Intercellular space: Difference between revisions
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A space located or occurring between cells is often referred to as an '''intercellular space'''. When the space is passing a cell, or [[cell membrane]] or situated beside or between cells the term '''paracellular space''' is usually used. [[Epithelium|Epithelial cell]]s are packed tightly together, with almost no intercellular spaces and only a small amount of intercellular substance. | A space located or occurring between cells is often referred to as an '''intercellular space'''. When the space is passing a cell, or [[cell membrane]] or situated beside or between cells the term '''paracellular space''' is usually used. [[Epithelium|Epithelial cell]]s are packed tightly together, with almost no intercellular spaces and only a small amount of intercellular substance. | ||
[[Image:Illu epithelium.jpg|thumb|left| | [[Image:Illu epithelium.jpg|thumb|left|200px|Types of epithelium]] | ||
An intercellular space probably can be reduced to that remaining as one membrane physically touches that of its neighboring cell. But, often cells express transmembrane proteins. | An intercellular space probably can be reduced to that remaining as one membrane physically touches that of its neighboring cell. But, often cells express transmembrane proteins. | ||
[[Image:Cell membrane detailed diagram.svg|thumb|left| | [[Image:Cell membrane detailed diagram.svg|thumb|left|400px|Illustration of a cell membrane with transmembrane proteins extending into paracellular space.]] | ||
In order for such transmembrane proteins to function some separation distance between cell membranes must be maintained. | In order for such transmembrane proteins to function some separation distance between cell membranes must be maintained. | ||
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=Intercellular fluid= | =Intercellular fluid= | ||
Intercellular fluid is composed of water and small soluable molecules. Glucose, oxygen and amino acids diffuse into the spaces around the cells from the [[Capillary|capillaries]]. Plasma leaves the capillaries and flows into the spaces between the cells of the tissues to be part of the fluid that surrounds cells | Intercellular fluid is composed of water and small soluable molecules. Glucose, oxygen and amino acids diffuse into the spaces around the cells from the [[Capillary|capillaries]]. Plasma leaves the capillaries and flows into the spaces between the cells of the tissues to be part of the fluid that surrounds those cells. | ||
=[[Capillary|Capillaries]]= | =[[Capillary|Capillaries]]= | ||
'''Capillaries''' measure 5-10 [[micrometre|μm]] in diameter and enable the interchange of [[water]], [[oxygen]], [[carbon dioxide]], and many other [[nutrient]] and [[waste]] [[chemical]] substances between [[blood]] and surrounding [[tissue (biology)|tissue]]s.<ref name=Maton>{{cite book |author= Maton Anthea, Hopkins Jean , McLaughlin Charles William, Johnson Susan, Warner Maryanna Quon, LaHart David, Wright Jill D | title = Human Biology and Health | publisher = Prentice Hall | date = 1993 | location = Englewood Cliffs, New Jersey | pages = | url = | doi = | id = | isbn = 0-13-981176-1}}</ref> True capillaries branch mainly from [[metarteriole]]s and provide exchange between cells and the circulation. The internal diameter of 8 μm forces the red [[blood cell]]s to partially fold into bullet-like shapes and to go into single file in order for them to pass through. Continuous capillaries have a sealed endothelium and only allow small molecules, like water and ions to diffuse. There are those with numerous transport vesicles and [[tight junction]]s and those with few vesicles and tight junctions. Fenestrated capillaries | '''Capillaries''' measure 5-10 [[micrometre|μm]] in diameter and enable the interchange of [[water]], [[oxygen]], [[carbon dioxide]], and many other [[nutrient]] and [[waste]] [[chemical]] substances between [[blood]] and surrounding [[tissue (biology)|tissue]]s.<ref name=Maton>{{cite book |author= Maton Anthea, Hopkins Jean , McLaughlin Charles William, Johnson Susan, Warner Maryanna Quon, LaHart David, Wright Jill D | title = Human Biology and Health | publisher = Prentice Hall | date = 1993 | location = Englewood Cliffs, New Jersey | pages = | url = | doi = | id = | isbn = 0-13-981176-1}}</ref> True capillaries branch mainly from [[metarteriole]]s and provide exchange between cells and the circulation. The internal diameter of 8 μm forces the red [[blood cell]]s to partially fold into bullet-like shapes and to go into single file in order for them to pass through. Continuous capillaries have a sealed endothelium and only allow small molecules, like water and ions to diffuse. There are those with numerous transport vesicles and [[tight junction]]s and those with few vesicles and tight junctions. [[Capillary#Types|Fenestrated capillaries]] have pores in the endothelial cells (60-80 nm in diameter) that are spanned by a diaphragm of radially oriented fibrils and allow small molecules<ref name=Pavelka>{{cite book | title = Functional Ultrastructure: An Atlas of Tissue Biology and Pathology| author = Pavelka, Margit; Jürgen Roth| publisher = Springer | year = 2005 | page = 232}}</ref> and limited amounts of protein to diffuse. Sinusoidal or discontinuous capillaries are special fenestrated capillaries that have larger openings (30-40 μm in diameter) in the endothelium to allow [[red blood cell]s and serum proteins to enter. | ||
=[[Interstitial fluid]]= | =[[Interstitial fluid]]= | ||
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[[Image:Illu capillary microcirculation.jpg|thumb|left]] | [[Image:Illu capillary microcirculation.jpg|thumb|left]] | ||
'''Interstitial fluid''' (or '''tissue fluid''') is a solution which bathes and surrounds the cells of multicellular animals. It is the main component of the [[extracellular fluid]], which also includes [[Blood plasma|plasma]] and [[transcellular fluid]]. The '''interstitial fluid''' is found in the interstitial spaces, also known as the tissue spaces. | '''Interstitial fluid''' (or '''tissue fluid''') is a solution which bathes and surrounds the cells of multicellular animals. It is the main component of the [[extracellular fluid]], which also includes [[Blood plasma|plasma]] and [[transcellular fluid]]. The '''interstitial fluid''' is found in the interstitial spaces, also known as the tissue spaces. [[Interstitial fluid]] consists of a water solvent containing [[amino acid]]s, [[sugar]]s, [[fatty acid]]s, [[coenzyme]]s, [[hormone]]s, [[neurotransmitter]]s, [[salt]]s, as well as waste products from the cells. | ||
=[[Tight junction]]s= | =[[Tight junction]]s= | ||
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=[[Gap junction]]s= | =[[Gap junction]]s= | ||
[[Image:Gap cell junction.svg|thumb|left| | [[Image:Gap cell junction.svg|thumb|left|300px|gap junction]] | ||
In a gap junction the intercellular space is reduced from 25nm to a ~2-4 nm wide paracellular space. | In a gap junction the intercellular space is reduced from 25nm to a ~2-4 nm wide paracellular space. | ||
=[[Desmosome]]s= | |||
[[Image:Cell junction simplified.svg|thumb|400px|Simplified diagram of the main cell junctions, showing changes in intercellular space.]] | |||
[[Image:Desmosome cell junction.svg|thumb|338px|desmosomes]] | |||
[[Image:Desmosome.gif|thumb|220px|right|Cell adhesion in desmosomes]] | |||
The intercellular space is very wide (about 30 nm). | |||
=[[Extracellular|Extracellular space]]= | |||
This space is usually taken to be outside the plasma membrane, and occupied by fluid. The [[stomach]], which for [[human]]s may have the largest breadth between cellular layers, has a diameter in moderate distention of 24-26 cm at its maximum.<ref name=Gray>{{ cite book |author=Gray Henry, Pick Thomas Pickering, Carter Henry Vandyke |title=Anatomy, descriptive and surgical |pages=1000 |edition=14 |publisher=Lea Brothers & Co. |year=1897 |location=Philadelphia |isbn= }}</ref> A [[stomach]] diameter of over 88 cm in women and over 100 cm in men can pose a significant health risk. | |||
[[Extracellular matrix]] includes the interstitial matrix and the [[basement membrane]].<ref name=Kumar>Kumar, Abbas, Fausto; ''Robbins and Cotran: Pathologic Basis of Disease''; Elsevier; 7th ed.</ref> Interstitial matrix is present between various cells (i.e., in the intercellular spaces). Gels of [[polysaccharide]]s and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM.<ref name=Alberts>{{cite book | author = Alberts B, Bray D, Hopin K, Johnson A, Lewis J, Raff M, Roberts K, Walter P | title = Essential cell biology | chapter = Tissues and Cancer | location = New York and London | publisher = Garland Science | year = 2004 | isbn = 0-8153-3481-8}}</ref> | |||
[[Image:Extracellular Matrix.png|thumb|left|350px|Illustration depicting extracellular matrix ([[basement membrane]] and interstitial matrix) in relation to [[epithelium]], [[endothelium]] and [[connective tissue]]]] | |||
Hyaluronic acid in the extracellular space confers upon tissues the ability to resist compression by providing a counteracting [[turgor]] (swelling) force by absorbing alot of water. Hyaluronic acid is thus found in abundance in the ECM of load-bearing joints. It is also a chief component of the interstitial gel. Hyaluronic acid is found on the inner surface of the cell membrane and is translocated out of the cell during biosynthesis.<ref name=Lodish>{{cite book | author = Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J | title = Molecular Cell Biology | edition = 5th | Chapter = Integrating Cells Into Tissues | location = New York | publisher = WH Freeman and Company | pages = 197–234}}</ref> | |||
The epidermal basement membrane zone (BMZ) reveals that it comprises a narrow and sometimes folded interface between the basal keratinocytes and the dermis. At high power, several complex structures are observed within the epidermal BMZ. The epidermal BMZ shows small (< 500 nm), regularly spaced electron dense structures which are the hemidesmosomes. Thin, extracellular, electron-dense lines, parallel to the plasma membrane, subjacent to the outer plaque are visible in one third of HDs and are termed sub-basal dense plates (SBDPs). Anchoring filaments traverse the lamina lucida space and appear to insert into the electron dense zone, the lamina densa. Beneath the lamina densa, loop-structured, cross-banded anchoring fibrils extend more than 300 nm beneath the basement membrane within the papillary dermis. | |||
The [[anterior segment]] is the front third of the eye that includes the structures in front of the [[vitreous humour]]: the cornea, [[iris (anatomy)|iris]], [[ciliary body]], and [[lens (anatomy)|lens]].<ref name="CIO">[http://www.clinica-cotero.es/i/2-1-1.htm "Departments. Anterior segment."] | |||
Cantabrian Institute of Ophthalmology.</ref> Within the anterior segment are two fluid-filled spaces divided by the iris plane: | |||
* 1) the [[anterior chamber]] between the posterior surface of the cornea (i.e. the [[corneal endothelium]]) and the iris. | |||
* 2) the [[posterior chamber]] between the iris and the front face of the vitreous.<ref name="CIO"/> | |||
Aqueous humour fills these spaces within the anterior segment to provide nutrients to the lens and [[corneal endothelium]], and its pressure maintains the convex shape of the cornea.<ref name=Coca-Prados>[http://visionresearch.med.yale.edu/Ophthalmology/people/miguel.html Miguel Coca-Prados, Ph.D.]</ref><ref>Uzzle T. [http://www.svconline.com/mag/avinstall_eye_ear_brain/index.html "The Eye, the Ear, and the Brain."]</ref> | |||
In the Diamond-Bossert model for the production of aqueous humour, active transport occurs in the nonpigmented cilary epithelial cells inducing small osmotic pressure gradients in between the cells. A higher concentration of solutes in the proximal part of the intercellular space generates a flow of water. The concentration diminishes from the proximal part to the distal part, releasing the liquid into the posterior chamber. The primary route for aqueous humour flow is first through the [[posterior chamber]], then the narrow space between the posterior iris and the anterior lens (contributes to small resistance), through the pupil to enter the [[anterior chamber]]. From there, the aqueous humour exits the eye through the [[trabecular meshwork]]. | |||
[[Pus]] is produced from the dead and living [[white blood cells]] which travel into the intercellular spaces around the affected [[cells]]. | |||
=Significant sizes= | |||
The [[diameter]] for [[atom]]s ranges from 62 [[Picometre|pm]] ([[Helium|He]]) to 520 pm ([[Caesium|Cs]]). The smallest [[Molecule#Molecular size|molecule]] is the [[diatomic]] [[hydrogen]] (H<sub>2</sub>), with an overall length of roughly twice the 74 pm (0.74 [[Ångström|Å]]) bond length. Molecules commonly used as building blocks for organic synthesis have a dimension of a few Å to several dozen Å. Single molecules cannot usually be observed by light (as noted above), but small molecules and even the outlines of individual atoms may be traced in some circumstances by use of an [[atomic force microscope]]. Some of the largest molecules are [[macromolecule]]s or supermolecules. | |||
As has been learned by studying the [[nuclear pore complex]], a 10 nm diameter corresponds to an upper mass limit of 70 kDa.<ref name=Melchior>{{ cite journal |author=Melchior F, Gerace L |title=Mechanisms of nuclear protein import |journal=Curr Opin Cell Biol. |volume=7 |issue=3 |month=Jun |year=1995 |pages=310-8 |pmid=7662359 }}</ref> The majority of the non-protein molecules have a [[molecular mass]] of less than 300 [[Atomic mass unit|Da]].<ref name=Goodacre>{{cite journal |author=Goodacre R, Vaidyanathan S, Dunn WB, Harrigan GG, Kell DB |title=Metabolomics by numbers: acquiring and understanding global metabolite data |journal=Trends Biotechnol. |volume=22 |issue=5 |pages=245–52 |year=2004 |month=May |pmid=15109811 |doi=10.1016/j.tibtech.2004.03.007 |url=http://personalpages.manchester.ac.uk/staff/roy.goodacre/learning/metabprof/Goodacre-TibTech2004.pdf|format=PDF}}</ref> | |||
=References= | =References= | ||
{{reflist}} | {{reflist}} | ||
=Acknowledgements= | |||
The content on this page was first contributed by: Henry A. Hoff. | |||
Initial content for this page in some instances came from [http://www.wikipedia.org Wikipedia]. | |||
Revision as of 03:34, 13 May 2009
Editor-In-Chief: Henry A. Hoff
Cells are the fundamental units of all known living organisms. Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 µm; a typical cell mass is 1 ng.
A space located or occurring between cells is often referred to as an intercellular space. When the space is passing a cell, or cell membrane or situated beside or between cells the term paracellular space is usually used. Epithelial cells are packed tightly together, with almost no intercellular spaces and only a small amount of intercellular substance.
An intercellular space probably can be reduced to that remaining as one membrane physically touches that of its neighboring cell. But, often cells express transmembrane proteins.
In order for such transmembrane proteins to function some separation distance between cell membranes must be maintained.
Intercellular fluid
Intercellular fluid is composed of water and small soluable molecules. Glucose, oxygen and amino acids diffuse into the spaces around the cells from the capillaries. Plasma leaves the capillaries and flows into the spaces between the cells of the tissues to be part of the fluid that surrounds those cells.
Capillaries
Capillaries measure 5-10 μm in diameter and enable the interchange of water, oxygen, carbon dioxide, and many other nutrient and waste chemical substances between blood and surrounding tissues.[1] True capillaries branch mainly from metarterioles and provide exchange between cells and the circulation. The internal diameter of 8 μm forces the red blood cells to partially fold into bullet-like shapes and to go into single file in order for them to pass through. Continuous capillaries have a sealed endothelium and only allow small molecules, like water and ions to diffuse. There are those with numerous transport vesicles and tight junctions and those with few vesicles and tight junctions. Fenestrated capillaries have pores in the endothelial cells (60-80 nm in diameter) that are spanned by a diaphragm of radially oriented fibrils and allow small molecules[2] and limited amounts of protein to diffuse. Sinusoidal or discontinuous capillaries are special fenestrated capillaries that have larger openings (30-40 μm in diameter) in the endothelium to allow [[red blood cell]s and serum proteins to enter.
Interstitial fluid
Interstitial fluid (or tissue fluid) is a solution which bathes and surrounds the cells of multicellular animals. It is the main component of the extracellular fluid, which also includes plasma and transcellular fluid. The interstitial fluid is found in the interstitial spaces, also known as the tissue spaces. Interstitial fluid consists of a water solvent containing amino acids, sugars, fatty acids, coenzymes, hormones, neurotransmitters, salts, as well as waste products from the cells.
Tight junctions
The paracellular space in the TEM image appears to be <5 nm.
Gap junctions
In a gap junction the intercellular space is reduced from 25nm to a ~2-4 nm wide paracellular space.
Desmosomes
The intercellular space is very wide (about 30 nm).
Extracellular space
This space is usually taken to be outside the plasma membrane, and occupied by fluid. The stomach, which for humans may have the largest breadth between cellular layers, has a diameter in moderate distention of 24-26 cm at its maximum.[3] A stomach diameter of over 88 cm in women and over 100 cm in men can pose a significant health risk.
Extracellular matrix includes the interstitial matrix and the basement membrane.[4] Interstitial matrix is present between various cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM.[5]
Hyaluronic acid in the extracellular space confers upon tissues the ability to resist compression by providing a counteracting turgor (swelling) force by absorbing alot of water. Hyaluronic acid is thus found in abundance in the ECM of load-bearing joints. It is also a chief component of the interstitial gel. Hyaluronic acid is found on the inner surface of the cell membrane and is translocated out of the cell during biosynthesis.[6]
The epidermal basement membrane zone (BMZ) reveals that it comprises a narrow and sometimes folded interface between the basal keratinocytes and the dermis. At high power, several complex structures are observed within the epidermal BMZ. The epidermal BMZ shows small (< 500 nm), regularly spaced electron dense structures which are the hemidesmosomes. Thin, extracellular, electron-dense lines, parallel to the plasma membrane, subjacent to the outer plaque are visible in one third of HDs and are termed sub-basal dense plates (SBDPs). Anchoring filaments traverse the lamina lucida space and appear to insert into the electron dense zone, the lamina densa. Beneath the lamina densa, loop-structured, cross-banded anchoring fibrils extend more than 300 nm beneath the basement membrane within the papillary dermis.
The anterior segment is the front third of the eye that includes the structures in front of the vitreous humour: the cornea, iris, ciliary body, and lens.[7] Within the anterior segment are two fluid-filled spaces divided by the iris plane:
- 1) the anterior chamber between the posterior surface of the cornea (i.e. the corneal endothelium) and the iris.
- 2) the posterior chamber between the iris and the front face of the vitreous.[7]
Aqueous humour fills these spaces within the anterior segment to provide nutrients to the lens and corneal endothelium, and its pressure maintains the convex shape of the cornea.[8][9]
In the Diamond-Bossert model for the production of aqueous humour, active transport occurs in the nonpigmented cilary epithelial cells inducing small osmotic pressure gradients in between the cells. A higher concentration of solutes in the proximal part of the intercellular space generates a flow of water. The concentration diminishes from the proximal part to the distal part, releasing the liquid into the posterior chamber. The primary route for aqueous humour flow is first through the posterior chamber, then the narrow space between the posterior iris and the anterior lens (contributes to small resistance), through the pupil to enter the anterior chamber. From there, the aqueous humour exits the eye through the trabecular meshwork.
Pus is produced from the dead and living white blood cells which travel into the intercellular spaces around the affected cells.
Significant sizes
The diameter for atoms ranges from 62 pm (He) to 520 pm (Cs). The smallest molecule is the diatomic hydrogen (H2), with an overall length of roughly twice the 74 pm (0.74 Å) bond length. Molecules commonly used as building blocks for organic synthesis have a dimension of a few Å to several dozen Å. Single molecules cannot usually be observed by light (as noted above), but small molecules and even the outlines of individual atoms may be traced in some circumstances by use of an atomic force microscope. Some of the largest molecules are macromolecules or supermolecules.
As has been learned by studying the nuclear pore complex, a 10 nm diameter corresponds to an upper mass limit of 70 kDa.[10] The majority of the non-protein molecules have a molecular mass of less than 300 Da.[11]
References
- ↑ Maton Anthea, Hopkins Jean , McLaughlin Charles William, Johnson Susan, Warner Maryanna Quon, LaHart David, Wright Jill D (1993). Human Biology and Health. Englewood Cliffs, New Jersey: Prentice Hall. ISBN 0-13-981176-1.
- ↑ Pavelka, Margit; Jürgen Roth (2005). Functional Ultrastructure: An Atlas of Tissue Biology and Pathology. Springer. p. 232.
- ↑ Gray Henry, Pick Thomas Pickering, Carter Henry Vandyke (1897). Anatomy, descriptive and surgical (14 ed.). Philadelphia: Lea Brothers & Co. p. 1000.
- ↑ Kumar, Abbas, Fausto; Robbins and Cotran: Pathologic Basis of Disease; Elsevier; 7th ed.
- ↑ Alberts B, Bray D, Hopin K, Johnson A, Lewis J, Raff M, Roberts K, Walter P (2004). "Tissues and Cancer". Essential cell biology. New York and London: Garland Science. ISBN 0-8153-3481-8.
- ↑ Lodish H, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipursky SL, Darnell J. Molecular Cell Biology (5th ed.). New York: WH Freeman and Company. pp. 197–234. Unknown parameter
|Chapter=ignored (|chapter=suggested) (help) - ↑ 7.0 7.1 "Departments. Anterior segment." Cantabrian Institute of Ophthalmology.
- ↑ Miguel Coca-Prados, Ph.D.
- ↑ Uzzle T. "The Eye, the Ear, and the Brain."
- ↑ Melchior F, Gerace L (1995). "Mechanisms of nuclear protein import". Curr Opin Cell Biol. 7 (3): 310–8. PMID 7662359. Unknown parameter
|month=ignored (help) - ↑ Goodacre R, Vaidyanathan S, Dunn WB, Harrigan GG, Kell DB (2004). "Metabolomics by numbers: acquiring and understanding global metabolite data" (PDF). Trends Biotechnol. 22 (5): 245–52. doi:10.1016/j.tibtech.2004.03.007. PMID 15109811. Unknown parameter
|month=ignored (help)
Acknowledgements
The content on this page was first contributed by: Henry A. Hoff.
Initial content for this page in some instances came from Wikipedia.