Table of ContentsView AllTable of ContentsThe EpidermisThe DermisHypodermis
Table of ContentsView All
View All
Table of Contents
The Epidermis
The Dermis
Hypodermis
The number of skin layers that exists depends on how you count them. You have three main layers of skin—theepidermis,dermis,andhypodermis(subcutaneous tissue). Within these layers are additional layers. If you count the layers within the layers, the skin has eight or even 10 layers.
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Skin is the largest organ in the body and is quite complex. Its primary function is to act as a barrier against disease-causingpathogens(germs) and hostile environments. It also helps regulate body temperature and gathers sensory information from your environment.
This article looks at the three main layers of skin and the layers within them. It explains the different types of tissue found in the layers of the skin and the conditions that affect them.
Verywell / Alexandra Gordon
The epidermis is the outermost skin layer. Its thickness depends on where it is on the body. It’s thinnest on the eyelids (roughly half a millimeter) and thickest on your palms and soles (1.5 millimeters).
Conditions and disorders that affect the epidermis include:
It is made up of the following five layers.
Stratum Corneum
Thestratum corneumis the top layer of the epidermis. Its jobs are to:
It is made of dead, flattened cells calledkeratinocytesthat are shed approximately two weeks after they enter this layer. Keratinocytes produce keratin, a fibrous protein that helps provide structure to your skin, hair, and nails.
Stratum Lucidum
Thestratum lucidumis a separate layer only in the thicker epidermis on the palms of the hands and soles of the feet. In thinner areas, its cells and functions are incorporated into other layers.
The stratum lucidum:
This layer is also made of dead, flattened keratinocytes. The name comes from it appearing clear or “lucid” when examined microscopically.
Stratum Granulosum
Thestratum granulosumlayer contains keratinocytes that are gradually being pushed toward the surface of the skin. While moving through this layer, cells start to lose their structure and characteristic and become more like the dead, flattened keratinocytes of the outermost layers.
This skin layer also contains lipids (a type of fatty acid) that help form a waterproof barrier that prevents your body from losing fluid through the skin.
Stratum Spinosum
Thestratum spinosum, orsquamouscell layer, is the thickest part of the epidermis. It contains:
This is the main barrier that keeps foreign substances in the environment from getting into your body.
Stratum Basale
Also called the basal cell layer, thestratum basaleis the bottom layer of the epidermis. It contains several important types of cells:
What Is the Function of the Epidermis?
The dermis is the middle layer of the skin. It contains connective tissue, capillaries, nerve endings, andhair follicles. It also contains different glands, includingsebaceous glandsthat produce sebum (a body oil) and eccrine glands that produce sweat.
Conditions and disorders that affect the dermis layer include:
The dermis is split into two parts.
Papillary Dermis
Thepapillarydermis is the thin upper layer directly beneath the epidermis. The junction of the two is called the dermoepidermal junction (DEJ). It contains capillaries (tiny blood vessels) that help regulate skin temperature and provide nutrients to the epidermis.
This skin layer also contains the following:
Reticular Dermis
The reticular dermis is the thick, lower layer that contains connective tissues and densecollagenbundles.
Collagen is the main protein that provides structure to skin and connective tissues. It gives skin elasticity and strength.
What Is the Function of the Dermis?
The innermost layer of the skin is the hypodermis. Also known as subcutaneous tissue, it’s mostly made up of:
The majority of your body fat is stored in the subcutaneous layer. It insulates you against changing temperatures and protects your muscles and internal organs from impacts and falls.
In medical shorthand, subcutaneous is abbreviated SQ. An SQ injection is delivered to the subcutaneous layer.
The hypodermis layer also does the following:
Conditions that affect the subcutaneous layer of the skin include:
What Is the Function of Subcutaneous Tissue?
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,
6 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Abdo J, Sopko N, Milner S.The applied anatomy of human skin: A model for regeneration.Wound Medicine. 2020;28:100179. doi:10.1016/j.wndm.2020.100179Yousef H, Alhajj M, Sharma S.Anatomy, skin (integument), epidermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.Ono S, Kabashima K.Novel insights into the role of immune cells in skin and inducible skin-associated lymphoid tissue (iSALT).Allergo J Int. 2015;24:170-179. doi:10.1007/s40629-015-0065-1Brown TM, Krishnamurthy K.Histology, Dermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Histology, dermis.Shpichka A, Butnaru D, Bezrukov E, et al.Skin tissue regeneration for burn injury.Stem Cell Res Ther. 2019;10(1):94. doi:10.1186/s13287-019-1203-3Additional ReadingKumar V, Abbas AK, Aster JC.Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Anatomy, skin (integument),epidermis.
6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Abdo J, Sopko N, Milner S.The applied anatomy of human skin: A model for regeneration.Wound Medicine. 2020;28:100179. doi:10.1016/j.wndm.2020.100179Yousef H, Alhajj M, Sharma S.Anatomy, skin (integument), epidermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.Ono S, Kabashima K.Novel insights into the role of immune cells in skin and inducible skin-associated lymphoid tissue (iSALT).Allergo J Int. 2015;24:170-179. doi:10.1007/s40629-015-0065-1Brown TM, Krishnamurthy K.Histology, Dermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Histology, dermis.Shpichka A, Butnaru D, Bezrukov E, et al.Skin tissue regeneration for burn injury.Stem Cell Res Ther. 2019;10(1):94. doi:10.1186/s13287-019-1203-3Additional ReadingKumar V, Abbas AK, Aster JC.Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Anatomy, skin (integument),epidermis.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Abdo J, Sopko N, Milner S.The applied anatomy of human skin: A model for regeneration.Wound Medicine. 2020;28:100179. doi:10.1016/j.wndm.2020.100179Yousef H, Alhajj M, Sharma S.Anatomy, skin (integument), epidermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.Ono S, Kabashima K.Novel insights into the role of immune cells in skin and inducible skin-associated lymphoid tissue (iSALT).Allergo J Int. 2015;24:170-179. doi:10.1007/s40629-015-0065-1Brown TM, Krishnamurthy K.Histology, Dermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Histology, dermis.Shpichka A, Butnaru D, Bezrukov E, et al.Skin tissue regeneration for burn injury.Stem Cell Res Ther. 2019;10(1):94. doi:10.1186/s13287-019-1203-3
Abdo J, Sopko N, Milner S.The applied anatomy of human skin: A model for regeneration.Wound Medicine. 2020;28:100179. doi:10.1016/j.wndm.2020.100179
Yousef H, Alhajj M, Sharma S.Anatomy, skin (integument), epidermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
Ono S, Kabashima K.Novel insights into the role of immune cells in skin and inducible skin-associated lymphoid tissue (iSALT).Allergo J Int. 2015;24:170-179. doi:10.1007/s40629-015-0065-1
Brown TM, Krishnamurthy K.Histology, Dermis. In:StatPearls[Internet]. Treasure Island (FL): StatPearls Publishing; 2023.
National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Histology, dermis.
Shpichka A, Butnaru D, Bezrukov E, et al.Skin tissue regeneration for burn injury.Stem Cell Res Ther. 2019;10(1):94. doi:10.1186/s13287-019-1203-3
Kumar V, Abbas AK, Aster JC.Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders.National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Anatomy, skin (integument),epidermis.
Kumar V, Abbas AK, Aster JC.Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders.
National Institutes of Health, U.S. National Center For Biotechnology Information: StatPearls [Internet].Anatomy, skin (integument),epidermis.
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