Your Skin: Learning About The Skin You Love
When we talk about organs, what are the first organs that come to the top of your mind?
You might think about the liver, heart, nose, eyes, and ears, and you will be absolutely correct.
But you are forgetting about the largest organ in your body, the skin!!
The skin, being the largest organ in the body, protects against external particles, regulates the temperature of the body and enables the sensation of touch. It also secretes certain enzymes that can kill harmful bacteria. The pigment, melanin, is also produced here which defends against UV light, which damages its cells when exposed to it.
The main layers include the epidermis, dermis, and hypodermis. It is also prone to a plethora of problems which include skin cancer, acne, wrinkles, and rashes.
But let us first dive deep into the definition of skin, itself.
What Is The Skin?
The skin along with the hair, nails, glands and nerves, make up the largest organ and is a part of the integumentary system. The definition of “Integumentary” means a body’s outer covering.
The largest organ in the human body accounts for approximately 16% of the total body weight and covers a surface area of 22 sq. feet (approximately) which is around 25m2.
The surface area of the skin is often miscalculated. The surface is not flat and the presence of over 5 million appendages like hair follicles and sweat glands increases the epithelial surface area which is specially accessible to microbes.
The thickness and texture is also different on different parts of the body. It is thick on the palms of the hands and the soles of the feet but is comparatively thinner underneath the eyes.
The organ is made up of water, proteins, fats & minerals and the nerves present in the skin assists in feeling sensations of hot and cold.
How does the skin regulate the body’s temperature?
The blood vessels in the dermis constrict when the body is exposed to a cold temperature. This lets the warm blood bypass the skin. It, therefore, attains the same temperature to that it is exposed to. The heat of the body is conserved as the vessels are not diverting warmth to the skin, any further.
What Are The Layers Of The Skin?
There are three layers of tissue that makes it up:
1: The Epidermis (The top layer)
2: The Dermis (The layer in the middle)
3: The Hypodermis (the fatty layer or the layer at the bottom)
Skin Layer #1: The Epidermis
What does the topmost layer do?
The epidermis is the topmost layer that can been seen and touched. There is a protein inside the skin cells, known as keratin, that makes up the skin cells, which sticks with other proteins and forms this layer, altogether.
There are 3 types of cells, present here at the epidermis,
Squamous cells: The external layer is always shed out, which is also called the stratum corneum.
Basal cells: These cells are present right under the squamous cells, near the base of the epidermis.
Melanocytes: These are found at the base of the epidermis and have been found to produce melanin. Melanin gives the skin its colour.
One can also segregate the epidermis into certain layers or strata:
a) Stratum Corneum
Being the outermost layer of the epidermis, the Stratum Corneum is exposed to the atmosphere. This layer plays a protective role majorly and helps to prevent viruses and bacteria from getting into the deep layers. By the process of desquamation, the entire outer layer is replaced with newer cells. New cells move up from the basale layer, pushing the older cells to the surface. This entire process takes about 4 weeks.
b) Stratum Lucidum
The cells in this layer look lucid and clear, which is why it is named as such. This layer is found only in the thicker parts especially on the palms of the hands and fingers and even on the soles of the feet.
c) Stratum Granulosum
This layer is full of granules, which are produced by the keratinocytes. The compound that imparts strength, known as keratin, is there in tiny keratohyalin granules. The keratinocytes produce lipids and NMF that makes the skin waterproof and helps to retain moisture.
[Keratinocytes: The cells that produce keratin
NMF: Natural Moisturising Factor]
d) Stratum Spinosum
As suggested by the name, the Stratum Spinosum possesses spiny protrusions which tightly holds the cells together and prevents the skin from blistering or tearing up.
e) Stratum Basale
This is the deepest layer and is where stem cells are located. The topical products that you apply to the surface do not have any effect here as it fails to reach so deep below, which is why applying stem cells to the skin’s surface is a waste of time. This is also the layer where keratinocytes are born. These keratinocytes reach the outer layer through the process of keratinization. This entire process takes about 26 to 40 days, depending on age, hydration, and genetics.
There are several functions of the epidermis.
The epidermis acts as a protective barrier and keeps the germs and bacteria away from entering the body and causing infections. It also protects against the rain, sun and other such external elements.
New keratin cells are always under production by the epidermis. These cells replace the old dead skin cells that are shed by the body every day (approximately 40,000). Your body basically has a new skin after every 30 days.
The epidermis contains Langerhans cells that are a part of the body’s immune system. The help in fighting off infections and harmful microbes.
Melanin, which is the pigment that imparts the skin its colour is present in the epidermis. The amount of melanin determines the colour and hair, and even the eyes. People with more melanin content have darker skin and tan more quickly under the sun.
Skin Layer #2: The Dermis
The thickest part is the dermis which makes up almost 90% of it.
The dermis is attached to the epidermis with the help of a basement membrane and is divided into two significant areas:
a) Papillary Region:
This region is named after the finger-like projections it possesses, also known as papillae, which extend towards the epidermis. These projections create a bump-like surface that fits like a piece of Lego with the epidermis which in turn strengthens the connection between two successive layers of the skin.
b) Reticular Region:
This region is quite deep into the papillary region and is comparatively thicker. The layer is called such, owing to the dense concentration of collagenous, elastic, and reticular fibers that pass through it. These fibrous proteins impart strength and elasticity to the dermis. It is here, where the roots of hair, sweat & sebaceous glands, blood vessels, receptors, and nails are present.
The collagen and elastin fibers are present here at the dermis. Collagen is a protein that makes skin cells resilient and sturdy. Elastin helps to keep the skin flexible and regain its former shape after being stretched.
The dermis is also the location to which the roots of hair follicles are attached to. The presence of nerves in the dermis helps to feel sensations of pain, and irritation and assists in gauging temperatures.
The skin feels soft and smooth with the help of oil glands present in the dermis. The presence of oil inhibits the skin from absorbing more water than is required.
Glands in the dermis release sweat through the pores which eventually helps to regulate the temperature of the body.
The layers are also kept healthy due to blood vessels, which provide a constant flow of nutrients to the epidermis.
Skin Layer #3: The Hypodermis
The fatty layer at the bottom is also known as the hypordermis.
The hypodermis fat prevents injury to the muscles and bones when you encounter an accident. It also helps in regulating the temperature of the body but preventing us from feeling the extremities of temperatures. The connective tissues present here helps to link up the layers of skin to the bones and muscles.
The nerves and blood vessels get enlarged, here in the hypodermis, and branch out to connect this layer to the rest of the body.
There are approximately 19 million cells and over 60,000 melanocytes in just an inch of our skin. It also shelters more than 1,000 nerve endings and 20 blood vessels.
In Conclusion
The skin is the best shield that you can have against germs and external elements. It helps to keep the body at an optimum temperature and the nerves underneath it provides the sensation of touch.
Therefore, it is important to understand the science behind the its functionality. You need to know how the skin works and implement ways to take care of it properly.