What does the term "integument" mean in biology?

In biology, the term "integument" refers to the outer covering of an organism, serving as a protective barrier that separates it from the external environment. It protects against foreign matter while facilitating communication with the surroundings, enabling the organism to thrive in its specific habitat. The integument varies across different organisms. In unicellular organisms, it comprises the cell membrane and any secreted coating. Invertebrates typically have a layer of epithelial cells, often with secreted coatings. Among vertebrates, the integument is a complex organ system with structures like scales, feathers, and hair. The skin is the largest and most versatile organ of the animal body.

What is the main purpose of the integument in living organisms?

The integument is a network of features forming the covering of an organism. It separates the organism's body from the environment, protecting it from foreign matter while enabling communication with the outside, allowing it to live in a particular environment. The integument varies across organisms. It can be a single-cell layer in unicellular organisms or multiple cell layers in invertebrates and vertebrates. It often includes a noncellular coating or cuticle secreted by the epidermis, though vertebrate skin lacks these coatings but has glands and horny structures. Human skin, a type of integument, consists of the epidermis , dermis, and subcutis, providing protection and sensory stimuli.

What are some examples of integument in animals and plants?

The integument is a covering that separates an organism from its environment, protecting it from foreign matter while enabling communication with the outside. Examples of integument in animals: * Vertebrates The integumentary system can include scales, feathers, and hair. For instance, reptiles' thick stratum corneum prevents water loss, while birds use feathers for flight and insulation. Mammals possess hair and other horny derivatives like nails and horns. * Invertebrates The integument consists of a layer of epithelial cells, often with secreted coatings. Examples of integument in plants: * Dermal Tissue The epidermis, the outer protective layer, regulates the exchange of water, carbon dioxide, and oxygen. Features like cutin, waxes, and trichomes minimize water loss and protect against environmental stressors. * Tree Bark Bark protects stems from water loss, insects, and fire. The outer bark, made of dead tissue, is shed as the tree grows, while the inner bark consists of living tissues.

How does the integument protect the body from the environment?

The integument, a term for the covering of an organism, protects the body by separating it from the environment and enabling communication with it. In vertebrates, the integumentary system has evolved into a complex organ system with multiple layers. The skin serves as a physical barrier against infection and shields against injury, foreign matter, disease organisms, and harmful rays from the sun. The skin also regulates internal body temperature and embodies the sense of touch. The skin's effectiveness as a barrier is not absolute; noxious substances can still gain entry and evoke an immune response.

What are the major layers or parts that make up the integument in humans?

The integument in humans, also known as the skin, is the body's covering that provides protection and receives sensory stimuli from the external environment. It consists of three layers of tissue: * The epidermis, the outermost layer, contains the primary protective structure, the stratum corneum. * The dermis is a fibrous layer that supports and strengthens the epidermis. Nerves that extend through the dermis are sensitive to heat, cold, pain, and pressure. Sweat and oil glands lie in the deeper stratum reticulare, as do the bases of hair follicles, the nail beds, and blood and lymph vessels. * The subcutis, or hypodermis, is a subcutaneous layer of fat beneath the dermis that supplies nutrients to the other two layers and cushions and insulates the body.

How does the integument help regulate temperature and prevent disease in organisms?

The integument, a network of features forming an organism's covering, serves as a protective barrier and a means of communication with the environment. In vertebrates, the skin regulates internal body temperature through insulation and control of blood flow. The skin's uppermost layers are dead, shielding against injury, foreign matter, disease organisms, and harmful rays. Nerve endings in the dermis report conditions, prompting adjustments. The skin prevents many disease-causing germs from entering the body, unless there is an opening. Glands secrete substances like fatty acids and lysozyme that kill some bacteria. Langerhans cells recognize and respond to foreign substances, triggering an immune response. Conversely, cold causes vessel contraction and shivering, conserving or generating heat. The skin also hosts microorganisms, establishing a balanced environment that stabilizes the surface and prevents the overgrowth of any single type of microorganism.

Integument

Images & Videos

A pangolin walks through grass with a blue circle around it and the word endangered written in white across the image.

Diagram showing four types of fish scales: ctenoid scales from a bass, cycloid scales from a salmon, ganoid scales from a gar, and placoid scales from a shark, each illustrated with a close-up and the corresponding fish silhouette.

Investigating dogs' remarkable sense of smell

Detailed cross-section illustration of human skin showing layers including the epidermis, dermis, and subcutaneous fat, with labeled structures such as hair, pores, sweat gland, oil gland, nerves, blood vessels, and hair follicle.

At a Glance

integument summary

Integument

biology

Also known as: integumentary system

Written by

F. John G. Ebling

Fact-checked by

Britannica Editors

Last updated

Nov. 6, 2026 •History

Top Questions

What does the term "integument" mean in biology?
In biology, the term "integument" refers to the outer covering of an organism, serving as a protective barrier that separates it from the external environment. It protects against foreign matter while facilitating communication with the surroundings, enabling the organism to thrive in its specific habitat.

The integument varies across different organisms. In unicellular organisms, it comprises the cell membrane and any secreted coating. Invertebrates typically have a layer of epithelial cells, often with secreted coatings. Among vertebrates, the integument is a complex organ system with structures like scales, feathers, and hair. The skin is the largest and most versatile organ of the animal body.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What is the main purpose of the integument in living organisms?
The integument is a network of features forming the covering of an organism. It separates the organism's body from the environment, protecting it from foreign matter while enabling communication with the outside, allowing it to live in a particular environment.

The integument varies across organisms. It can be a single-cell layer in unicellular organisms or multiple cell layers in invertebrates and vertebrates. It often includes a noncellular coating or cuticle secreted by the epidermis, though vertebrate skin lacks these coatings but has glands and horny structures. Human skin, a type of integument, consists of the epidermis, dermis, and subcutis, providing protection and sensory stimuli.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What are some examples of integument in animals and plants?
The integument is a covering that separates an organism from its environment, protecting it from foreign matter while enabling communication with the outside.

Examples of integument in animals:
* Vertebrates The integumentary system can include scales, feathers, and hair. For instance, reptiles' thick stratum corneum prevents water loss, while birds use feathers for flight and insulation. Mammals possess hair and other horny derivatives like nails and horns.
* Invertebrates The integument consists of a layer of epithelial cells, often with secreted coatings.

Examples of integument in plants:
* Dermal Tissue The epidermis, the outer protective layer, regulates the exchange of water, carbon dioxide, and oxygen. Features like cutin, waxes, and trichomes minimize water loss and protect against environmental stressors.
* Tree Bark Bark protects stems from water loss, insects, and fire. The outer bark, made of dead tissue, is shed as the tree grows, while the inner bark consists of living tissues.
3 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How does the integument protect the body from the environment?
The integument, a term for the covering of an organism, protects the body by separating it from the environment and enabling communication with it. In vertebrates, the integumentary system has evolved into a complex organ system with multiple layers.

The skin serves as a physical barrier against infection and shields against injury, foreign matter, disease organisms, and harmful rays from the sun. The skin also regulates internal body temperature and embodies the sense of touch. The skin's effectiveness as a barrier is not absolute; noxious substances can still gain entry and evoke an immune response.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What are the major layers or parts that make up the integument in humans?
The integument in humans, also known as the skin, is the body's covering that provides protection and receives sensory stimuli from the external environment. It consists of three layers of tissue:
* The epidermis, the outermost layer, contains the primary protective structure, the stratum corneum.
* The dermis is a fibrous layer that supports and strengthens the epidermis. Nerves that extend through the dermis are sensitive to heat, cold, pain, and pressure. Sweat and oil glands lie in the deeper stratum reticulare, as do the bases of hair follicles, the nail beds, and blood and lymph vessels.
* The subcutis, or hypodermis, is a subcutaneous layer of fat beneath the dermis that supplies nutrients to the other two layers and cushions and insulates the body.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How does the integument help regulate temperature and prevent disease in organisms?
The integument, a network of features forming an organism's covering, serves as a protective barrier and a means of communication with the environment. In vertebrates, the skin regulates internal body temperature through insulation and control of blood flow.

The skin's uppermost layers are dead, shielding against injury, foreign matter, disease organisms, and harmful rays. Nerve endings in the dermis report conditions, prompting adjustments. The skin prevents many disease-causing germs from entering the body, unless there is an opening. Glands secrete substances like fatty acids and lysozyme that kill some bacteria. Langerhans cells recognize and respond to foreign substances, triggering an immune response.

Conversely, cold causes vessel contraction and shivering, conserving or generating heat. The skin also hosts microorganisms, establishing a balanced environment that stabilizes the surface and prevents the overgrowth of any single type of microorganism.
6 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Integument, in biology, network of features that forms the covering of an organism. The integument delimits the body of the organism, separating it from the environment and protecting it from foreign matter. At the same time it gives communication with the outside, enabling an organism to live in a particular environment.

Among unicellular organisms, such as bacteria and protozoans, the integument corresponds to the cell membrane and any secreted coating that the organism produces. In most invertebrate animals a layer (or layers) of surface (epithelial) cells—often with additional secreted coatings—constitutes the integument. Among the vertebrates the boundary covering—with a variety of derived elements such as scales, feathers, and hair—has assumed the complexity of an organ system, the integumentary system.

The integument is composed of layers that may be of single cell thickness, as in many invertebrates, or multiple cell thickness, as in some invertebrates and all vertebrates. In every case the cells that give rise to the integuments belong to that class of tissue called epithelium, which in most animals is called epidermis. Underlying the epidermis and supplying it with nourishment is the dermis. In addition to the cellular layers, the integument often includes a noncellular coating, or cuticle, that is secreted by the epidermis. Such coatings are found in most invertebrates. The vertebrate skin has generated many kinds of glands and a variety of horny structures, but it lacks coatings.

The wide diversity of integuments among vertebrates further exemplifies the adaptive character of the body covering: from the almost impenetrable shield of an armadillo and the dense furry coat of an Arctic bear to the slimy, scaled covering of a cod and the exceptionally smooth skin of a porpoise. Amphibians and fishes often have mucous glands that lubricate their skins and prevent waterlogging and deterioration. Reptiles have thick, leathery skins that help reduce water loss and serve as an armour against enemies. Birds use their feathers—skin derivatives—to fly and to insulate their bodies. The hairy or furry coats of many terrestrial mammals insulate them, shed water, and provide a dense guard against injury.

Invertebrate integuments

Components

The integuments of unicellular organisms comprise the cell membrane and any coating it secretes. Almost all bacteria have an external cell wall that maintains the shape and turgidity of the cell and affords protection. Multicellular invertebrates, however, have a single outer layer of epithelial cells, and these may secrete a variety of surface coatings, ranging from the mucous coat of cnidarians (polyps, sea anemones, jellyfish) to the tough cuticle of insects. The epithelial layer may include cells of several types, such as sensory cells, gland cells, and stinging cells, and the outer surfaces may bear microvilli, cilia, or other fine projections. In addition, the cells may produce excrescences such as bristles, spines, knobs, and ridges.

The firmness of some invertebrate animals, such as annelids (earthworms, marine worms, and leeches) and certain mollusks, depends on the distension by water of the individual cells that form the body wall. In many other forms rigid skeletal materials are deposited either within the cells or on the outer surface. The noncellular coatings of invertebrate integuments are exceedingly varied in composition and extent, and they cut across taxonomic categories. These rigid structures may provide no more than a protective armour, but in the arthropods, including crustaceans, insects, and spiders, a multilayered and hardened integument forms an exoskeleton to which muscles are attached. In the echinoderms, the exoskeleton lies below the epidermis.

Integument

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Invertebrate integuments

Components