stratum corneum

noun
stratum cor·​ne·​um | \ -ˈkȯr-nē-əm How to pronounce stratum corneum (audio) \

Definition of stratum corneum

: the outermost layer of the epidermis that consists of keratin-rich corneocytes connected by desmosomes and embedded in a matrix of lipids (such as ceramides and cholesterol) arranged in bilayers and that regulates skin permeability, maintains hydration, provides structural integrity, and acts as a protective barrier (as against UV radiation, pathogens, and toxins)

Note: In humans, the stratum corneum is typically 12 to 20 cell layers thick but may be over 50 layers thick in the soles of the feet and less than 9 layers thick on the eyelids. The outer layers are continually shed with one corneocyte cell layer typically sloughed off every day as desmosomes are enzymatically broken down.

The stratum corneum barrier relies predominantly on the extracellular matrix, where lamellar bilayers block the outflow of water into the environment … .— Peter M. Elias et al. A primary function of the stratum corneum is to protect the underlying tissue from environmental injury.Discover

Examples of stratum corneum in a Sentence

Recent Examples on the Web The top layer of our skin (the stratum corneum) is our skin’s key protective layer. Popular Science, "Simple tips to heal your hands after constant washing," 18 Apr. 2020 Ceramides Ceramides are an important part of the stratum corneum, the skin’s natural protective barrier. Sarah Jacoby, SELF, "7 Hydrating Skin-Care Ingredients That Will Actually Help Moisturize Dry, Dull Skin," 26 Feb. 2020 The outer layer of skin—the stratum corneum—functions as the skin’s main protective barrier. Sarah Jacoby, SELF, "Why Derms Swear By Colloidal Oatmeal for Dry, Irritated Skin," 15 Jan. 2020 In addition to helping maintain the stratum corneum (and therefore keep skin looking healthy and functioning well), there’s some evidence that EFAs can reduce the skin’s sensitivity to the sun. A.a. Newton, SELF, "Do You Really Need to Put Fatty Acids on Your Face?," 28 Aug. 2019 Together, the oils produced by your skin keep the layers of your skin soft, seal hydration in, and protect against allergens and pathogens by keeping the stratum corneum in tact. Jenn Sinrich, SELF, "What You Should Know Before Using a Trendy New Face Oil," 13 Mar. 2019 These acids are found in fats and oils but are also a key component of the stratum corneum, the outer protective layer of your skin. A.a. Newton, SELF, "Do You Really Need to Put Fatty Acids on Your Face?," 28 Aug. 2019 But there are also other lipids (fats and oils) produced by cells in the stratum corneum, the protective outer layer of skin that functions as the skin’s primary protection against losing water. Jenn Sinrich, SELF, "What You Should Know Before Using a Trendy New Face Oil," 13 Mar. 2019 Together, these things create a protective coating on top of the stratum corneum, the protective outer layer of skin. Sarah Jacoby, SELF, "What the Heck Is Squalane Oil and Why Is It Suddenly in All My Skin-Care Products?," 20 June 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'stratum corneum.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of stratum corneum

1857, in the meaning defined above

History and Etymology for stratum corneum

New Latin, literally, horny layer

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The first known use of stratum corneum was in 1857

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Cite this Entry

“Stratum corneum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/stratum%20corneum. Accessed 27 Oct. 2020.

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More Definitions for stratum corneum

stratum corneum

noun
plural strata cornea

Medical Definition of stratum corneum

: the outer more or less horny part of the epidermis consisting chiefly of layers of dead flattened nonnucleated cells filled with keratin

More from Merriam-Webster on stratum corneum

Britannica.com: Encyclopedia article about stratum corneum

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