The Individual Layers of Skin and Their Functions

Details about the body's largest organ

Moisturiser isn't just for the face
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The skin is the largest organ of the body and one of its most complicated. The skin is made up of many specialized cells and structures that are ever-changing.

The skin's primary function is to act as a barrier against disease-causing pathogens and hostile environments. It also helps regulate body temperature and gathers sensory information from the surrounding environment. Moreover, it plays an active role in the body's immune response to anything it considers harmful.

layers of the skin
 Verywell / Alexandra Gordon

The article takes a deeper look at how the skin functions and provides a better understanding of what each of the three layers—the epidermis, dermis, and subcutaneous tissue—actually do.

The Epidermis

The epidermis is the outermost layer of the skin. Its thickness depends on where it is located on the body. It is thinnest on the eyelids (roughly half a millimeter) and thickest on the palms and soles (1.5 millimeters).

The epidermis is made up of five individual layers:

  • Stratum basale: This bottom layer, also known as the basal cell layer, has column-shaped cells that push older cells toward the surface. As the cells move upward, they start to flatten and die. The layer is also made up of melanocytes (that produce a pigment that gives the skin its color) and Merkel cells that act as receptors to touch.
  • Stratum spinosum: This layer, also known as the squamous cell layer, is the thickest part of the epidermis. It contains newly formed keratinocytes (that produce a protein called keratin that makes up hair, skin, and nails) as well as Langerhans cells that help fight infection.
  • Stratum granulosum: This layer contains more keratinocytes that are gradually pushed toward the surface of the skin.
  • Stratum lucidum: This translucent layer of tissue exists only on the palms of the hands and soles of the feet. 
  • Stratum corneum: This is the top layer of the epidermis that helps the skin retain moisture and prevents unwanted substances from entering the body. It is made of dead, flattened keratinocytes that are shed approximately every two weeks.

Recap

The epidermis is the outermost layer of skin that protects the body from the outside world, keeps the skin hydrated, produces new skin cells, and gives skin its color.

The Dermis

The dermis is the middle layer of the skin. It contains connective tissue, capillaries, nerve endings, and hair follicles. It also contains different glands, including sebaceous glands that produce sebum (a body oil) and apocrine glands that produce sweat.

The dermis is split into two parts:

  • Papillary dermis: This is the thin, upper layer that contains capillaries that help regulate skin temperature and provide nutrients to the epidermis. They also contain Meissner corpuscles (that transmit sensations of delicate touch) and lamellar corpuscles (that transmit sensations of vibration and pressure).
  • Reticular dermis: This is the thick, lower layer that contains connective tissues and dense collagen bundles that provide the skin with its overall elasticity and strength.

The thickness of the dermis varies by its location on the body. On the eyelids, it is roughly 0.6 millimeters thick. On the back, palms of hands, and soles of the feet, it is 3 millimeters thick.

Recap

The role of the dermis is to support and strengthen the skin, regulate skin temperature, nourish and moisturize the epidermis, and aid with sensations.

Subcutaneous Tissue

Subcutaneous tissue is the innermost layer of the skin. It is mostly made up of fat, connective tissues, larger blood vessels, and nerves.

The majority of your body fat is stored in the subcutaneous layer. It not only insulates you against changing temperatures but protects your muscles and internal organs from impacts and falls.

The subcutaneous layer also:

  • Stores fat cells for energy reserves
  • Gives the body its smooth, contoured appearance
  • Regulates temperature through the contraction and dilation of blood vessels
  • Serves as the attachment point for bones, muscles, and other organs to the skin
  • Contains deep pressure sensors
  • Produces a hormone called leptin that helps keep the body's metabolism in homeostasis (equilibrium)

Recap

The subcutaneous tissue insulates the body and helps regulate body temperature. In addition to storing energy, it protects the body from impacts and connects the skin to muscles, bones, and other organs.

Summary

The skin is the body's largest organ. It is made of three layers, each of which has specific functions.

The outermost epidermis is responsible for producing new skin cells, protecting the body from unwanted substances, and retaining moisture to keep the skin well hydrated.

The middle dermis is responsible for supporting and strengthening the skin. It helps keep the skin moisturized and nourishes the epidermis. It also aids with fine sensations and helps regulate the skin temperature.

The innermost subcutaneous tissue insulates the body against changes in temperature and physical impacts. It gives the body its contoured shape and connects the skin to the internal organs. It also stores fat cells for energy and helps regulates the body temperature,

Frequently Asked Questions

  • How many layers of skin are there?

    There are three main layers of skin:

    • Epidermis: The outermost layer, which contains five sub-layers
    • Dermis: The middle layer, which consists of two parts known as the papillary dermis (thin, upper layer) and the reticular dermis (thick, lower layer)
    • Subcutaneous tissue: The deepest layer of skin
  • What is the integumentary system?

    The integumentary system is a collection of organs that includes the skin, hair, nails, endocrine glands, and sensory nerves. The primary function of this system is to protect the body from external elements, such as bacteria or pollution.

  • Which layers of the skin are affected by third-degree burns?

    Third-degree burns affect all layers of skin: the epidermis, dermis, and subcutaneous tissue. These burns may require skin grafting treatments, since the damage is so severe that the skin might be unable to repair itself.

  • When getting tattooed, which layer of the skin is the ink injected into?

    Tattoo needles penetrate the epidermis and place ink into the dermis, about 2 millimeters below the skin’s topmost layer. Injecting the pigment this deeply prevents the ink from wearing away so it can remain permanently visible.

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7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • Kumar V, Abbas AK, Aster JC. Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders.