs from shocks and wounds and acts as the first layer of defence against germs, viruses, insects etc.
One of the characteristic features of skin is that it continues to change from birth to old age. The skin is very dry, velvety, soft, and free of wrinkles and blemishes in infants and children, while at old age, the skin becomes rough, rugged and full of wrinkles.
Human beings lack body hair which distinguishes them from other land mammals. However, there are certain areas where hair grows copiously.
Those places are referred to as epigamic areas and are concerned with sexual and social communication. These hair follicles are associated with glands that produce body scents.
The body hair becomes thick, long and more pigmented during adolescence, particularly in the pubic region, male face, scalp, and axillae. The physiological and anatomical changes increase as a person ages. The skin not protected by clothes gets exposed to wind, sunlight, and other natural factors that make the skin wrinkled, dry, and flaccid.
The sebaceous glands are present underneath the skin and are responsible for the production of sweat. The human skin shows topographic differences.
For example, you can notice the dissimilarity in the skin between the back of the hands and fingers with the palm.
You can also notice the eyebrows where the skin is coarse, thick and hairy, whereas the eyelid skin is smooth, thin and covered by minute hairs. Multiple layers of tissue provide flexibility and strength to the skin.
Countless sensory receptors enwrap the skin and help the body to communicate with the environment.
The dermis forms the main component of skin and is responsible for physical protection. An association of fibres forms it, and collagen forms the primary material along with glycosaminoglycans. These materials can hold huge amounts of water, which helps maintain the turgidity of the skin.
Extendable elastic fibres help the skin to stretch and return to its normal shape. The skin glands and hair follicles are found in the epidermis. There is a rich supply of blood vessels and contains sense organs and nerves at different levels in the dermis.
There is an abundant supply of blood vessels in the human skin in veins, arteries and capillaries. This excess supply of blood functions as a cooling system at the disposal of the blood vascular system.
There are sweat glands present too that helps in cooling the body by pouring water over the surface that evaporates, absorbing the body heat.
When the environment is cold, the body conserves warmth, and there is a quick contraction in the cutaneous blood vessel, resulting in a small amount of blood flow.
In contrast, the cutaneous blood vessel contract at long intervals to allow maximum blood flow. The blood flow is full when the body heats up excessively during physical exertion. The skin also regulates blood pressure by controlling the flow of blood through sphincter like vessels.
Underneath the skin is a mesh of lymph vessels. These vessels form a net that runs under the skin and terminates in blind sacs. The lymph vessels lack muscles, and as a result, the lymph circulation is slow and mainly controlled by external forces such as massaging, pressure, skeletal muscle action etc.
Hair follicles and sweat glands cover the surface of the skin. The intersecting lines in the skin create furrows that follow a characteristic pattern. The markings are almost similar in every individual, but the details are unique.
The countless number of lines that follow elastic tension form characteristic topography in the body. Such details are unique to every individual, and as a reason, fingerprints are used as personal identification because of clear patterns, high relief and are easy to obtain. Sometimes damages on the skin create marks or lines on the surface.
The epidermis or the surface of the skin has a varying thickness on different parts of the body. The layer of epidermis at the soles and the palm are thick. The lower layer consists of living cells along with a layer of compact dead cells.
There are many divisions in the skin layer. The uppermost layer of the epidermis is made up of keratin. The purpose of the epidermis is to protect and act as a barrier to the external environment preventing allergens and irritants.
The epidermis layers are stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale. The epidermis consists of melanocytes that produce melanin, which saves us by absorbing harmful UV radiation. The size and number of melanocytes determine the colour of the skin.
Following the epidermis is the base membrane, also called the dermo-epidermal junction. This layer joins the epidermis with the dermis. The layer of the dermis is made up of collagen and are an association of fibres.
The dermis layer is much thicker than the epidermis and plays the role of providing support and support to the epidermis. It also helps in cushioning external shocks and protecting the internal organs from injury. The dermis also undertakes to heal.
Beneath the dermis is the hypodermis or the subcutaneous layer, which is composed of fat. It is responsible for structural support as well as maintaining body heat and absorbing shocks. This layer consists of numerous nerves and blood vessels.
Pigmentation of the skin is the colour of our skin due to the amount of melanin which is a natural pigment present in our skin, eyes and hair and gives it a unique colour. The production of melanin is responsible for the darker or lighter body colour.
The colour also varies for many factors, such as excessive exposure to the sun and acne or related to the genes an individual is born with. The production of melanin is undertaken by a particular type of cells called melanocytes.
The two types of melanin produced are as follows:
The other name of the sweat gland is sudoriparous glands, tiny tubular structures underneath the skin that produce sweat. These type of glands are known as exocrine glands and produce or secrete substances through ducts.
The base of the gland is located in the lower region of the dermis and hypodermis.
Adipose tissues surround the sweat glands. The secretory product is produced by special coils called secretory coils and is controlled by the autonomic nervous system.
The amount of sweat glands is different for every individual and is different for other areas.
There are sweat glands present everywhere in the body except the ear canal, lip, glans penis, clitoris and labia minora.
Now, sweat is nothing but mostly water, along with some electrolytes. It tastes salty because of the presence of sodium chloride. The volume of sweat produced depends on the number of functional glands and the surface area of the opening.
When all the sweat glands work at total capacity, it is estimated that the perspiration rate may exceed three litres per hour.
Skin type varies from person to person, and individuals need to know their type of skin. The different types of skin are as follows:
Skin is the biggest organ in the body and is responsible for protecting internal organs, muscles and bones. It acts as the first barrier between the body and pathogens. It helps in regulating temperature and synthesizes vitamin D. So we should take care of our skin.
Nanotechnology is the future of skincare and plays a significant role in protecting the skin. Skincare products are already containing nanoparticles and nanocarriers. Companies are introducing nanotechnology in lotions and creams as a new approach to skincare. It helps in improving sunscreen and delivers molecules through the skin.
As per the study, skin diseases are ranked as the fourth most ordinary cause of human illness, and many people do not even consult a doctor. A study was conducted on 2,701 individuals, and it was observed that there were at least one skin abnormality in 1,662 (64.5%) participants.
The most common diseases observed were actinic keratosis (26.6%), rosacea (25.5%), and eczema (11.7%). It was also observed that skin diseases also increase with increasing age, and it is most often in men (72.3%) than women (58.0%). Many participants were even unaware of the abnormal skin findings.