LARGEST ORGAN OF THE BODY:

Body organs aren't all internal like the brain or the heart. There is one we wear on the outside. Skin is our largest organ—adults carry around 8 pounds (3.6 kilograms). It covers about 22 square feet (2 square meters) of it. This fleshy covering does a lot more than make us look presentable. In fact, without it, we'd literally evaporate.  

IMPORTANT FUNCTIONS OF SKIN:

Skin acts as a waterproof, insulating shield, guarding the body against extremes of temperature, damaging sunlight, and harmful chemicals. It also exudes antibacterial substances that prevent infection and manufactures vitamin D for converting calcium into healthy bones. Skin additionally is a huge sensor packed with nerves for keeping the brain in touch with the outside world. At the same time, skin allows us free movement, proving itself an amazingly versatile organ.

SKIN PROTECTION TO THE BODY:

Skin is made up of three layers. The outermost is the epidermis. This consists mainly of cells called keratinocytes, made from the tough protein keratin. The epidermis harbors defensive Langerhans cells, which alert the body's immune system to viruses and other infectious agents.The epidermis is bonded to a deeper skin layer below known as the dermis, which gives the organ its strength and elasticity thanks to fibers of collagen and elastin.

       

The biggest external organ of the body is undoubtedly the skin. Our body is covered from head to toe with skin covering roughly 20 square meters. 

The skin acts as a defence mechanism to fight against foreign bodies and substances. They are the frontline workers of our body. They are strong and rigid hence, do not damage easily. But, when they do get damaged, they heal by themselves, forming scar tissue and discolouration or getting depigmented.

It also functions in temperature regulation, insulation, protecting from bacteria, viruses and microbes and sensation-to sense touch, hot and cold.

The skin has three layers:

The outer layer epidermis acts as a barrier for foreign bodies and creates our skin tone.

The middle layer is the dermis which contains tough connective tissues, hair follicles and sweat glands.

The last layer of the skin is the subcutaneous tissue; hypodermis that's made of fat and connective tissue.

The thickness of the skin varies from location to location. For instance, the skin around the eyes and the eyelids are the thinnest of about 0.5mm thick hence, they seem to age early by showing signs of aging like wrinkles. On the contrary, the skin on the palms and the soles of the feet are the thickest on the body with 4mm thickness hence, these parts are tough and thick and show aging signs quite late.

    

The answer to this question probably isn't what you are expecting, an actual organ organ. Whereas, in reality it is something we don't exactly list in the category of organs, the skin. Your skin is the largest external organ that is present in your body.  

It is unarguably the largest organ of the body because it covers the entirety of us and alone constitutes for about 16% of your body's overall mass. So, you can never lose this sixteen percent no matter what happens! On top of that, your skin is also 2 complete millimetre thick.  

Plus, I really think we undermine the importance and strength of the skin in comparison to other organs. Even though it works all day and all night to keep you well on your feet. Had it not been for the sake, all of us would be an unconfined mess, quite literally.  

What are the functions of skin? 

• provide protection against harmful particles present in the outer environment      
• reduces harmful effects of UV radiations     
• acts as a sensory organ (helps you feel pain and touch)   
• regulate overall body temperature  
• stores water, fats and vitamin D.  

Having put this out there, in light of the recent researches, your skin may no longer be the largest organ of your body. Lets wait and see!