The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis. The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix. It also contains mechanoreceptors that provide the sense of touch and thermoreceptors that provide the sense of heat. In addition, hair follicles, sweat glands, sebaceous glands (oil glands), apocrine glands, lymphatic vessels, nerves and blood vessels are present in the dermis. Those blood vessels provide nourishment and waste removal for both dermal and epidermal cells.
| Dermis | |
|---|---|
 Cross-section of human skin | |
 Cross section of skin under a microscope | |
| Details | |
| Part of | Skin |
| Identifiers | |
| MeSH | D020405 |
| TA98 | A16.0.00.010 |
| TA2 | 7047 |
| TH | H3.12.00.1.03001 |
| FMA | 70323 |
| Anatomical terminology [edit on Wikidata] | |
Structure
The dermis is composed of three major types of cells:fibroblasts, macrophages, and mast cells.
Apart from these cells, the dermis is also composed of matrix components such as collagen (which provides strength), elastin (which provides elasticity), and extrafibrillar matrix, an extracellular gel-like substance primarily composed of glycosaminoglycans (most notably hyaluronan), proteoglycans, and glycoproteins.
Layers
Papillary dermis
The papillary dermis is the uppermost layer of the dermis. It intertwines with the rete ridges of the epidermis and is composed of fine and loosely arranged collagen fibers. The papillary region is composed of loose areolar connective tissue. It is named for its fingerlike projections called papillae or dermal papillae specifically, that extend toward the epidermis and contain either terminal networks of blood capillaries or tactile Meissner's corpuscles.
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Epidermis, papillary dermis and reticular dermis.
Dermal papillae
| Dermal papillae | |
|---|---|
  Papilla of the hand, treated with acetic acid. Magnified 350 times. A. Side view of a papilla of the hand. a. Cortical layer. b. Tactile corpuscle. c. Small nerve of the papilla, with neurolemma. d. Its two nervous fibers running in spiral coils around the tactile corpuscle. e. Apparent termination of one of these fibers. B. Tactile papilla seen from above so as to show its transverse section. a. Cortical layer. b. Nerve fiber. c. Outer layer of the tactile body, with nuclei. d. Clear interior substance. | |
| Details | |
| Identifiers | |
| Latin | papillae dermis |
| MeSH | D020405 |
| TA98 | A16.0.00.010 |
| TA2 | 7047 |
| TH | H3.12.00.1.03001 |
| FMA | 70323 |
| Anatomical terminology [edit on Wikidata] | |
The dermal papillae (DP) (singular papilla, diminutive of Latin papula, 'pimple') are small, nipple-like extensions (or interdigitations) of the dermis into the epidermis. At the surface of the skin in hands and feet, they appear as epidermal, papillary or friction ridges (colloquially known as fingerprints).
Blood vessels in the dermal papillae nourish all hair follicles and bring nutrients and oxygen to the lower layers of epidermal cells. The pattern of ridges produced in hands and feet are only partly genetically determined features that are developed before birth, the timing and events around the ridge formation area also contributing. They remain substantially unaltered (except in size) throughout life, and therefore determine the patterns of fingerprints, making them useful in certain functions of personal identification.
The dermal papillae are part of the uppermost layer of the dermis, the papillary dermis, and the ridges they form greatly increase the surface area between the dermis and epidermis. Because the main function of the dermis is to support the epidermis, this greatly increases the exchange of oxygen, nutrients, and waste products between these two layers. Additionally, the increase in the surface area prevents the dermal and epidermal layers from separating by strengthening the junction between them. With age, the papillae tend to flatten and sometimes increase in number.
The skin of the hands and fingers and the feet and toes is known by forensic scientists as friction ridge skin. It is known by anatomists as thick skin, volar skin or hairless skin. It has raised ridges, a thicker and more complex epidermis, increased sensory abilities, and the absence of hair and sebaceous glands. The ridges increase friction for improved grasping.
Dermal papillae also play a pivotal role in hair formation, growth and cycling.
In mucous membranes, the equivalent structures to dermal papillae are generally termed "connective tissue papillae", which interdigitate with the rete pegs of the superficial epithelium. Dermal papillae are less pronounced in thin skin areas.
Reticular dermis
The reticular dermis is the lower layer of the dermis, found under the papillary dermis, composed of dense irregular connective tissue featuring densely-packed collagen fibers. It is the primary location of dermal elastic fibers.
The reticular region is usually much thicker than the overlying papillary dermis. It receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it. These protein fibers give the dermis its properties of strength, extensibility, and elasticity. Within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels. The orientation of collagen fibers within the reticular dermis creates lines of tension called Langer's lines, which are of some relevance in surgery and wound healing.
See also
- List of cutaneous conditions
References
- James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology (10th ed.). Saunders. Pages 1, 11–12. ISBN 0-7216-2921-0.
- Marks, James G; Miller, Jeffery (2006). Lookingbill and Marks' Principles of Dermatology (4th ed.). Elsevier Inc. Page 8–9. ISBN 1-4160-3185-5.
- malvi (4 March 2011). "The Ageing Skin - Part 1 - Structure of Skin and Introduction - Articles". PharmaXChange.info.
- http://microvet.arizona.edu/Courses/vsc422/secure/VSC422AppledHistologyLabHandout.pdf[permanent dead link]
- Meuwly, Didier (2013-12-04). "Friction Ridge Skin—Automated Fingerprint Identification System (<scp>AFIS</scp>)". Wiley Encyclopedia of Forensic Science: 1–8. doi:10.1002/9780470061589.fsa359.pub2.
- "Dermal papillae". Probert Encyclopaedia. Archived from the original on 2011-06-08.
- "Friction Skin". Ridges and Furrows. Archived from the original on 2021-04-22. Retrieved 2016-12-23.
- Hicklin, R. Austin (2009). "Anatomy of Friction Ridge Skin". Encyclopedia of Biometrics. Springer US. pp. 23–28. doi:10.1007/978-0-387-73003-5_48. ISBN 978-0-387-73002-8.
- Lin, Chang-min; et al. (October 2008). "Microencapsulated human hair dermal papilla cells: a substitute for dermal papilla?". Archives of Dermatological Research. 300 (9). Springer: 531–535. doi:10.1007/s00403-008-0852-3. PMID 18418617. S2CID 21632556.
- Ross M, Pawlina W (2011). Histology: A Text and Atlas (6th ed.). Lippincott Williams & Wilkins. p. 498. ISBN 978-0-7817-7200-6.
The dermis or corium is a layer of skin between the epidermis with which it makes up the cutis and subcutaneous tissues that primarily consists of dense irregular connective tissue and cushions the body from stress and strain It is divided into two layers the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis The dermis is tightly connected to the epidermis through a basement membrane Structural components of the dermis are collagen elastic fibers and extrafibrillar matrix It also contains mechanoreceptors that provide the sense of touch and thermoreceptors that provide the sense of heat In addition hair follicles sweat glands sebaceous glands oil glands apocrine glands lymphatic vessels nerves and blood vessels are present in the dermis Those blood vessels provide nourishment and waste removal for both dermal and epidermal cells DermisCross section of human skinCross section of skin under a microscopeDetailsPart ofSkinIdentifiersMeSHD020405TA98A16 0 00 010TA27047THH3 12 00 1 03001FMA70323Anatomical terminology edit on Wikidata StructureThe dermis is composed of three major types of cells fibroblasts macrophages and mast cells Apart from these cells the dermis is also composed of matrix components such as collagen which provides strength elastin which provides elasticity and extrafibrillar matrix an extracellular gel like substance primarily composed of glycosaminoglycans most notably hyaluronan proteoglycans and glycoproteins LayersIllustration of dermal circulation and layersPapillary dermis The papillary dermis is the uppermost layer of the dermis It intertwines with the rete ridges of the epidermis and is composed of fine and loosely arranged collagen fibers The papillary region is composed of loose areolar connective tissue It is named for its fingerlike projections called papillae or dermal papillae specifically that extend toward the epidermis and contain either terminal networks of blood capillaries or tactile Meissner s corpuscles Epidermis papillary dermis and reticular dermis Dermal papillae Dermal papillaePapilla of the hand treated with acetic acid Magnified 350 times A Side view of a papilla of the hand a Cortical layer b Tactile corpuscle c Small nerve of the papilla with neurolemma d Its two nervous fibers running in spiral coils around the tactile corpuscle e Apparent termination of one of these fibers B Tactile papilla seen from above so as to show its transverse section a Cortical layer b Nerve fiber c Outer layer of the tactile body with nuclei d Clear interior substance DetailsIdentifiersLatinpapillae dermisMeSHD020405TA98A16 0 00 010TA27047THH3 12 00 1 03001FMA70323Anatomical terminology edit on Wikidata The dermal papillae DP singular papilla diminutive of Latin papula pimple are small nipple like extensions or interdigitations of the dermis into the epidermis At the surface of the skin in hands and feet they appear as epidermal papillary or friction ridges colloquially known as fingerprints Blood vessels in the dermal papillae nourish all hair follicles and bring nutrients and oxygen to the lower layers of epidermal cells The pattern of ridges produced in hands and feet are only partly genetically determined features that are developed before birth the timing and events around the ridge formation area also contributing They remain substantially unaltered except in size throughout life and therefore determine the patterns of fingerprints making them useful in certain functions of personal identification The dermal papillae are part of the uppermost layer of the dermis the papillary dermis and the ridges they form greatly increase the surface area between the dermis and epidermis Because the main function of the dermis is to support the epidermis this greatly increases the exchange of oxygen nutrients and waste products between these two layers Additionally the increase in the surface area prevents the dermal and epidermal layers from separating by strengthening the junction between them With age the papillae tend to flatten and sometimes increase in number The skin of the hands and fingers and the feet and toes is known by forensic scientists as friction ridge skin It is known by anatomists as thick skin volar skin or hairless skin It has raised ridges a thicker and more complex epidermis increased sensory abilities and the absence of hair and sebaceous glands The ridges increase friction for improved grasping Dermal papillae also play a pivotal role in hair formation growth and cycling In mucous membranes the equivalent structures to dermal papillae are generally termed connective tissue papillae which interdigitate with the rete pegs of the superficial epithelium Dermal papillae are less pronounced in thin skin areas Reticular dermis The reticular dermis is the lower layer of the dermis found under the papillary dermis composed of dense irregular connective tissue featuring densely packed collagen fibers It is the primary location of dermal elastic fibers The reticular region is usually much thicker than the overlying papillary dermis It receives its name from the dense concentration of collagenous elastic and reticular fibers that weave throughout it These protein fibers give the dermis its properties of strength extensibility and elasticity Within the reticular region are the roots of the hair sebaceous glands sweat glands receptors nails and blood vessels The orientation of collagen fibers within the reticular dermis creates lines of tension called Langer s lines which are of some relevance in surgery and wound healing See alsoList of cutaneous conditionsReferencesJames William Berger Timothy Elston Dirk 2005 Andrews Diseases of the Skin Clinical Dermatology 10th ed Saunders Pages 1 11 12 ISBN 0 7216 2921 0 Marks James G Miller Jeffery 2006 Lookingbill and Marks Principles of Dermatology 4th ed Elsevier Inc Page 8 9 ISBN 1 4160 3185 5 malvi 4 March 2011 The Ageing Skin Part 1 Structure of Skin and Introduction Articles PharmaXChange info http microvet arizona edu Courses vsc422 secure VSC422AppledHistologyLabHandout pdf permanent dead link Meuwly Didier 2013 12 04 Friction Ridge Skin Automated Fingerprint Identification System lt scp gt AFIS lt scp gt Wiley Encyclopedia of Forensic Science 1 8 doi 10 1002 9780470061589 fsa359 pub2 Dermal papillae Probert Encyclopaedia Archived from the original on 2011 06 08 Friction Skin Ridges and Furrows Archived from the original on 2021 04 22 Retrieved 2016 12 23 Hicklin R Austin 2009 Anatomy of Friction Ridge Skin Encyclopedia of Biometrics Springer US pp 23 28 doi 10 1007 978 0 387 73003 5 48 ISBN 978 0 387 73002 8 Lin Chang min et al October 2008 Microencapsulated human hair dermal papilla cells a substitute for dermal papilla Archives of Dermatological Research 300 9 Springer 531 535 doi 10 1007 s00403 008 0852 3 PMID 18418617 S2CID 21632556 Ross M Pawlina W 2011 Histology A Text and Atlas 6th ed Lippincott Williams amp Wilkins p 498 ISBN 978 0 7817 7200 6
