The physiology of the human body is fascinating—but what about the human skin? It’s the largest organ of our body and makes up part of the integumentary system. It also has more depth than meets the eye, with several layers and functions. The skin is also one of the best indicators of our general health. If someone is sick, it often shows up in their skin first and can be a telltale sign.
Whether you’re in a healthcare profession, studying a Master’s in Nursing, or even working in a field like tattooing—it’s critical to understand the anatomy of skin. It performs many vital functions, one of the most important being the first line of defence against bacteria and other organisms. Our quick guide to the physiology of human skin will teach you everything you need to know about the different layers, from the epidermis to the subcutaneous layer, as well as the different glands and blood vessels.
What does the skin do?
The skin has many functions, which include protecting the body, acting as a sensory organ, increasing mobility, and even temperature regulation.
The different layers of skin
The skin is divided into three layers, each one with its own function and job. These three layers are the epidermis, dermis, and subcutaneous layers. The thickness of these layers can also change from person to person.
The epidermis
The epidermis is the outer layer of skin. It’s the layer that you will see or feel when you touch or look at another person or yourself. It consists of three major cells: keratinocytes, melanocytes, and Langerhans cells.
The thickness of the epidermis will vary from person to person, as well as throughout your body. For example, the soles of your feet and palms of your hand will have much thicker skin than your face or eyelids. For comparison, the average palm can be as thick as 1.5 millimetres, while the eyelids are as thick as 0.05 millimetres.
The colour of your epidermis will depend on your melanocyte cells and the amount of melanin it makes. There are two types of melanin, which will also determine how much pigment you have—eumelanin and pheomelanin.
Eumelanin is the type of melanin associated with the dark colours in your hair, skin, and eyes. Pheomelanin is the type that primarily makes up any of the pink and red colours in your body, for example, on your lips and nipples.
The dermis
The dermis is the middle layer of skin, in between the epidermis and subcutaneous layer. Where the epidermis is responsible for hydrating your body and producing new skin cells—the dermis contains all your connective tissue, nerve endings, sweat glands, and hair follicles.
Within the dermis, there are two more layers, the reticular dermis and the papillary dermis. The reticular dermis is the layer that contains the blood vessels, nerves, fat cells, glands, and hair follicles. The papillary dermis is much thinner than the reticular layer, but consists of nerve fibres, touch receptors, cells that fight bacteria, and fibroblast cells, and also contains fat cells and blood vessels.
The subcutaneous layer
The subcutaneous layer, also known as the hypodermis or superficial fascia, is the bottom layer of skin. It is the layer of skin that connects your dermis layer to your muscles and bones. The subcutaneous layer is also responsible for producing fat cells, known as adipocytes, which store energy.
This layer also provides insulation to your body, protecting you from the cold, and also produces sweat to regulate your temperature. Along with this, the subcutaneous layer also protects your body and acts as a shock absorber to protect your organs, muscles, and bones.
Hair, nails, and the skin
If you’re wondering where your hair and nails come from—it all starts in the skin. Your hair and nails are created by cells located in the epidermis. The keratinocytes in your epidermis produce a type of protein known as keratin, which is a basic component in your hair and nails.
At the bottom of your hair follicle, the papilla, cells multiply and create keratin. This keratin structure is then pushed through the follicle and comes out as a shaft of hair. Nails are formed by a similar process, where dead cells accumulate due to keratin and push the nail forward.
Taking care of your skin
The skin is one of the most versatile organs in our body, and it’s critical to have basic knowledge of how to take care of it properly. Common problems include:
- Acne
- Dermatitis
- Skin cancer
- Sunburn
A few of the best ways to take care of your skin include protecting yourself from the sun, reducing stress, staying away from smoking, and eating a healthy diet. If you do have any concerns about your skin, it’s best to contact your doctor or dermatologist.
