FACTOID # 24: Looking for table makers? Head to Mississippi, with an overwhlemingly large number of employees in furniture manufacturing.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Epithelium" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Epithelium
Types of epithelium
Types of epithelium

In biology and medicine, epithelium is a tissue composed of a layer of cells. Epithelium lines both the outside (skin) and the inside cavities and lumen of bodies. The outermost layer of our skin is composed of dead stratified squamous, keratinized epithelial cells. The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruiting body. ... Image File history File linksMetadata Illu_epithelium. ... Image File history File linksMetadata Illu_epithelium. ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Beyond overall skin structure, refer below to: See-also. ... artery anatomy, showing lumen The lumen (pl. ... Beyond overall skin structure, refer below to: See-also. ... Stratification is the building up of layers of deposits, and can have several variations of meaning: Social stratification, is the dividing of a society into levels based on wealth or power. ... Squamous means covered with or formed of scales; scaly. ... Epidermis is the outermost layer of the skin. ...


Mucous membranes lining the inside of the mouth, the esophagus, and part of the rectum are lined by nonkeratinized stratified squamous epithelium. Other, open to outside body cavities are lined by simple squamous or columnar epithelial cells. The mucous membranes (or mucosa) are linings of ectodermic origin, covered in epithelium, that line various body cavities and internal organs. ...


Other epithelial cells line the insides of the lungs, the gastrointestinal tract, the reproductive and urinary tracts, and make up the exocrine and endocrine glands. The outer surface of the cornea is covered with fast-growing, easily-regenerated epithelial cells. Human respiratory system The lungs flank the heart and great vessels in the chest cavity. ... Upper and Lower gastrointestinal tract The gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... Exocrine gland refers to glands that secrete their products via a duct. ... The endocrine system is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ...


Functions of epithelial cells include secretion, absorption, protection, transcellular transport, sensation detection, and selective permeability.


Endothelium (the inner lining of blood vessels, the heart, and lymphatic vessels) is a specialized form of epithelium. Another type, Mesothelium, forms the walls of the pericardium, pleurae, and peritoneum. The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... f you all The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... The heart and lungs, from an older edition of Grays Anatomy. ... In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... The mesothelium is a membrane that forms the lining of several body cavities: the pleura (thoracal cavity), peritoneum (abdominal cavity) and pericardium (heart sac). ... The pericardium is a double-walled sac that contains the heart and the roots of the great vessels. ... “Pleura” redirects here. ... In higher vertebrates, the peritoneum is the serous membrane that forms the lining of the abdominal cavity - it covers most of the intra-abdominal organs. ...


In humans, epithelium is classified as a primary body tissue, the other ones being connective tissue, muscle tissue and nervous tissue. Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ... A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... Nervous tissue is the fourth major class of vertebrate tissue. ...

Contents

Classification

Epithelial cells are classified by the following three factors:

  • Shape
  • Stratification
  • Specializations

Shape

  • Squamous: Squamous cells are flat cells with an irregular flattened shape. A one-cell layer of simple squamous epithelium forms the alveoli of the respiratory membrane, and the endothelium of capillaries, and is a minimal barrier to diffusion. Other places where squamous cells can be found include the filtration tubules of the kidneys, and the major cavities of the body. These cells are relatively inactive metabolically, and are associated with the diffusion of water, electrolytes, and other substances.
  • Cuboidal: As the name suggests, these cells have a shape similar to a cube, meaning its width is the same size as its height. The nuclei of these cells are usually located in the center.
  • Columnar: These cells are taller than they are wide. Simple columnar epithelium is made up of a single layer of cells that are longer than they are wide. The nucleus is also closer to the base of the cell. The small intestine is a tubular organ lined with this type of tissue. Unicellular glands called goblet cells are scattered throughout the simple columnar epithelial cells and secrete mucus. The free surface of the columnar cell has tiny hairlike projections called microvilli. They increase the surface area for absorption.

The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... diffusion (disambiguation). ... Kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ... An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ... HeLa cells stained for DNA with the Blue Hoechst dye. ... In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and includes the duodenum, jejunum, and ileum. ... Åž:For other uses, see Organ (disambiguation) In biology, an organ (Latin: organum, instrument, tool) is a group of tissues that perform a specific function or group of functions. ... Mucus is a slippery secretion of the lining of various membranes in the body. ... Categories: Stub ...

Stratification

  • Simple: There is a single layer of cells.
  • Stratified: More than one layer of cells. The superficial layer is used to classify the layer. Only one layer touches the basal lamina. Stratified cells can usually withstand large amounts of stress.
  • Pseudostratified with cilia: This is used mainly in one type of classification (pseudostratified columnar epithelium). There is only a single layer of cells, but the position of the nuclei gives the impression that it is stratified. If a specimen looks stratified, but you can identify cilia, the specimen is pseudostratified ciliated epithelium since stratified epithelium cannot have cilia but may be very rarely found in fetal oesophagus. A cell that contains hairs will be around ten times stronger than a regular cell

The basal lamina (often erroneously called basement membrane) is a layer on which epithelium sits. ...

Specializations

  • Keratinized cells contain keratin (a cytoskeletal protein). While keratinized epithelium occurs mainly in the skin, it is also found in the mouth and nose, providing a tough, impermeable barrier.

Not to be confused with kerogen or carotene. ... Not to be confused with kerogen or carotene. ... The eukaryotic cytoskeleton. ... male human mouth The mouth, also known as the buccal cavity or the oral cavity, is the orifice through which an organism takes in food and water. ... For other uses, see Nose (disambiguation). ... cross-section of two cilia, showing 9+2 structure A cilium (plural cilia) is a fine projection from a eukaryotic cell that constantly beats in one direction. ... Alpha intercalated cell The apical membrane of a polarized cell is the part of the plasma membrane that forms its lumenal surface, distinct from the basolateral membrane. ... Drawing of a cell membrane A component of every biological cell, the cell membrane (or plasma membrane) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Microtubules are one of the components of the cytoskeleton. ... Mucus is a slippery secretion of the lining of various membranes in the body. ... The Respiratory System Among four-legged animals, the respiratory system generally includes tubes, such as the bronchi, used to carry air to the lungs, where gas exchange takes place. ... In oviparous animals (those that lay eggs), the passage from the ovaries to the outside of the body is known as the oviduct. ...

Examples

System Tissue Epithelium Subtype
circulatory blood vessels Simple squamous endothelium
digestive ducts of submandibular glands Stratified columnar -
digestive attached gingiva Stratified squamous, keratinized -
digestive dorsum of tongue Stratified squamous, keratinized -
digestive hard palate Stratified squamous, keratinized -
digestive esophagus Stratified squamous, non-keratinised -
digestive stomach Simple columnar, non-ciliated -
digestive small intestine Simple columnar, non-ciliated -
digestive large intestine Simple columnar, non-ciliated -
digestive rectum Stratified squamous, non-keratinised -
digestive anus Stratified squamous, keratinised -
digestive gallbladder Simple columnar, non-ciliated -
endocrine thyroid follicles Simple cuboidal -
nervous ependyma Simple cuboidal -
lymphatic lymph vessel Simple squamous endothelium
integumentary skin - dead superficial layer Stratified squamous, keratinized -
integumentary sweat gland ducts Stratified cuboidal -
integumentary mesothelium of body cavities Simple squamous -
reproductive - female ovaries Simple cuboidal germinal epithelium (female)
reproductive - female Fallopian tubes Simple columnar, ciliated -
reproductive - female uterus Simple columnar, ciliated -
reproductive - female endometrium Simple columnar -
reproductive - female cervix (endocervix) Simple columnar -
reproductive - female cervix (ectocervix) Stratified squamous, non-keratinised -
reproductive - female vagina Stratified squamous, non-keratinised -
reproductive - female labia majora Stratified squamous, keratinised -
reproductive - male tubuli recti Simple cuboidal germinal epithelium (male)
reproductive - male rete testis Simple cuboidal -
reproductive - male ductuli efferentes Pseudostratified columnar -
reproductive - male epididymis Pseudostratified columnar, with stereocilia -
reproductive - male vas deferens Pseudostratified columnar -
reproductive - male ejaculatory duct Simple columnar -
reproductive - male (gland) bulbourethral glands Simple columnar -
reproductive - male (gland) seminal vesicle Pseudostratified columnar -
respiratory oropharynx Stratified squamous, non-keratinised -
respiratory larynx Pseudostratified columnar, ciliated respiratory epithelium
respiratory trachea Pseudostratified columnar, ciliated respiratory epithelium
respiratory respiratory bronchioles Simple cuboidal -
sensory cornea Stratified squamous, non-keratinised corneal epithelium
sensory nose Pseudostratified columnar olfactory epithelium
urinary kidney - proximal convoluted tubule Simple columnar, ciliated -
urinary kidney - ascending thin limb Simple squamous -
urinary kidney - distal convoluted tubule Simple columnar, non-ciliated -
urinary kidney - collecting duct Simple cuboidal -
urinary renal pelvis Transitional urothelium
urinary ureter Transitional urothelium
urinary urinary bladder Transitional urothelium
urinary prostatic urethra Transitional urothelium
urinary membranous urethra Pseudostratified columnar, non-ciliated -
urinary penile urethra Pseudostratified columnar, non-ciliated -
urinary external urethral orifice Stratified squamous -

The blood vessels are part of the circulatory system and function to transport blood throughout the body. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... In anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ. ... The submandibular gland is one of the salivary glands, responsible for producing saliva. ... The gingiva (sing. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... The hard palate is a thin horizontal bony plate of the skull, otherwise known as the palatine process of the maxilla, located in the roof of the mouth. ... The esophagus (also spelled oesophagus/œsophagus, Greek ), or gullet is an organ in vertebrates which consists of a muscular tube through which food passes from the pharynx to the stomach. ... In anatomy, the stomach is a bean-shaped hollow muscular organ of the gastrointestinal tract involved in the second phase of digestion, following mastication. ... In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and includes the duodenum, jejunum, and ileum. ... It has been suggested that this article or section be merged with Colon (anatomy). ... The rectum (from the Latin rectum intestinum, meaning straight intestine) is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus. ... Female Human Anatomy Male Human Anatomy This article is about the bodily orifice. ... The gallbladder (or cholecyst, sometimes gall bladder) is a pear-shaped organ that stores about 50 ml of bile (or gall) until the body needs it for digestion. ... Ependyma is the thin epithelial membrane lining the ventricular system of the brain and the spinal cord canal. ... In anatomy, lymph vessels are thin walled, valved structures that carry lymph. ... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... Beyond overall skin structure, refer below to: See-also. ... In humans, there are four kinds of sudoriferous or sweat glands which differ greatly in both the composition of the sweat and its purpose. ... The mesothelium is a membrane that forms the lining of several body cavities: the pleura (thoracal cavity), peritoneum (abdominal cavity) and pericardium (heart sac). ... A body cavity is an aspect of a number of basic animal body plans (phyla) that incorporate a central body cavity, known as a coelom. ... Human female internal reproductive anatomy Ovaries are a part of a female organism that produces eggs. ... The surface of the ovary is covered by a layer of columnar cells which constitutes the germinal epithelium of Waldeyer. ... Female internal reproductive anatomy The Fallopian tubes or oviducts are two very fine tubes leading from the ovaries of female mammals into the uterus. ... This article is about female reproductive anatomy. ... The endometrium is the inner membrane of the mammalian uterus. ... The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... The cervix (from Latin neck) is the lower, narrow portion of the uterus where it joins with the top end of the vagina. ... The vagina, (from Latin, literally sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. ... Parts of a vulva The external genital organs of the female are collectively known as the vulva (also sometimes called the pudenda). ... The tubuli seminiferi recti (also known as the tubuli recti, tubulus rectus, or straight seminiferous tubules) is a structure in the testicle connecting the convoluted region of the seminiferous tubule to the rete testis, although the tubuli recti has a different appearance distinguishing it from these two structures. ... The germinal epithelium is the outermost layer of the testicle. ... Rete testis is an anastomosing network of delicate tubules located in the hilum of the testicle (mediastinum testis) that carries sperm from the seminiferous tubules to the vasa efferentia. ... The efferent ducts (or efferent ductules) are part of the testes and connect the rete testis with the epididymis. ... Male Anatomy The epididymis is part of the human male reproductive system and is present in all male mammals. ... Stereocilia are apical modifications of the cell, which are distinct from microvilli and cilia. ... The vas deferens (plural: vasa deferentia), also called ductus deferens, (Latin: carrying-away vessel) is part of the male anatomy of some species, including humans. ... The Ejaculatory ducts are part of the human male anatomy, which cause the reflex action of ejaculation. ... Male Anatomy In the anatomy of the male human body, the bulbourethral glands (or Cowpers glands) are two small, rounded, and somewhat lobulated bodies, of a yellow color, about the size of peas, placed behind and lateral to the membranous portion of the urethra, between the two layers of... The seminal vesicles are a pair of simple tubular glands posterinferior to the urinary bladder of males. ... The pharynx is the part of the digestive system of many animals immediately behind the mouth and in front of the esophagus. ... The larynx (plural larynges), colloquially known as the voicebox, is an organ in the neck of mammals involved in protection of the trachea and sound production. ... Respiratory epithelium is another name for ciliated pseudostratified columnar epithelium with goblet cells. ... The trachea, or windpipe, is a tube that has an inner diameter of about 12mm and a length of about 10-16cm. ... Respiratory epithelium is another name for ciliated pseudostratified columnar epithelium with goblet cells. ... A respiratory bronchiole is a bronchiole at the beginning of the respiratory zone. ... The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, providing most of an eyes optical power [1]. Together with the lens, the cornea refracts light and, as a result, helps the eye to focus. ... The corneal epithelium (epithelium corneæ anterior layer) covers the front of the cornea and consists of several layers of cells. ... For other uses, see Nose (disambiguation). ... The olfactory epithelium is a specialized epithelial tissue inside the nasal cavity that is involved in smell. ... The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... In the biology of the kidney, the proximal convoluted tubule is the segment of the renal tubule that drains Bowmans capsule. ... The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... As the filtrate passes back up the thin ascending limb of loop of Henle, the concentration of the surrounding medulla decreases. ... The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting duct system. ... The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ... The collecting duct system of the kidney consists of: The connecting tubule The cortical collecting duct The medullary collecting duct Categories: Urinary system ... The renal pelvis represents the dilated proximal part of the ureter. ... The urothelium is the lining of the ureters, urethra, and urinary bladder. ... Transverse section of ureter. ... The urothelium is the lining of the ureters, urethra, and urinary bladder. ... In anatomy, the urinary bladder is a hollow, muscular, and distensible (or elastic) organ that sits on the pelvic floor in mammals. ... The urothelium is the lining of the ureters, urethra, and urinary bladder. ... The prostatic urethra, the widest and most dilatable part of the canal, is about 3 cm. ... The urothelium is the lining of the ureters, urethra, and urinary bladder. ... The intermediate part of male urethra (membranous portion) is the shortest, least dilatable, and, with the exception of the external orifice, the narrowest part of the canal. ... The spongy urethra (cavernous portion of urethra, penile urethra) is the longest part of the urethra, and is contained in the corpus cavernosum urethraeæ. It is about 15 cm. ... The external urethral orifice (urinary meatus) is placed about 2. ...

Cell junctions

Main article: Cell junction

A cell junction is a structure within a tissue of a multicellular organism. Cell junctions are especially abundant in epithelial tissues. They consist of protein complexes and provide contact between neighbouring cells, between a cell and the extracellular matrix, or they built up the paracellular barrier of epithelia and control the paracellular transport. A cell junction is a structure within a tissue of a multicellular organism. ... Paracellular transport refers to the transfer of substances between cells of an epithelium. ...


Secretory epithelia

As stated above, secretion is one major function of epithelial cells. Glands are formed from the invagination / infolding of epithelial cells and subsequent growth in the underlying connective tissue. There are two major classification of glands: endocrine glands and exocrine glands. Endocrine glands are glands that secrete their product directly onto a surface rather than through a duct. This group contains the glands of the Endocrine system A gland is an organ in an animals body that synthesizes a substance for release such as hormones, often into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). ... An endocrine gland is one of a set of internal organs involved in the secretion of hormones into the blood. ... Exocrine gland refers to glands that secrete their products via a duct. ...


Embryology

Generally, there are epithelial tissues deriving from all of the embryological germ layers: Organs derived from each germ layer. ...

However, it is important to note that pathologists do not consider endothelium and mesothelium (both derived from mesoderm) to be true epithelium. This is because such tissues present very different pathology. For that reason, pathologists label cancers in endothelium and mesothelium sarcomas, while true epithelial cancers are called carcinomas. Also, the filaments that support these mesodermally derived tissues are very distinct. Outside of the field of pathology, the idea that epithelium arise from all three germ layers is generally accepted. The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ... Look up Epidermis in Wiktionary, the free dictionary. ... Endoderm is one of the germ layers formed during animal embryogenesis. ... Upper and Lower gastrointestinal tract The gastrointestinal tract (GI tract), also called the digestive tract, or the alimentary canal, is the system of organs within multicellular animals that takes in food, digests it to extract energy and nutrients, and expels the remaining waste. ... The mesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. ... A body cavity is an aspect of a number of basic animal body plans (phyla) that incorporate a central body cavity, known as a coelom. ... Max Bielschowsky Paul Ehrlich - (1854 - 1915) Gustav Giemsa - (1867 - 1948) (see Giemsa stain) Ludwig Grünwald William Boog Leishman - (1865 - 1926) (see leishmaniasis) Richard May Frank Burr Mallory (1862 - 1941) (see Mallory bodies) George Nicolas Papanicolaou (1883 - 1962) (see Pap smear) Artur Pappenheim Carl von Rokitansky Dmitri Leonidovich Romanowsky - (1861... The endothelium is the layer of thin, flat cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. ... The mesothelium is a membrane that forms the lining of several body cavities: the pleura (thoracal cavity), peritoneum (abdominal cavity) and pericardium (heart sac). ... A sarcoma is a cancer of the connective or supportive tissue (bone, cartilage, fat, muscle, blood vessels) and soft tissue. ... In medicine, carcinoma is any cancer that arises from epithelial cells. ...


Additional images

Image File history File links Tkanka_nablonkowa. ...

Links

References

  • Molecular Biology of the Cell, 4th edition, Alberts et al., 2002

  Results from FactBites:
 
Ocular Surface Epithelium (224 words)
Based on the unique keratin expression pattern of corneal epithelium, we proposed in 1986 that corneal epithelial stem cells reside in the limbus, a previously ignored, transitional zone between cornea and conjunctiva (J Cell Biol 1986).
The limbal stem cell concept explains why an earlier surgical procedure, in which conjunctival epithelium was used to repair damaged corneal epithelium, was ineffective.
The new concept led to the introduction of a new surgical procedure called “limbal transplantation” in which limbal stem cells are used to repair a damaged or denuded corneal epithelium.
Reference.com/Encyclopedia/Epithelium (772 words)
In biology and dermatology, epithelium is a tissue composed of a layer of cells.
Epithelium lines both the outside (skin) and the inside cavities and lumen of bodies.
A one-cell layer of simple squamous epithelium forms the alveoli of the respiratory membrane, and the endothelium of capillaries, and is a minimal barrier to diffusion.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m