Integumentary System

What is the integumentary system?

Your integumentary system is your body’s outer layer. It’s made up of your skin, nails, hair and the glands and nerves on your skin. Your integumentary system acts as a physical barrier — protecting your body from bacteria, infection, injury and sunlight. It also helps regulate your body temperature and allows you to feel skin sensations like hot and cold.

What makes up the integumentary system?

Your integumentary system is an organ that consists of a few main structures: skin, nails, hair and glands, along with the nerves and blood vessels that support them.

Skin

Your skin is the largest and heaviest organ in your body. It weighs about six pounds (or more) and is approximately 2 millimeters thick — thinner on sensitive areas like eyelids, and thicker on surfaces that take more stress, like the soles of your feet. One inch of your skin contains nearly 19 million cells.

Your skin is composed of three layers, with nerves that recognize 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 color 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.

Nails

Your nails protect the ends of your fingers and toes. The anatomy of your nail consists of:

• Nail plate: The hard part of your nail you can see.
• Nail bed: The skin under your nail plate.
• Cuticle: The thin skin at the base of your nail plate.
• Matrix: The “root” of your nail responsible for making it grow.
• Lunula: The white, moon-shaped part of your nail plate.

Hair

Our hair does more than help us look nice. The hair on your head helps keep heat in your body. Your eyelashes and eyebrows help protect your eyes from dirt and water.

Your hair is made of a protein called keratin. Your hair consists of three parts: the shaft, follicle and bulb.

• Hair shaft: The part of your hair you can see, touch and style.
• Hair follicle: The tube-like structure that keeps your hair in your skin.
• Hair bulb: Located under your skin and responsible for hair growth.

Goosebumps are caused by your integumentary system. We all have hair erector muscles connected to our hair follicles and skin. When it contracts, it makes your hair stand up. The “goosebumps” are what we see when these tiny muscles contract.

Glands

Glands are found throughout your skin. They release materials like water, salt or oil from under your skin to the surface of your skin. Your integumentary system consists of the following glands:

• Sudoriferous glands: These are the glands that secrete sweat through your skin. There are two types of sweat glands: eccrine glands and apocrine glands. Eccrine glands are all over your body and open to your pores, while apocrine glands open into your hair follicles.
• Sebaceous glands: These glands produce sebum (oil) and give your face its oil.
• Ceruminous glands: These are the glands in your ear that secrete ear wax.
• Mammary glands: These are the glands on a person’s chest. In people assigned female at birth (AFAB), mammary glands produce milk after giving birth.

What is the purpose of the integumentary system?

Your integumentary system protects your body from infection and injuries you could get from your external environment. It’s your body’s coat of armor and the first line of defense against viruses, bacteria and other microbes. It shields your body from harmful light and helps regulate your body temperature. Your integumentary system stores fat, water, glucose and vitamin D, and helps support your immune system to protect you from diseases.

Your integumentary system has many important functions. It:

• Provides physical protection against bacteria and germs.
• Absorbs and helps heal abrasions, cuts and other injuries.
• Cushions and protects your body from infection.
• Protects you from the sun’s ultraviolet (UV) rays and sunburn.
• Excretes sebum, sweat and other waste from your body.
• Regulates your body temperature and allows you to stay cool.
• Helps you feel heat, cold and detect other sensations.
• Synthesizes vitamin D.

How does the integumentary system work with other systems?

Your body is like a complex machine. All of your organs, body parts and systems work together to keep everything in check and working as it should. Your integumentary system plays a role in helping other systems maintain their functions.

For example, it helps your immune system because it’s the first line of defense against bacteria and infection. It also sends white blood cells to injuries to begin the healing process.

Your integumentary system helps you absorb vitamin D, which acts as a hormone and is crucial to your bone health because it affects calcium absorption.

The tiny hairs in your nose help your respiratory system because they filter out dust and other particles before you inhale them into your lungs.

What are common conditions or disorders of the integumentary system?

Your integumentary system is unique because most health conditions associated with it are visible. Unlike your internal organs, health conditions of your skin, hair and nails are typically external — meaning you and your healthcare provider can see them.

Skin disorders

Some of the most common skin disorders are:

• Allergies like contact dermatitis and poison ivy rashes.
• Blisters from trauma.
• Bug bites, such as spider bites, tick bites and mosquito bites.
• Skin cancer, including melanoma.
• Skin infections like cellulitis.
• Skin rashes and dry skin.
• Skin disorders like acne, eczema, psoriasis and vitiligo.
• Skin lesions like moles, freckles and skin tags.
• Wounds, burns (including sunburns) and scars.

Hair disorders

Hair loss is the most common condition that affects your hair. Some types of hair loss are temporary, while others are permanent. The most common types of hair loss include:

• Alopecia areata: Patches of hair loss caused by an autoimmune disease.
• Androgenic alopecia: Baldness in both genders/sexes that’s based on genetics.
• Anagen effluvium: Loss of hair during its growth phase; this often occurs during medical treatments like chemotherapy.
• Telogen effluvium: Loss of hair during its rest phase. It typically shows up a few months after your body goes through something stressful or from hormonal changes.
• Traumatic alopecia: Hair loss due to damage to your scalp from hair styling, through rubbing your scalp repeatedly against a surface or hat or by playing with and breaking your hair.

Other common conditions of hair that aren’t related to hair loss are:

• Dandruff: It causes white or yellow flakes on your scalp and hair shaft. It’s also known as seborrheic dermatitis.
• Head lice: Tiny, crawling insects that live in a person’s head hair.
• Hirsutism: Excessive hair growth in people assigned female at birth.

Nail disorders

Like the other structures of your integumentary system, your nails are always exposed. Nail issues can be caused by your shoes, poor hygiene or from using nail files or trimmers incorrectly. Some of the more common nail conditions are:

• Onychomycosis: Nail fungus in your fingernails or toenails.
• Onycholysis: When your nail separates from your nail bed.
• Psoriasis of the nails: A skin condition that causes pitting, nail discoloration and other symptoms.
• Lichen planus: A rash that appears as ridges or grooves on your nail.
• Paronychia: An inflammation or infection of the tissue directly surrounding your nail.

Gland disorders

Some conditions of the sweat and sebaceous glands are:

• Hyperhidrosis: Excessive sweating.
• Seborrheic dermatitis: Scaly, red patches that affect your face, chest or back. When it’s on your head, it’s called dandruff.
• Sebaceous hyperplasia: A skin condition common in people who are older that causes small, yellowish bumps on your skin.

A note from Cleveland Clinic

Your integumentary system is your body’s first line of defense against bacteria, injury and outside elements like sunshine and rain. Your skin, and its structures all play an important role in maintaining balance with other systems in your body. Like other organs, you can have problems with your integumentary system like acne, hair loss or nail fungus. Your healthcare provider can help you keep your skin, hair and nails healthy.