Our Body's Largest Organ: The Skin

By Hadia Arian

Introduction

If you look closely, the skin tells a story. Every freckle, crease, scar, and birthmark is a mark on a living map carried by the integumentary system, the body’s outermost protective network. This system doesn’t just wrap us up; it shields us, cools us, senses the world for us, and constantly renews itself. As the largest organ in the body, the skin serves as a physical barrier protecting our body.

The Secrets of the Skin

Your skin is the largest and heaviest organ you have. It can weigh almost 3 or more kilograms and is about 2 millimetres thick on average. However, that thickness varies — it’s much thinner on sensitive areas like the eyelids and much thicker on high-pressure areas such as the soles of your feet. In just one square inch, your skin contains close to 19 million cells.

Functions of the Skin

• Hold in fluid and prevent dehydration.

• Help you feel sensations, like temperature or pain.

• Keep out bacteria, viruses and other causes of infection.

• Stabilise your body temperature.

• Synthesise vitamin D in response to sun exposure.

The Three Layers of the Skin

Your skin is composed of three layers, with nerves that recognise different sensations in each layer:

• Epidermis: The top layer of your skin. This is the part of your skin that you can see and touch. It’s made up of three types of cells: melanocytes, keratinocytes and Langerhans. It gives your skin its colour and provides a waterproof barrier.

• Dermis: The middle layer of your skin. This layer is the thickest. It contains sweat and oil glands and hair follicles.

• Hypodermis: The bottom layer of your skin. It’s the fatty layer of your skin that helps insulate your body.

What are the functions of the epidermis?

Each layer of your skin works together to keep your body safe, including your skeletal system, organs, muscles and tissues. The epidermis has many additional functions, including:

• Hydration. The outermost layer of the epidermis (stratum corneum) holds in water and keeps your skin hydrated and healthy.

• Producing new skin cells. New skin cells develop at the bottom layer of your epidermis (stratum Basale) and travel up through the other layers as they get older. They reach the outermost layer of your epidermis after about a month, where the skin cells shed from your body as new cells develop at the bottom layer.

• Protection. The epidermis acts like armour to protect your body from harm, including ultraviolet (UV) radiation, pathogens (bacteria, viruses, fungi and parasites) and chemicals.

• Skin colour. The epidermis has cells called melanocytes which make melanin, which is a group of pigments in your skin that provides skin colour.

Diseases of the Skin

• Acne - blocked skin follicles that lead to oil, bacteria and dead skin buildup in your pores.

• Alopecia areata - losing your hair in small patches.

• Atopic dermatitis (eczema) - dry, itchy skin that leads to swelling, cracking or scaliness.

• Psoriasis - scaly skin that may swell or feel hot.

• Raynaud’s phenomenon, periodic reduced blood flow to your fingers, toes or other body parts, causing numbness or skin colour change.

• Rosacea, flushed, thick skin and pimples, usually on the face.

• Skin cancer - uncontrolled growth of abnormal skin cells.

• Vitiligo - patches of skin that lose pigment.

Some rarer skin diseases that might interest you could include:

• Argyri - changes in skin colour due to silver buildup in your body.

• Chromhidrosis - coloured sweat.

• Epidermolysis bullosa - a connective tissue disorder that causes fragile skin that blisters and tears easily.

• Harlequin ichthyosis - thick, hard patches or plates on the skin that are present at birth.

But what actually causes these types of diseases?

• Bacteria trapped in your pores or hair follicles.

• Conditions that affect your thyroid, kidneys or immune system.

• Contact with environmental triggers, such as allergens or another person’s skin.

• Genetics

• Fungus or parasites living on your skin.

• Medications, such as the ones that treat inflammatory bowel disease (IBD).

• Viruses.

• Diabetes.

• Sun.

How are Skin Diseases Diagnosed?

• Skin patch test - applying small amounts of substances to test for allergic reactions.

• Black light examination (Wood light test) - using an ultraviolet (UV) light to view your skin’s pigment more clearly.

• Diascopy - pressing a microscope slide against a skin patch to see if the skin changes colour.

• Dermoscopy - using a hand-held device called a dermatoscope to diagnose skin lesions.

• Tzanck test - examining the fluid from a blister to check for herpes simplex or herpes zoster.

How Are Skin Diseases Treated?

-              Antibiotics

-              Antihistamines

-              Laser skin resurfacing

-              Creams, ointments and gels

-              Oral medications

How can we prevent Skin Diseases?

-              Avoid sharing personal items or cosmetics

-              Disinfect objects that you take outside like the gym

-              Drink lots of water

-              A healthy and well-balanced diet

-              Sleep well

-              Sun cream

-              Wash hands regularly and thoroughly

Sources and a good place to find more information and read about anything you found interesting:chat

https://my.clevelandclinic.org/