Understanding Integumentary System Terminology

1. Introduction to the Integumentary System

What do you think when you look at your skin in the mirror? Do you think about covering it with makeup, adding a tattoo, or maybe a body piercing? Or do you think about the fact that the skin belongs to one of the body’s most essential and dynamic systems: the integumentary system? The integumentary system refers to the skin and its accessory structures (such as hair, nails, glands, and sensory receptors).

In the adult human body, the skin makes up about 16 percent of body weight and covers an area of 1.5 to 2 m². In fact, the skin and accessory structures are the largest organ system in the human body. As such, the skin protects your inner organs, and it is in need of daily care and protection to maintain its health.

Functions of the integumentary system include:

• Protection – It acts as a barrier against pathogens and environmental damage. Your skin provides excellent protection against pathogens that could make you sick.
• Temperature regulation – It maintains homeostasis (relatively constant internal body conditions), helping you to maintain a relatively constant temperature. When you’re hot, you sweat and your blood vessels dilate (meaning that they widen in diameter, which is why you may look flushed). When you’re cold, your blood vessels constrict, getting smaller in diameter to conserve heat.
• Sensation – It contains nerve endings that detect sensations such as touch, pressure, pain, and temperature.
• Excretion – It eliminates waste through sweat.
• Synthesis of vitamin D – The skin converts sunlight into active vitamin D.

2. Common Word Parts

Now that you have started thinking about the skin, let’s begin to review some basic skin-related terms.

The table below shows some important prefixes commonly associated with the skin and skin conditions.

In the examples above, you may recognize some roots that you have studied previously. The table below shows these review terms and some new terms.

Finally, let’s examine some suffixes related to integumentary conditions. You should recognize these as you have seen them before.

2a. Word Parts Related to Hair

You have learned that the combining form trich/o refers to hair. Another combining form, pil/o, also refers to hair.

Hair grows from a hair follicle embedded in the skin. The visible part of hair is called the hair shaft, which grows from the deeper hair root.

Common hair conditions include:

Alopecia – Hair loss.
Hirsutism – Excess hair growth.
Trichomycosis – Fungal infection of hair follicles.

Click through the images below to see hairs of a patient with trichomycosis, the head of a person with alopecia, and the face of a person with hirsutism.

2b. Word Parts Related to Nails

As mentioned earlier, nails contain the protein keratin. Claws, like cat claws, have the same protein that is also in horns (antlers are bone under a covering).

The skin under the nail itself is called the nail bed. If you look at your nail, you can see a white crescent at its base called the lunula. Finally, there is protective tissue at the nail base called the cuticle.

The image below shows the important nail structures described above: the nail bed, the lunula, and the cuticle.

Nail conditions include:

Onychomycosis – A fungal infection of the nail.
Paronychia – An infection around the nail.
Koilonychia – Spoon-shaped nails due to iron deficiency (koil/o is a word root that means having a hollow or concave shape).

2c. Word Parts Related to Glands

The combining form for the word gland itself is aden/o. There are two major types of skin glands in humans. You already learned about sebaceous glands that produce oily sebum. Sebaceous glands are typically found associated with hair follicles. The other major category is the sweat glands, which produce sweat and are formally known as sudoriferous glands.

Medical conditions associated with these glands include:

Acne vulgaris (acne) – A condition caused by clogged sebaceous glands that cause inflammation.
Hyperhidrosis – Excessive sweating.
Anhidrosis – Lack of sweating.

The figure below provides more information about acne. Acne is a skin condition that typically occurs on areas of the skin that are rich in sebaceous glands (face and back). It is most common along with the onset of puberty due to associated hormonal changes, but can also occur in infants and continue into adulthood. Hormones, such as androgens, stimulate the release of sebum. An overproduction and accumulation of sebum along with keratin can block hair follicles. The structure caused by this blockage is called a comedo. This plug is initially white. The sebum, when oxidized by exposure to air, turns black. Acne results from infection by acne-causing bacteria (Propionibacterium and Staphylococcus), which can lead to redness and potential scarring due to the natural wound healing process.

You are probably familiar with informal terms such as whitehead and blackhead. The illustration below shows the same process as in the figure above, but using this familiar terminology.

2d. Common Diseases and Disorders

There are a variety of types of skin conditions, including inflammatory conditions, skin infections, and cancers. Only a few examples are presented here. You will learn about more conditions in the lesson Common Integumentary System Disorders.

Inflammatory conditions include:

Dermatitis – Skin inflammation.
Psoriasis – An autoimmune skin disorder that causes scaling or plaques, as well as other symptoms.
Eczema – An allergic reaction that produces dry, itchy patches of skin that resemble rashes (shown below).

Infections include:

Impetigo – A common bacterial skin infection (shown below on the left).
Tinea – A fungal skin infection; specific types of tineas affect the body (ringworm is shown below on the right), feet (athlete’s foot), or groin and nearby tissues (jock itch).

Cancers include:

Basal cell carcinoma (BCC) – The most common skin cancer; affects dividing cells deep in the epidermis. See the left image below.
Squamous cell carcinoma (SCC) – The second most common skin cancer; affects keratinocytes.
Melanoma – A type of malignant skin cancer that develops from melanocytes; deadliest form of skin cancer.

Finally, some conditions refer to specific types of wounds or scars. These include:

Abrasion – superficial skin wound caused by scraping or wearing away.
Laceration – A deep cut or tear in the skin.
Keloid – Excessive scar tissue formation.
Ulcer – An open sore or lesion that fails to heal.

did you know

Dermatillomania, sometimes called excoriation disorder, is a condition in which someone compulsively picks at their skin. This is one of a group of conditions called body focused repetitive behaviors, which also includes nail biting (onycophagia) and hair pulling (trichotillomania) (TLC Foundation, 2025). Dermatotillomania can be severe, leading to significant distress and to substantial skin damage. Although there is a lack of data on treatment approaches, both psychotherapy and medications are used (Lochner et al., 2017).

The image below shows damage caused by skin-picking.

2e. Diagnostic and Treatment Terms

There are many terms used for diagnosis and treatment in dermatology. A very common term is biopsy, which refers to a tissue sample that is removed for testing. You may have heard of someone having a cancer biopsy, for example. Sometimes, lesions (areas of damaged or diseased tissue) can be removed using cryotherapy, which freezes the tissue. Some skin cancers can be treated this way.

A patch test is one of several types of skin tests used to test for allergies. In some tests, small amounts of allergens are placed under the skin to monitor any reactions. In patch testing, as shown in the figure below, patches containing allergens are placed on the skin and left in place for 48 hours to determine whether there is a reaction (Cleveland Clinic, 2025).

The image below shows a patch test.

A Wood’s lamp is a device that shines ultraviolet light to detect fungal infections such as ringworm, among other conditions.

Sometimes, dead or damaged tissue and foreign matter may need to be removed to allow skin to heal. This is called debridement. For example, someone with an infected ulcer that contains dead tissue may need to have the wound debrided.

Finally, Mohs surgery is a specialized treatment for skin cancer that is used for delicate cases to spare as much tissue as possible. This technique involves removing tissue, then checking under a microscope to see if the full cancer has been removed with clean margins (healthy cells around the cancer, suggesting that the entire cancer has been removed). If the margins are not clear, then the surgeon can return immediately to the waiting patient to remove more tissue. This helps the surgeon remove precisely the right amount of tissue and not more, which is especially important for facial lesions.

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terms to know

The table below lists terms that are especially important or that may be difficult to pronounce. Audio is provided to help you learn how to say these terms.

REFERENCES

Lochner, C., Roos, A., & Stein, D. J. (2017). Excoriation (skin-picking) disorder: a systematic review of treatment options. Neuropsychiatric disease and treatment, 13, 1867–1872. doi.org/10.2147/NDT.S121138

The TLC Foundation for Body-Focused Repetitive Disorders. (2025). What is a BFRB? Body-Focused Repetitive Behavior | BFRB | BFRB Awareness . https://www.bfrb.org/what-are-bfrbs.

Cleveland Clinic. (2025, April 21). Patch Test. Patch Testing for Skin Allergies: Procedure & Results . https://my.clevelandclinic.org .