Dermis - Wikipedia

Layer of skin between the epidermis and subcutaneous tissues

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]

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.[1] The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix.[2] 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.

Structure

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The dermis is composed of three major types of cells:[3] 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.[3]

Layers

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Papillary dermis

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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.[2] 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.[4]

• Epidermis, papillary dermis and reticular dermis.

Dermal papillae

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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). Note that dermal papilla has two meanings referring to separate anatomical features. The dermal papilla of the dermal–epidermal junction should not be confused with the dermal papilla cells at the base of each hair follicle.

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.[5] 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.[6]

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.[7]

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.[8]

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

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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.[2]

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.[9]

See also

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• List of cutaneous conditions

References

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1. ^ 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.
2. ^ a b c Marks, James G; Miller, Jeffery (2006). Lookingbill and Marks' Principles of Dermatology (4th ed.). Elsevier Inc. Page 8–9. ISBN 1-4160-3185-5.
3. ^ a b malvi (4 March 2011). "The Ageing Skin - Part 1 - Structure of Skin and Introduction - Articles". PharmaXChange.info.
4. ^ http://microvet.arizona.edu/Courses/vsc422/secure/VSC422AppledHistologyLabHandout.pdf[permanent dead link]
5. ^ Meuwly, Didier (2013-12-04). "Friction Ridge Skin—Automated Fingerprint Identification System (AFIS)". Wiley Encyclopedia of Forensic Science. pp. 1–8. doi:10.1002/9780470061589.fsa359.pub2. ISBN 978-0-470-01826-2.
6. ^ "Dermal papillae". Probert Encyclopaedia. Archived from the original on 2011-06-08.
7. ^ "Friction Skin". Ridges and Furrows. Archived from the original on 2021-04-22. Retrieved 2016-12-23.
8. ^ 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.
9. ^ Ross M, Pawlina W (2011). Histology: A Text and Atlas (6th ed.). Lippincott Williams & Wilkins. p. 498. ISBN 978-0-7817-7200-6.

v t e Skin and related structures
Skin	Epidermis Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Malpighian layer Stratum basale Basement membrane Basal keratinocyte Lamina lucida Lamina densa Dermis Papillary Dermal papillae Reticular
Subcutaneous tissue	Panniculus/Pannus (Panniculus adiposus Panniculus carnosus) Membranous layer Loose connective tissue Superficial fascia
Adnexa	Skin glands Sweat glands: Apocrine sweat gland Eccrine sweat gland Sebaceous Hair Root sheath Outer root sheath Inner root sheath Henle's layer Huxley's layer Hair shaft Cuticle Cortex Medulla Bulb with matrix cells Hair follicle Muscle Arrector pili muscle Pilosebaceous unit Hair sebaceous gland Nail Nail matrix Nail plate Lunula Eponychium Paronychium Hyponychium

v t e Connective tissue
Physiology	Soft tissue Fibrosis Scarring
Composition	Cells Resident Fibroblast Fibrocyte Reticular cell Tendon cell Adipocyte Melanocyte Wandering cells Mast cell Macrophage Extracellular matrix Ground substance Tissue fluid Fibers Collagen fibers Reticular fibers COL3A1 Elastic fibers Elastin Fibrillin FBN1 FBN2 FBN3 EMILIN1 Elaunin
Types	Proper Loose Reticular Adipose Brown White Dense Dense irregular connective tissue Submucosa Dermis Dense regular connective tissue Ligament Tendon Aponeurosis Embryonic Mucoid Mesenchymal Specialized Cartilage Elastic Hyaline Fibrocartilage Bone Blood

v t e Routes of administration, dosage forms
Oral	Digestive tract (enteral) Solids Tablet Capsule Pastille Time release technology Osmotic delivery system Liquids Decoction Elixir Electuary Emulsion Effervescent powder or tablet Herbal tea Hydrogel Molecular encapsulation Powder Softgel Solution Suspension Syrup Tincture Oral mucosa (buccal, sublabial, sublingual, supralingual) Solids Orally disintegrating tablet Film Lollipop Sublingual drops Lozenges Effervescent tablet Chewing gum Liquids Mouthwash Toothpaste Ointment Spray Respiratory tract (inhalation) Solids Dry-powder inhaler Smoking 00 Liquids Anesthetic vaporizer Heated humidified high-flow therapy Medical inhalants Metered-dose inhaler (MDI) Nebulizer Vaporizer Gas Oxygen mask and Nasal cannula Oxygen concentrator Anaesthetic machine Medical inhalants Relative analgesia machine
Ophthalmic,otic, nasal	Nasal spray Ear drops Eye drops Ointment Hydrogel Insufflation Mucoadhesive microdisc
Urogenital	Ointment Pessary Vaginal ring Douche Intrauterine device (IUD) Extra-amniotic infusion Intravesical infusion
Rectal (enteral)	Ointment Suppository Enema Solution Hydrogel Murphy drip Nutrient enema
Dermal (topical)	Ointment Topical cream Topical gel Liniment Paste Film DMSO solution Iontophoresis Hydrogel Liposomes Transfersome vesicles Cream Lotion Lip balm Medicated shampoo Dermal patch Transdermal patch Transdermal spray Jet injector
Parenterals, injections,infusions(into tissue/blood)	Skin (transdermal) Intradermal Subcutaneous Injector pen Transdermal implant Organs Intracavernous Intravitreal Intra-articular Central nervous system Intracerebral Intrathecal Epidural Circulatory,musculoskeletal Intravenous Intracardiac Intramuscular Intraosseous Intraperitoneal Nanocell injection Patient-controlled analgesia pump PIC line

Authority control databases	Terminologia Anatomica