Although the shining star of the integumentary system is the skin, this system encompasses so much more than that. Hair, nails, sensory nerves, and glands all play a part in making up this protective and regulatory system. The integumentary system has a few roles, and each part contributes, works together, and works with other parts of the body to keep us healthy, safe, and balanced.
A quick, close-up look at the picture to the left shows just how intricate the integumentary system is. Here you can see the layers of skin, hairs, follicles, glands, and nerves all working together to create the surface of your body. It's quite amazing really.
This system works to protect your body from foreign substances such as bacteria and harmful environmental hazards such as UV light. It retains bodily moisture, regulates our temperature, provides fuel storage (in the form of fat), cushions and protects the body, eliminates waste materials from the body, and so much more! Here we'll delve into each specialized part of the integumentary system and what function it serves.
We'll start with the star of the show... the skin. The skin is the main component of the integumentary system, and the largest, heaviest organ in the human body. The skin serves several important functions for the body. First and foremost, it acts as a protective barrier against foreign substances, bacteria, and harmful environmental factors. It is the barrier between the outside world and your delicate inner body.
There are three layers of skin. The outermost layer is the epidermis, and it is the tougher, more protective layer. Under that lies the dermis, where most of the structures associated with the skin (such as nerves and hair follicles) are housed. The innermost layer is called the subcutaneous layer and it is a layer of fat and connective tissue which stores energy for the body. It also cushions and insulates the body and provides structure for the skin to connect to underlying muscles.
The skin interacts and assists other body systems such as the immune system. It is the body's frontline in defense against infections and injuries. It provides Vitamin D from the sun, which is crucial for the body's absorption of calcium. This aids many other systems in the body.
Next up is hair- your hair is all a part of your integumentary system, from the hair on
your head to the hairs inside your nose and ears. Hair is made up of keratin that forms thin threads of proteins. It covers all parts of the body except for the palms of the hands and soles of the feet, which have thicker, tougher skin than the rest of the body. Hair serves many important functions. It helps with regulating the body's temperature, most of the time by keeping us warm and insulated. It also gives us protection. Hair that covers the body protects us against UV radiation by covering the skin. Hairs inside the ears and nose help block out foreign matter, protecting the respiratory system. Lastly, hair contains nerve endings which allow us to sense what is around us. Each hair follicle is surrounded by a nerve fiber called a hair receptor. When the hair is moved by something in its external environment, this nerve sends information to the brain, and we can sense and react to that stimulus. These nerves are sensory nerves, which are part of the integumentary system but work directly with the nervous system to keep us safe and processing information.
Nails are another part of the integumentary system which protect us. Also made from keratin, they provide a nice, hard covering for our fingertips and toes. They also help us with sensing, touch, and fine motor skills.
Glands which lie in and below the skin are the final part of the integumentary system. There are four different types:
Sweat glands-
Eccrine Sweat glands produce clear, odorless sweat throughout the body. These sweat glands mainly help to cool the body and prevent overheating.
Apocrine Sweat glands are larger and located in areas of the body where the lymphatic system drains such as the armpits and groin. These glands produce odorous sweat and help to detoxify the body.
Ciliary glands are modified glands that are inside the eyes which help keep the eye lubricated.
Sebaceous glands-
These glands produce and oily substance called sebum which help protect and
moisturize the skin and hair follicles.
Ceruminous glands-
These are located inside the ear and produce ear wax, which helps keep foreign
materials out of the ear.
Mammary glands-
These glands are located in the chest, one on each side of the body. Both males
and females have mammary glands. In females they produce milk for nourishing
babies.
This expansive system of interworking parts- skin, hair, nerves, nails, and glands- all make up the integumentary system. It is the living tissue that serves as the first line of defense for our bodies and helps us sense the world around us. It also helps the world around us sense us. When we identify someone by their physical appearance, much of what we use to do that is the integumentary system. Their skin tone, their hair color- these are factors that make each individual unique, beautiful, and identifiable. So, this system is so much more than just a covering for our bodies. It is part of our physical identity in this life.