Array ( [0] => {{short description|Vertebrate organ involved in metabolism}} [1] => {{about|the organ}} [2] => {{Infobox anatomy [3] => | Name = Liver [4] => | Latin = jecur, iecur [5] => | Greek = hepar (ἧπαρ)
root hepat- (ἡπατ-) [6] => | Image = Anatomy Abdomen Tiesworks.jpg [7] => | Caption = The human liver is located in the upper right [[abdomen]] [8] => | Width = 240 [9] => | Image2 = Liver 01 animation1.gif [10] => | Caption2 = Location of human liver (in red) shown on a male body [11] => | Precursor = [[Foregut]] [12] => | System = [[Digestion|Digestive system]] [13] => | Artery = [[Hepatic artery proper|Hepatic artery]] [14] => | Vein = [[Hepatic vein]] and [[hepatic portal vein]] [15] => | Nerve = [[Celiac ganglia]] and [[vagus nerve]]{{cite book| title= Essentials of Human Physiology| first= Thomas M. |last= Nosek| chapter=Section 6/6ch2/s6ch2_30 |chapter-url=http://humanphysiology.tuars.com/program/section6/6ch2/s6ch2_30.htm |archive-url=https://web.archive.org/web/20160324124828/http://humanphysiology.tuars.com/program/section6/6ch2/s6ch2_30.htm|archive-date=2016-03-24}} [16] => | Lymph = [17] => }} [18] => [19] => The '''liver''' is a major [[metabolic]] [[organ (anatomy)|organ]] only found in [[vertebrate]] [[animal]]s, which performs many essential biological functions such as [[detoxification]] of the organism, and the [[Protein biosynthesis|synthesis of proteins]] and biochemicals necessary for [[digestion]] and growth.{{cite journal|last1=Elias|first1=H.|last2=Bengelsdorf|first2=H.|title=The Structure of the Liver in Vertebrates|journal=Cells Tissues Organs|date=1 July 1952|volume=14|issue=4|pages=297–337|doi=10.1159/000140715|pmid=14943381}}{{cite journal |last1=Abdel-Misih |first1=Sherif R.Z. |last2=Bloomston |first2=Mark |title=Liver Anatomy |journal=Surgical Clinics of North America |volume=90 |issue=4 |pages=643–653 |year=2010 |pmid=20637938 |pmc=4038911 |doi=10.1016/j.suc.2010.04.017 }}{{cite web |url=http://www.cancer.ca/en/cancer-information/cancer-type/liver/anatomy-and-physiology/?region=on |title=Anatomy and physiology of the liver – Canadian Cancer Society |publisher=Cancer.ca |access-date=2015-06-26 |archive-url=https://web.archive.org/web/20150626110554/http://www.cancer.ca/en/cancer-information/cancer-type/liver/anatomy-and-physiology/?region=on |archive-date=2015-06-26 |url-status=dead }} In [[human]]s, it is located in the [[quadrants and regions of abdomen|right upper quadrant]] of the [[abdomen]], below the [[thoracic diaphragm|diaphragm]] and mostly shielded by the lower right [[rib cage]]. Its other metabolic roles include [[carbohydrate metabolism]], the production of [[hormone]]s, conversion and storage of nutrients such as [[glucose]] and [[glycogen]], and the decomposition of [[red blood cell]]s. [20] => [21] => The liver is also an [[accessory digestive organ]] that produces [[bile]], an [[alkaline]] fluid containing [[cholesterol]] and [[bile acid]]s, which [[emulsifies]] and aids the [[fatty acid degradation|breakdown of dietary fat]]. The [[gallbladder]], a small hollow pouch that sits just under the right lobe of liver, stores and concentrates the bile produced by the liver, which is later excreted to the [[duodenum]] to help with [[digestion]].{{cite book |first1=Gerard J. |last1=Tortora |first2=Bryan H. |last2=Derrickson |year=2008 |title=Principles of Anatomy and Physiology |edition=12th |publisher=John Wiley & Sons |isbn=978-0-470-08471-7|page=945}} The liver's highly specialized [[biological tissue|tissue]], consisting mostly of [[hepatocyte]]s, regulates a wide variety of high-volume biochemical reactions, including the synthesis and breakdown of small and complex organic molecules, many of which are necessary for normal vital functions.{{cite book | last = Maton | first = Anthea | author2 = Jean Hopkins | author3 = Charles William McLaughlin | author4 = Susan Johnson | author5 = Maryanna Quon Warner | author6 = David LaHart | author7 = Jill D. Wright | title = Human Biology and Health | publisher = Prentice Hall | year = 1993 | location = Englewood Cliffs, New Jersey, USA | isbn = 978-0-13-981176-0 | oclc = 32308337 | url-access = registration | url = https://archive.org/details/humanbiologyheal00scho }} Estimates regarding the organ's total number of functions vary, but is generally cited as being around 500.{{cite book |last1=Zakim |first1=David |last2=Boyer |first2=Thomas D.| year=2002 |title=Hepatology: A Textbook of Liver Disease |edition=4th |isbn =9780721690513}} [22] => [23] => It is not known how to compensate for the absence of liver function in the long term, although [[liver dialysis]] techniques can be used in the short term. [[Artificial organ#Liver|Artificial livers]] have not been developed to promote long-term replacement in the absence of the liver. {{As of|2018}},{{EMedicine|article|1900159|Liver Anatomy}} [[liver transplantation]] is the only option for complete [[liver failure]]. [24] => {{toclimit|3}} [25] => [26] => ==Structure== [27] => [[File:Gray1085.png|thumb|The liver, viewed from above, showing the left and right lobes separated by the [[falciform ligament]]]] [28] => [29] => The liver is a dark reddish brown, wedge-shaped [[organ (anatomy)|organ]] with two [[Lobe (anatomy)|lobes]] of unequal size and shape. A human liver normally weighs approximately {{convert|1.5|kg|lb|abbr=off}}{{cite book |author1=Cotran, Ramzi S. |author2=Kumar, Vinay |author3=Fausto, Nelson |author4=Nelso Fausto |author5=Robbins, Stanley L. |author6=Abbas, Abul K. |title=Robbins and Cotran pathologic basis of disease |url=https://archive.org/details/robbinscotranpat00kuma |url-access=limited |publisher=Elsevier Saunders |location=St. Louis, MO |year=2005 |page=[https://archive.org/details/robbinscotranpat00kuma/page/n929 878] |isbn=978-0-7216-0187-8 |edition=7th }} and has a width of about {{convert|15|cm|in|0|abbr=off}}.{{cite web|url=http://www.mayoclinic.org/diseases-conditions/enlarged-liver/basics/definition/con-20024769|title=Enlarged liver|website=[[Mayo Clinic]]|access-date=2017-03-29|archive-url=https://web.archive.org/web/20170321032952/http://www.mayoclinic.org/diseases-conditions/enlarged-liver/basics/definition/con-20024769|archive-date=2017-03-21|url-status=live}} There is considerable size variation between individuals, with the standard [[reference range]] for men being {{convert|970-1860|g|lb|abbr=out}}{{cite journal|last1=Molina|first1=D. Kimberley|last2=DiMaio|first2=Vincent J.M.|title=Normal Organ Weights in Men|journal=The American Journal of Forensic Medicine and Pathology|volume=33|issue=4|year=2012|pages=368–372|issn=0195-7910|doi=10.1097/PAF.0b013e31823d29ad|pmid=22182984|s2cid=32174574}} and for women {{convert|600-1770|g|lb|abbr=on}}.{{cite journal|last1=Molina|first1=D. Kimberley|last2=DiMaio|first2=Vincent J. M.|title=Normal Organ Weights in Women|journal=The American Journal of Forensic Medicine and Pathology|volume=36|issue=3|year=2015|pages=182–187|issn=0195-7910|doi=10.1097/PAF.0000000000000175|pmid=26108038|s2cid=25319215}} It is both the heaviest internal organ and the largest [[gland]] in the human body. It is located in the right upper quadrant of the [[abdominal cavity]], resting just below the diaphragm, to the right of the stomach, and overlying the [[gallbladder]]. [30] => [31] => The liver is connected to two large [[blood vessel]]s: the [[hepatic artery]] and the [[portal vein]]. The hepatic artery carries oxygen-rich blood from the aorta via the [[celiac trunk]], whereas the portal vein carries blood rich in digested nutrients from the entire [[gastrointestinal tract]] and also from the [[spleen]] and [[pancreas]]. These blood vessels subdivide into small capillaries known as [[liver sinusoid]]s, which then lead to [[Lobules of liver|hepatic lobules]]. [32] => [33] => {{anchor|liver capsule}} [34] => Hepatic lobules are the functional units of the liver. Each lobule is made up of millions of [[hepatic cells]] (hepatocytes), which are the basic metabolic cells. The lobules are held together by a fine, dense, irregular, [[wikt:fibroelastic|fibroelastic]] connective tissue layer extending from the fibrous capsule covering the entire liver known as ''Glisson's capsule'' after British doctor [[Francis Glisson]]. This tissue extends into the structure of the liver by accompanying the blood vessels, ducts, and nerves at the hepatic hilum. The whole surface of the liver, except for the [[bare area of the liver|bare area]], is covered in a [[Serous membrane|serous]] coat derived from the [[peritoneum]], and this firmly adheres to the inner Glisson's capsule. [35] => [36] => ===Gross anatomy=== [37] => Terminology related to the liver often starts in [[List of medical roots, suffixes and prefixes#H|''hepat-'']] from ἡπατο-, from the [[Greek language|Greek]] word for liver.{{cite web | url=http://etymonline.com/index.php?term=hepatic&allowed_in_frame=0 | title=Etymology online hepatic | access-date=December 12, 2013 | archive-url=https://web.archive.org/web/20131215051954/http://etymonline.com/index.php?term=hepatic&allowed_in_frame=0 | archive-date=December 15, 2013 | url-status=dead }} [38] => [39] => ====Lobes==== [40] => {{further|Lobes of liver}} [41] => [[File:Sobo 1906 389.png|thumb|The liver, viewed from below, surface showing four lobes and the impressions]] [42] => [43] => The liver is [[gross anatomy|grossly]] divided into two parts when viewed from above – a right and a left lobe – and four parts when viewed from below (left, right, [[caudate lobe|caudate]], and [[quadrate lobe]]s).{{cite web |url=http://www.liver.co.uk/surgical-anatomy-liver.html |title=Anatomy of the Liver |publisher=Liver.co.uk |access-date=2015-06-26 |archive-url=https://web.archive.org/web/20150627104717/http://www.liver.co.uk/surgical-anatomy-liver.html |archive-date=2015-06-27 |url-status=live }} [44] => [45] => The [[falciform ligament]] makes a superficial division of the liver into a left and right lobe. From below, the two additional lobes are located between the right and left lobes, one in front of the other. A line can be imagined running from the left of the [[vena cava]] and all the way forward to divide the liver and gallbladder into two halves.{{cite book |first1=John F. |last1=Renz |first2=Milan |last2=Kinkhabwala |chapter=Surgical Anatomy of the Liver |chapter-url=https://books.google.com/books?id=XzwHBgAAQBAJ&pg=PA23 |pages=23–39 |year=2014 |editor1-first=Ronald W. |editor1-last=Busuttil |editor2-first=Göran B. |editor2-last=Klintmalm |title=Transplantation of the Liver |publisher=Elsevier |isbn=978-1-4557-5383-3}} This line is called [[Cantlie's line]].{{cite web |url=http://radiopaedia.org/articles/cantlies-line |title=Cantlie's line | Radiology Reference Article |publisher=Radiopaedia.org |access-date=2015-06-26 |archive-url=https://web.archive.org/web/20150627054159/http://radiopaedia.org/articles/cantlies-line |archive-date=2015-06-27 |url-status=live }} [46] => [47] => Other anatomical landmarks include the [[ligamentum venosum]] and the [[round ligament of the liver]], which further divide the left side of the liver in two sections. An important anatomical landmark, the [[porta hepatis]], divides this left portion into four segments, which can be numbered starting at the caudate lobe as I in an anticlockwise manner. From this parietal view, seven segments can be seen, because the eighth segment is only visible in the [[Organ (anatomy)#Viscera|visceral]] view.{{cite book |chapter=Liver resection |chapter-url=https://books.google.com/books?id=oL6d9KuVqLQC&pg=PA900 |pages=900–903 |first1=Erwin |last1=Kuntz |first2=Hans-Dieter |last2=Kuntz |year=2009 |title=Hepatology: Textbook and Atlas |edition=3rd |publisher=Springer |isbn=978-3-540-76839-5}} [48] => [49] => ====Surfaces==== [50] => On the diaphragmatic surface, apart from a triangular bare area where it connects to the diaphragm, the liver is covered by a thin, double-layered membrane, the [[peritoneum]], that helps to reduce friction against other organs.{{cite book |chapter=The Liver Pancreas and Spleen |chapter-url=https://books.google.com/books?id=PVnk5UvDDm4C&pg=PA592 |pages=592–606 |first1=Inderbir |last1=Singh |year=2008 |title=Textbook of Anatomy with Colour Atlas |publisher=Jaypee Brothers |isbn=978-81-8061-833-8 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }} This surface covers the convex shape of the two lobes where it accommodates the shape of the diaphragm. The peritoneum folds back on itself to form the [[falciform ligament]] and the [[right triangular ligament|right]] and [[left triangular ligament]]s.{{cite book |chapter=Liver and Biliary Tract |chapter-url=https://books.google.com/books?id=0qaiox_Vqd4C&pg=PA342 |pages=342–351 |first1=R.M.H. |last1=McMinn |year=2003 |title=Last's Anatomy: Regional and Applied |publisher=Elsevier |isbn=978-0-7295-3752-0}} [51] => [52] => These [[peritoneal ligament]]s are not related to the anatomic ligaments in joints, and the right and left triangular ligaments have no known functional importance, though they serve as surface landmarks. The falciform ligament functions to attach the liver to the [[Anatomical terms of location|posterior]] portion of the [[Anatomical terms of location|anterior]] body wall. [53] => [54] => The visceral surface or inferior surface is uneven and concave. It is covered in peritoneum apart from where it attaches the gallbladder and the porta hepatis. The fossa of gallbladder lies to the right of the quadrate lobe, occupied by the gallbladder with its cystic duct close to the right end of porta hepatis. [55] => [56] => ====Impressions==== [57] => [[File:Gray1087-liver.png|thumb|Impressions of the liver]] [58] => [59] => Several impressions on the surface of the liver accommodate the various adjacent structures and organs. Underneath the right lobe and to the right of the gallbladder fossa are two impressions, one behind the other and separated by a ridge. The one in front is a shallow colic impression, formed by the [[hepatic flexure]] and the one behind is a deeper renal impression accommodating part of the right kidney and part of the [[suprarenal gland]].{{cite book |last1=Skandalakis |first1=Lee J. |last2=Skandalakis |first2=John E. |last3=Skandalakis |first3=Panajiotis N. |title=Surgical Anatomy and Technique |year=2009 |chapter=Liver |doi=10.1007/978-0-387-09515-8_13 |pages=497–531 |isbn=978-0-387-09515-8}} [60] => [61] => The suprarenal impression is a small, triangular, depressed area on the liver. It is located close to the right of the [[Fossa (anatomy)|fossa]], between the bare area and the caudate lobe, and immediately above the renal impression. The greater part of the suprarenal impression is devoid of peritoneum and it lodges the right suprarenal gland.{{sfn|''Dorland's illustrated medical dictionary''|2012|p=925}} [62] => [63] => Medial to the renal impression is a third and slightly marked impression, lying between it and the neck of the gall bladder. This is caused by the descending portion of the duodenum, and is known as the duodenal impression.{{sfn|''Dorland's illustrated medical dictionary''|2012|p=925}} [64] => [65] => The inferior surface of the left lobe of the liver presents behind and to the left of the gastric impression.{{sfn|''Dorland's illustrated medical dictionary''|2012|p=925}} This is moulded over the upper front surface of the stomach, and to the right of this is a rounded eminence, the [[tuber omentale]], which fits into the concavity of the lesser curvature of the stomach and lies in front of the anterior layer of the [[lesser omentum]]. [66] => [67] => ===Microscopic anatomy=== [68] => [[File:Hepatic structure2.svg|thumb|Cells, ducts, and blood vessels]] [69] => [70] => Microscopically, each liver lobe is seen to be made up of [[hepatic lobule]]s. The lobules are roughly hexagonal, and consist of plates of hepatocytes, and sinusoids radiating from a central vein towards an imaginary perimeter of interlobular portal triads.{{cite book |last1=Moore |first1=K |title=Clinically oriented anatomy |date=2018 |isbn=9781496347213 |page=501 |publisher=Wolters Kluwer |edition=Eighth}} The central vein joins to the hepatic vein to carry blood out from the liver. A distinctive component of a lobule is the [[portal triad]], which can be found running along each of the lobule's corners. The portal triad consists of the hepatic artery, the portal vein, and the common bile duct.{{cite book |last1=Moore |first1=K |title=Clinically oriented anatomy |date=2018 |isbn=9781496347213 |page=494 |publisher=Wolters Kluwer |edition=Eighth}} The triad may be seen on a liver ultrasound, as a [[Mickey Mouse sign]] with the portal vein as the head, and the hepatic artery, and the common bile duct as the ears.{{cite web |title=Mickey Mouse sign |url=https://med.emory.edu/departments/emergency-medicine/sections/ultrasound/image-of-the-fortnight/abdominal/mickey_mouse1.html |access-date=31 July 2020}} [71] => [72] => [[Histology]], the study of microscopic anatomy, shows two major types of liver cell: [[parenchyma]]l cells and nonparenchymal cells. About 70–85% of the liver volume is occupied by parenchymal hepatocytes. Nonparenchymal cells constitute 40% of the total number of liver cells but only 6.5% of its volume. The [[liver sinusoid]]s are lined with two types of cell, [[Liver sinusoidal endothelial cell|sinusoidal endothelial cells]], and [[phagocyte|phagocytic]] [[Kupffer cell]]s.{{cite book|last1=Pocock|first1=Gillian|title=Human Physiology|date=2006|publisher=Oxford University Press|isbn=978-0-19-856878-0|page=404|edition=Third}} [[Hepatic stellate cell]]s are nonparenchymal cells found in the [[perisinusoidal space]], between a sinusoid and a hepatocyte.{{cite book |author=Kmieć Z |title=Cooperation of Liver Cells in Health and Disease |chapter=Introduction — Morphology of the Liver Lobule |volume=161 |pages=iii–xiii, 1–151 |year=2001 |pmid=11729749|doi=10.1007/978-3-642-56553-3_1 |series=Advances in Anatomy Embryology and Cell Biology |isbn=978-3-540-41887-0 }} [73] => Additionally, intrahepatic [[lymphocytes]] are often present in the sinusoidal lumen. [74] => {{Clear}} [75] => [76] => 2423 Microscopic Anatomy of Liver.jpg|Microscopic anatomy of the liver [77] => 2104 Three Major Capillary Types.jpg|Types of capillaries–sinusoid on right [78] => 3D Medical Animation liver parts.jpg|alt=3D Medical Animation Still Shot Depicting parts of liver|3D medical animation still shot depicting parts of liver [79] => [80] => [81] => ===Functional anatomy=== [82] => [[File:Hilum of the liver.png|thumb|Hilum of the liver, circled in yellow]] [83] => [84] => The central area or [[hilum (anatomy)|hepatic hilum]], includes the opening known as the porta hepatis which carries the [[common bile duct]] and [[common hepatic artery]], and the opening for the portal vein. The duct, vein, and artery divide into left and right branches, and the areas of the liver supplied by these branches constitute the functional left and right lobes. The functional lobes are separated by the imaginary plane, Cantlie's line, joining the gallbladder fossa to the [[inferior vena cava]]. The plane separates the liver into the true right and left lobes. The middle hepatic vein also demarcates the true right and left lobes. The right lobe is further divided into an [[anterior]] and [[Posterior (anatomy)|posterior]] segment by the right hepatic vein. The left lobe is divided into the [[Medial (anatomy)|medial]] and [[Antero-posteriorly|lateral]] segments by the left hepatic vein. [85] => [86] => The hilum of the liver is described in terms of three ''plates'' that contain the [[bile duct]]s and blood vessels. The contents of the whole plate system are surrounded by a sheath.{{cite journal|last1=Kawarada|first1=Y|last2=Das|first2=BC|last3=Taoka|first3=H|title=Anatomy of the hepatic hilar area: the plate system|journal=Journal of Hepato-Biliary-Pancreatic Surgery|date=2000|volume=7|issue=6|pages=580–586|doi=10.1007/s005340070007|pmid=11180890}} The three plates are the ''hilar plate'', the ''cystic plate'' and the ''umbilical plate'' and the plate system is the site of the many anatomical variations to be found in the liver. [87] => [88] => ===Couinaud classification system=== [89] => {{main|Liver segment}} [90] => [[File:Liver 04 Couinaud classification animation.gif|thumb|Shape of human liver in animation, with eight Couinaud segments labelled]] [91] => [92] => In the widely used [[Claude Couinaud|Couinaud]] system, the functional lobes are further divided into a total of eight subsegments based on a transverse plane through the bifurcation of the main portal vein.{{cite web |url=http://radiopaedia.org/articles/couinaud-classification |title=Couinaud classification | Radiology Reference Article |publisher=Radiopaedia.org |access-date=2015-06-26 |archive-url=https://web.archive.org/web/20150626114315/http://radiopaedia.org/articles/couinaud-classification |archive-date=2015-06-26 |url-status=live }} The caudate lobe is a separate structure that receives blood flow from both the right- and left-sided vascular branches.{{cite web |url=http://dpi.radiology.uiowa.edu/nlm/app/livertoc/liver/liver.html |title=Three-dimensional Anatomy of the Couinaud Liver Segments |access-date=2009-02-17 |archive-url=https://web.archive.org/web/20090209193324/http://dpi.radiology.uiowa.edu/nlm/app/livertoc/liver/liver.html |archive-date=2009-02-09 |url-status=dead }}{{cite journal |last1=Strunk |first1=H. |last2=Stuckmann |first2=G. |last3=Textor |first3=J. |last4=Willinek |first4=W. |title=Limitations and pitfalls of Couinaud's segmentation of the liver in transaxial Imaging |journal=European Radiology |volume=13 |issue=11 |pages=2472–2482 |year=2003 |pmid=12728331 |doi=10.1007/s00330-003-1885-9 |s2cid=34879763 }} The Couinaud classification divides the liver into eight functionally independent liver segments. Each segment has its own vascular inflow, outflow and biliary drainage. In the centre of each segment are branches of the portal vein, hepatic artery, and bile duct. In the periphery of each segment is vascular outflow through the hepatic veins.{{cite web |url=http://www.radiologyassistant.nl/en/p4375bb8dc241d/anatomy-of-the-liver-segments.html |title=The Radiology Assistant : Anatomy of the liver segments |publisher=Radiologyassistant.nl |date=2006-05-07 |access-date=2015-06-26 |archive-url=https://web.archive.org/web/20150626114141/http://www.radiologyassistant.nl/en/p4375bb8dc241d/anatomy-of-the-liver-segments.html |archive-date=2015-06-26 |url-status=live }} The classification system uses the vascular supply in the liver to separate the functional units (numbered I to VIII) with unit 1, the caudate lobe, receiving its supply from both the right and the left branches of the portal vein. It contains one or more hepatic veins which drain directly into the inferior vena cava. The remainder of the units (II to VIII) are numbered in a clockwise fashion: [93] => [94] => === Gene and protein expression === [95] => {{Further |Bioinformatics#Gene and protein expression}} [96] => [97] => About 20,000 protein coding genes are expressed in human cells and 60% of these genes are expressed in a normal, adult liver.{{Cite web|url=https://www.proteinatlas.org/humanproteome/liver|title=The human proteome in liver – The Human Protein Atlas|website=www.proteinatlas.org|access-date=2017-09-21|archive-url=https://web.archive.org/web/20170921004448/http://www.proteinatlas.org/humanproteome/liver|archive-date=2017-09-21|url-status=live}}{{Cite journal|last1=Uhlén|first1=Mathias|last2=Fagerberg|first2=Linn|last3=Hallström|first3=Björn M.|last4=Lindskog|first4=Cecilia|last5=Oksvold|first5=Per|last6=Mardinoglu|first6=Adil|last7=Sivertsson|first7=Åsa|last8=Kampf|first8=Caroline|last9=Sjöstedt|first9=Evelina|date=2015-01-23|title=Tissue-based map of the human proteome|journal=Science|language=en|volume=347|issue=6220|pages=1260419|doi=10.1126/science.1260419|issn=0036-8075|pmid=25613900|s2cid=802377}} Over 400 genes are more specifically expressed in the liver, with some 150 genes highly specific for liver tissue. A large fraction of the corresponding liver-specific proteins are mainly expressed in hepatocytes and secreted into the blood and constitute plasma proteins and [[hepatokines]]. Other liver-specific proteins are certain [[liver enzymes]] such as [[Hydroxyacid oxidase (glycolate oxidase) 1|HAO1]] and [[RDH16]], proteins involved in bile synthesis such as [[BAAT]] and [[SLC27A5]], and transporter proteins involved in the metabolism of drugs, such as [[ABCB11]] and [[GLUT2|SLC2A2]]. Examples of highly liver-specific proteins include [[APOA2|apolipoprotein A II]], coagulation factors [[Prothrombin|F2]] and [[Factor IX|F9]], [[Complement system|complement factor related proteins]], and the [[fibrinogen beta chain]] protein.{{Cite journal|last1=Kampf|first1=Caroline|last2=Mardinoglu|first2=Adil|last3=Fagerberg|first3=Linn|last4=Hallström|first4=Björn M.|last5=Edlund|first5=Karolina|last6=Lundberg|first6=Emma|last7=Pontén|first7=Fredrik|last8=Nielsen|first8=Jens|last9=Uhlen|first9=Mathias|date=2014-07-01|title=The human liver-specific proteome defined by transcriptomics and antibody-based profiling|journal=The FASEB Journal|language=en|volume=28|issue=7|pages=2901–2914|doi=10.1096/fj.14-250555|doi-access=free |issn=0892-6638|pmid=24648543|s2cid=5297255}} [98] => [99] => ==Development== [100] => [[File:CT Scan Thorax Liver.jpg|thumb|CT scan showing an adult liver in the axial plane]] [101] => [102] => [[Organogenesis]], the development of the organs, takes place from the third to the eighth week during [[human embryogenesis|embryogenesis]]. The origins of the liver lie in both the ventral portion of the [[foregut]] [[endoderm]] (endoderm being one of the three embryonic [[germ layer]]s) and the constituents of the adjacent [[septum transversum]] [[mesenchyme]]. In the human [[embryo]], the [[hepatic diverticulum]] is the tube of endoderm that extends out from the foregut into the surrounding mesenchyme. The mesenchyme of septum transversum induces this endoderm to proliferate, to branch, and to form the glandular epithelium of the liver. A portion of the hepatic diverticulum (that region closest to the digestive tube) continues to function as the [[Biliary tract|drainage duct]] of the liver, and a branch from this duct produces the gallbladder.{{cite book | last = Gilbert SF | title = Developmental Biology | edition = 6th | publisher = Sinauer Associates | year = 2000 | location = Sunderland (MA) | url = https://www.ncbi.nlm.nih.gov/books/NBK10107/#A3752 | access-date = 2017-09-04 | archive-url = https://web.archive.org/web/20171218061140/https://www.ncbi.nlm.nih.gov/books/NBK10107/#A3752 | archive-date = 2017-12-18 | url-status = live }} Besides signals from the septum transversum mesenchyme, [[fibroblast growth factor]] from the [[Heart development|developing heart]] also contributes to hepatic competence, along with [[retinoic acid]] emanating from the [[lateral plate mesoderm]]. The hepatic endodermal cells undergo a morphological transition from columnar to pseudostratified resulting in thickening into the early [[Hepatic diverticulum|liver bud]]. Their expansion forms a population of the bipotential hepatoblasts.{{cite journal |vauthors=Lade AG, Monga SP | title = Beta-catenin signaling in hepatic development and progenitors: which way does the WNT blow? | journal = Dev Dyn | volume = 240 | issue = 3 | pages = 486–500 | year = 2011 | pmid = 21337461 | pmc = 4444432 | doi = 10.1002/dvdy.22522}} Hepatic stellate cells are derived from mesenchyme.{{cite journal |vauthors=Berg T, DeLanghe S, Al Alam D, Utley S, Estrada J, Wang KS | title = β-catenin regulates mesenchymal progenitor cell differentiation during hepatogenesis | journal = J Surg Res | volume = 164| issue = 2 | pages = 276–285 | year = 2010 | pmid = 20381814 | doi = 10.1016/j.jss.2009.10.033 | pmc = 2904820}} [103] => [104] => After migration of hepatoblasts into the septum transversum mesenchyme, the hepatic architecture begins to be established, with liver sinusoids and bile canaliculi appearing. The liver bud separates into the lobes. The left [[umbilical vein]] becomes the [[ductus venosus]] and the right [[vitelline vein]] becomes the portal vein. The expanding liver bud is colonized by [[Hematopoietic stem cell|hematopoietic cells]]. The bipotential hepatoblasts begin differentiating into [[Cholangiocyte|biliary epithelial cells]] and hepatocytes. The biliary epithelial cells differentiate from hepatoblasts around portal veins, first producing a monolayer, and then a bilayer of cuboidal cells. In ductal plate, focal dilations emerge at points in the bilayer, become surrounded by portal mesenchyme, and undergo tubulogenesis into intrahepatic bile ducts. Hepatoblasts not adjacent to portal veins instead differentiate into hepatocytes and arrange into cords lined by sinusoidal epithelial cells and bile canaliculi. Once hepatoblasts are specified into hepatocytes and undergo further expansion, they begin acquiring the functions of a mature hepatocyte, and eventually mature hepatocytes appear as highly polarized epithelial cells with abundant [[glycogen]] accumulation. In the adult liver, hepatocytes are not equivalent, with position along the portocentrovenular axis within a liver lobule dictating expression of metabolic genes involved in drug metabolism, [[carbohydrate metabolism]], ammonia detoxification, and bile production and secretion. [[Wnt signaling pathway|WNT/β-catenin]] has now been identified to be playing a key role in this phenomenon. [105] => [106] => [[File:Ultrasound liver right lobe and right kidney.jpg|thumb|Adult ultrasound showing the right lobe of the liver and right kidney]] [107] => [108] => At birth, the liver comprises roughly 4% of body weight and weighs on average about {{convert|120|g|oz|0|abbr=on}}. Over the course of further development, it will increase to {{convert|1.4|–|1.6|kg|lb|1|abbr=on}} but will only take up 2.5–3.5% of body weight.{{cite book | title=Anatomy a Regional Atlas of the Human Body | url=https://archive.org/details/anatomyregionala00clem_455 | url-access=limited | publisher=Lippincott Williams & Wilkins | author=Clemente, Carmin D. | year=2011 | location=Philadelphia | page=[https://archive.org/details/anatomyregionala00clem_455/page/n266 243] | isbn=978-1-58255-889-9}} [109] => [110] => Hepatosomatic index (HSI) is the ratio of liver weight to body weight.{{cite journal |last1=Egerton |first1=S. |last2=Wan |first2=A. |last3=Murphy |first3=K. |last4=Collins |first4=F. |last5=Ahern |first5=G. |last6=Sugrue |first6=I. |last7=Busca |first7=K. |last8=Egan |first8=F. |last9=Muller |first9=N. |last10=Whooley |first10=J. |last11=McGinnity |first11=P. |last12=Culloty |first12=S. |last13=Ross |first13=R. P. |last14=Stanton |first14=C. |title=Replacing fishmeal with plant protein in Atlantic salmon (Salmo salar) diets by supplementation with fish protein hydrolysate |journal=Scientific Reports |date=6 March 2020 |volume=10 |issue=1 |page=4194 |doi=10.1038/s41598-020-60325-7 |pmid=32144276 |pmc=7060232 |bibcode=2020NatSR..10.4194E }} [111] => [112] => ===Fetal blood supply=== [113] => In the growing fetus, a major source of blood to the liver is the umbilical vein, which supplies nutrients to the growing fetus. The umbilical vein enters the abdomen at the umbilicus and passes upward along the free margin of the falciform ligament of the liver to the inferior surface of the liver. There, it joins with the left branch of the portal vein. The ductus venosus carries blood from the left portal vein to the left hepatic vein and then to the inferior vena cava, allowing placental blood to bypass the liver. In the fetus, the liver does not perform the normal digestive processes and filtration of the infant liver because nutrients are received directly from the mother via the [[placenta]]. The fetal liver releases some blood stem cells that migrate to the fetal [[thymus]], creating the {{Nowrap|[[T cell]]s}} (or T lymphocytes). After birth, the formation of blood stem cells shifts to the red [[bone marrow]]. After 2–5 days, the umbilical vein and ductus venosus are obliterated; the former becomes the [[round ligament of liver]] and the latter becomes the ligamentum venosum. In the [[medical disorder|disorders]] of [[cirrhosis]] and [[portal hypertension]], the umbilical vein can open up again. [114] => [115] => Unlike eutherian mammals, in marsupials the liver remains haematopoietic well after birth.{{cite journal |last1=Old |first1=J.M. |last2=Deane |first2=E.M. |title=Development of the immune system and immunological protection in marsupial pouch young |journal=Developmental & Comparative Immunology |date=July 2000 |volume=24 |issue=5 |pages=445–454 |doi=10.1016/S0145-305X(00)00008-2 |pmid=10785270 }}{{cite journal |last1=Old |first1=Julie M. |title=Haematopoiesis in Marsupials |journal=Developmental & Comparative Immunology |date=May 2016 |volume=58 |pages=40–46 |doi=10.1016/j.dci.2015.11.009 |pmid=26592963 }}{{cite journal |last1=Old |first1=J.M |last2=Selwood |first2=L |last3=Deane |first3=E.M |title=A developmental investigation of the liver, bone marrow and spleen of the stripe-faced dunnart (Sminthopsis macroura) |journal=Developmental & Comparative Immunology |date=April 2004 |volume=28 |issue=4 |pages=347–355 |doi=10.1016/j.dci.2003.08.004 |pmid=14698220 }}{{cite journal |last1=Old |first1=J. M. |last2=Deane |first2=E. M. |title=The lymphoid and immunohaematopoietic tissues of the embryonic brushtail possum (Trichosurus vulpecula) |journal=Anatomy and Embryology |date=February 2003 |volume=206 |issue=3 |pages=193–197 |doi=10.1007/s00429-002-0285-2 |pmid=12592570 }} [116] => [117] => ==Functions== [118] => The various functions of the liver are carried out by the liver cells or hepatocytes. The liver is thought to be responsible for up to 500 separate functions, usually in combination with other systems and organs. Currently, no [[artificial organ]] or device is capable of reproducing all the functions of the liver. Some functions can be carried out by [[liver dialysis]], an experimental treatment for [[liver failure]]. The liver also accounts for about 20% of resting total body oxygen consumption. [119] => [120] => ===Blood supply=== [121] => The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers around 75% of the liver's blood supply and carries [[venous blood]] drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow. Oxygen is provided from both sources; about half of the liver's oxygen demand is met by the hepatic portal vein, and half is met by the hepatic arteries.{{cite book |author1=Shneider, Benjamin L. |author2=Sherman, Philip M. |title=Pediatric Gastrointestinal Disease |publisher=PMPH-USA|location=Connecticut |year=2008 |page=751 |isbn=978-1-55009-364-3 }} The hepatic artery also has both alpha- and beta-adrenergic receptors; therefore, flow through the artery is controlled, in part, by the splanchnic nerves of the autonomic nervous system. [122] => [123] => Blood flows through the liver sinusoids and empties into the central vein of each lobule. The [[Central veins of liver|central veins]] coalesce into hepatic veins, which leave the liver and drain into the inferior vena cava.{{cite book|title=Human Anatomy & Physiology + New Masteringa&p With Pearson Etext|date=2012|publisher=Benjamin-Cummings Pub Co|isbn=9780321852120|page=881}} [124] => [125] => {{gallery|mode=packed [126] => |Liver veins.jpg|The liver and its veins [127] => |Liver vascular anatomy.svg|Diagram of liver, lobule, and portal tract and their inter-relations [128] => }} [129] => [130] => ===Biliary flow=== [131] => {{Main |Enterohepatic circulation}} [132] => [[File:Diagram showing the position of the perihilar bile ducts CRUK 357.svg|thumb|Biliary tract]] [133] => [134] => The [[biliary tract]] is derived from the branches of the bile ducts. The biliary tract, also known as the biliary tree, is the path by which bile is secreted by the liver then transported to the first part of the small intestine, the [[duodenum]]. The bile produced in the liver is collected in [[bile canaliculi]], small grooves between the faces of adjacent hepatocytes. The canaliculi radiate to the edge of the liver lobule, where they merge to form bile ducts. Within the liver, these ducts are termed intrahepatic bile ducts, and once they exit the liver, they are considered extrahepatic. The intrahepatic ducts eventually drain into the right and left hepatic ducts, which exit the liver at the [[Porta hepatis|transverse fissure]], and merge to form the common hepatic duct. The [[cystic duct]] from the gallbladder joins with the common hepatic duct to form the common bile duct. The biliary system and connective tissue is supplied by the hepatic artery alone. [135] => [136] => Bile either drains directly into the duodenum via the common bile duct, or is temporarily stored in the gallbladder via the cystic duct. The common bile duct and the pancreatic duct enter the second part of the duodenum together at the hepatopancreatic ampulla, also known as the [[ampulla of Vater]]. [137] => [138] => ===Metabolism=== [139] => {{Further|Proteins produced and secreted by the liver}} [140] => [141] => The liver plays a major role in carbohydrate, protein, amino acid, and lipid metabolism. [142] => [143] => ====Carbohydrate metabolism==== [144] => The liver performs several roles in carbohydrate metabolism. [145] => * The liver synthesizes and stores around 100g of glycogen via [[glycogenesis]], the formation of glycogen from [[glucose]]. [146] => * When needed, the liver releases glucose into the blood by performing [[glycogenolysis]], the breakdown of glycogen into glucose.{{cite book|title=Human Anatomy & Physiology + New Masteringa&p With Pearson Etext|date=2012|publisher=Benjamin-Cummings Pub Co|isbn=9780321852120|page=939}} [147] => * The liver is also responsible for [[gluconeogenesis]], which is the synthesis of glucose from certain [[amino acid]]s, [[lactic acid|lactate]], or [[glycerol]]. Adipose and liver cells produce glycerol by [[lipolysis|breakdown of fat]], which the liver uses for gluconeogenesis. [148] => * Liver also does '''glyconeogenesis''' which is synthesis of glycogen from [[lactic acid]].{{cite book |doi=10.1016/B0-12-227055-X/00563-0 |chapter=Glycogen |title=Encyclopedia of Food Sciences and Nutrition |date=2003 |last1=Rocha Leão |first1=M.H.M. |pages=2930–2937 |isbn=978-0-12-227055-0 }} [149] => [150] => ====Protein metabolism==== [151] => The liver is responsible for the mainstay of protein [[metabolism]], synthesis as well as degradation. All [[plasma proteins]] except [[Gamma globulin|Gamma-globulins]] are synthesised in the liver.{{Cite journal|last1=Miller|first1=L. L.|last2=Bale|first2=W. F.|date=February 1954|title=Synthesis of all plasma protein fractions except gamma globulins by the liver; the use of zone electrophoresis and lysine-epsilon-C14 to define the plasma proteins synthesized by the isolated perfused liver|journal=The Journal of Experimental Medicine|volume=99|issue=2|pages=125–132|doi=10.1084/jem.99.2.125|issn=0022-1007|pmc=2180344|pmid=13130789}} It is also responsible for a large part of [[amino acid synthesis]]. The liver plays a role in the production of clotting factors, as well as [[red blood cell]] production. Some of the proteins synthesized by the liver include [[coagulation factors]] [[fibrinogen|I]] (fibrinogen), [[thrombin|II]] (prothrombin), [[factor V|V]], [[factor VII|VII]], [[factor VIII|VIII]], [[factor IX|IX]], [[factor X|X]], [[factor XI|XI]], [[factor XII|XII]], [[factor XIII|XIII]], as well as [[protein C]], [[protein S]] and [[antithrombin]]. The liver is a major site of production for [[thrombopoietin]], a [[glycoprotein]] hormone that regulates the production of [[platelet]]s by the bone marrow.{{cite journal |last1=Jelkmann |first1=Wolfgang |title=The role of the liver in the production of thrombopoietin compared with erythropoietin |journal=European Journal of Gastroenterology & Hepatology |volume=13 |issue=7 |pages=791–801 |year=2001 |pmid=11474308 |doi=10.1097/00042737-200107000-00006}} [152] => [153] => ====Lipid metabolism==== [154] => The liver plays several roles in [[lipid]] metabolism: it performs [[cholesterol]] synthesis, [[lipogenesis]], and the production of [[triglyceride]]s, and a bulk of the body's lipoproteins are synthesized in the liver. The liver plays a key role in digestion, as it produces and excretes [[bile]] (a yellowish liquid) required for emulsifying fats and help the absorption of vitamin K from the diet. Some of the bile drains directly into the duodenum, and some is stored in the gallbladder. The liver produces [[insulin-like growth factor 1]], a [[polypeptide]] [[protein]] hormone that plays an important role in childhood growth and continues to have [[anabolism|anabolic effects]] in adults. [155] => [156] => ===Breakdown=== [157] => The liver is responsible for the breakdown of [[insulin]] and other [[hormone]]s. The liver breaks down [[bilirubin]] via [[glucuronidation]], facilitating its excretion into bile. [158] => The liver is responsible for the breakdown and excretion of many waste products. It plays a key role in breaking down or modifying toxic substances (e.g., [[methylation]]) and most medicinal products in a process called [[drug metabolism]]. This sometimes results in [[toxication]], when the metabolite is more toxic than its precursor. Preferably, the toxins are [[Xenobiotic conjugation|conjugated]] to avail excretion in bile or urine. The liver converts [[ammonia]] into [[urea]] as part of the [[urea cycle|ornithine cycle]] or the urea cycle, and the urea is excreted in the urine.{{cite book|title=Human Anatomy & Physiology + New Masteringa&p With Pearson Etext|date=2012|publisher=Benjamin-Cummings Pub Co|isbn=9780321852120}} [159] => [160] => === Blood reservoir === [161] => Because the liver is an expandable organ, large quantities of blood can be stored in its blood vessels. Its normal blood volume, including both that in the hepatic veins and that in the hepatic sinuses, is about 450 milliliters, or almost 10 percent of the body's total blood volume. When high pressure in the right atrium causes backpressure in the liver, the liver expands, and 0.5 to 1 liter of extra blood is occasionally stored in the hepatic veins and sinuses. This occurs especially in cardiac failure with peripheral congestion. Thus, in effect, the liver is a large, expandable, venous organ capable of acting as a valuable blood reservoir in times of excess blood volume and capable of supplying extra blood in times of diminished blood volume.{{cite journal |last1=Lautt |first1=WW |last2=Greenway |first2=CV |title=Hepatic venous compliance and role of liver as a blood reservoir |journal=American Journal of Physiology-Legacy Content |date=August 1976 |volume=231 |issue=2 |pages=292–295 |doi=10.1152/ajplegacy.1976.231.2.292 |pmid=961879 }} [162] => [163] => === Lymph production === [164] => Because the pores in the hepatic sinusoids are very permeable and allow ready passage of both fluid and proteins into the [[perisinusoidal space]], the [[lymph]] draining from the liver usually has a protein concentration of about 6 g/dl, which is only slightly less than the protein concentration of plasma. [165] => Also, the high permeability of the liver sinusoid epithelium allows large quantities of lymph to form. Therefore, about half of all the lymph formed in the body under resting conditions arises in the liver. [166] => [167] => ===Other=== [168] => * The liver stores a multitude of substances, including [[vitamin A]] (1–2 years' supply), [[vitamin D]] (1–4 months' supply),{{cite web |url=https://www.lecturio.com/concepts/liver|title=Liver|website=The Lecturio Medical Concept Library |date=9 September 2020|access-date=2021-06-23}} [[vitamin B12|vitamin B12]] (3–5 years' supply),{{cite web|title=If a person stops consuming the vitamin, the body's stores of this vitamin usually take about 3 to 5 years to exhaust|url=https://www.merckmanuals.com/home/disorders-of-nutrition/vitamins/vitamin-b12-deficiency|access-date=2022-08-21}} [[vitamin K]], [[vitamin E]], [[iron]], [[copper]], [[zinc]], [[cobalt]], [[molybdenum]], etc. [169] => *[[Haemopoiesis]] - The formation of blood cells is called haemopoiesis. In embryonic stage RBC and WBC are formed by liver. In the first trimester fetus, the liver is the main site of red blood cell production. By the 32nd week of [[gestation]], the [[bone marrow]] has almost completely taken over that task.{{cite journal |last1=Timens |first1=Wim |last2=Kamps |first2=Willem A. |last3=Rozeboom-Uiterwijk |first3=Thea |last4=Poppema |first4=Sibrand |title=Haemopoiesis in human fetal and embryonic liver: Immunohistochemical determination in B5-fixed paraffin-embedded tissues |journal=Virchows Archiv a Pathological Anatomy and Histopathology |date=September 1990 |volume=416 |issue=5 |pages=429–436 |doi=10.1007/BF01605149 |pmid=2107630 |s2cid=10436627 }} [170] => *The liver helps in the purification of blood. The [[Kupffer cell]]s of liver are [[Phagocyte|phagocytic cells]], helps in phagocytosis of dead blood cells and bacteria from the blood.{{Cite journal|last1=Nguyen-Lefebvre|first1=Anh Thu|last2=Horuzsko|first2=Anatolij|date=2015|title=Kupffer Cell Metabolism and Function|journal=Journal of Enzymology and Metabolism|volume=1|issue=1|pmc=4771376|pmid=26937490}} [171] => * The liver is responsible for immunological effects – the [[mononuclear phagocyte system]] of the liver contains many immunologically active cells, acting as a 'sieve' for antigens carried to it via the [[Hepatic portal system|portal system]]. [172] => * The liver produces [[albumin]], the most abundant protein in [[Blood plasma|blood serum]]. It is essential in the maintenance of [[oncotic pressure]], and acts as a transport for [[fatty acid]]s and [[steroid hormone]]s. [173] => * The liver synthesizes [[angiotensinogen]], a hormone that is responsible for raising the [[blood pressure]] when activated by [[renin]], an enzyme that is released when the [[juxtaglomerular apparatus|kidney]] senses [[Hypotension|low blood pressure]]. [174] => * The liver produces the enzyme [[catalase]] to break down [[hydrogen peroxide]], a toxic [[Oxidizing agent|oxidising agent]], into water and oxygen. [175] => [176] => ==Clinical significance== [177] => [178] => ===Disease=== [179] => {{Main|Liver disease}} [180] => [[File:Big Liver Tumor.JPG|thumb|Left lobe liver tumor]] [181] => [182] => The liver is a vital organ and supports almost every other organ in the body. Because of its strategic location and multidimensional functions, the liver is prone to many diseases.[http://digestive.niddk.nih.gov/ddiseases/pubs/cirrhosis/ Cirrhosis Overview] {{Webarchive|url=https://web.archive.org/web/20111030040354/http://digestive.niddk.nih.gov/ddiseases/pubs/cirrhosis/ |date=2011-10-30 }} National Digestive Diseases Information Clearinghouse. Retrieved 2010-01-22 The bare area of the liver is a site that is vulnerable to the passing of infection from the abdominal cavity to the [[thoracic cavity]]. Liver diseases may be diagnosed by [[liver function tests]]–blood tests that can identify various markers. For example, [[Acute-phase protein|acute-phase reactants]] are produced by the liver in response to injury or inflammation. [183] => [184] => The most common chronic liver disease is [[nonalcoholic fatty liver disease]], which affects an estimated one-third of the world population.{{cite journal |last1=Younossi |first1=Zobair M. |last2=Golabi |first2=Pegah |last3=Paik |first3=James M. |last4=Henry |first4=Austin |last5=Van Dongen |first5=Catherine |last6=Henry |first6=Linda |title=The global epidemiology of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH): a systematic review |journal=Hepatology |date=1 April 2023 |volume=77 |issue=4 |pages=1335–1347 |doi=10.1097/HEP.0000000000000004 |pmid=36626630 |pmc=10026948 |issn=1527-3350}} [185] => [186] => [[Hepatitis]] is a common condition of inflammation of the liver. The most usual cause of this is [[viral hepatitis|viral]], and the most common of these infections are [[hepatitis A]], [[hepatitis B|B]], [[hepatitis C|C]], [[hepatitis D|D]], and [[hepatitis E|E]]. Some of these infections are [[sexually transmitted diseases|sexually transmitted]]. Inflammation can also be caused by other viruses in the family [[Herpesviridae]] such as the [[herpes simplex virus]]. Chronic (rather than acute) infection with hepatitis B virus or hepatitis C virus is the main cause of [[liver cancer]].[http://www.webmd.com/hepatitis/ Hepatitis A, B, and C Center: Symptoms, Causes, Tests, Transmission, and Treatments] {{Webarchive|url=https://web.archive.org/web/20160131173401/http://www.webmd.com/hepatitis/ |date=2016-01-31 }}. Webmd.com (2005-08-19). Retrieved on 2016-05-10. Globally, about 248 million individuals are chronically infected with hepatitis B (with 843,724 in the U.S.),{{cite journal |vauthors=Schweitzer A, Horn J, Mikolajczyk RT, Krause G, Ott JJ |title=Estimations of worldwide prevalence of chronic hepatitis B virus infection: a systematic review of data published between 1965 and 2013 |journal=Lancet |volume=386 |issue=10003 |pages=1546–1555 |year=2015 |pmid=26231459 |doi=10.1016/S0140-6736(15)61412-X |s2cid=41847645 }} and 142 million are chronically infected with hepatitis C{{cite journal |title=Global, regional, and national incidence, prevalence, and years lived with disability for 310 diseases and injuries, 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015 |journal=Lancet |volume=388 |issue=10053 |pages=1545–1602 |year=2016 |pmid=27733282 |pmc=5055577 |doi=10.1016/S0140-6736(16)31678-6 |last1=Vos |first1=Theo |last2=Allen |first2=Christine |last3=Arora |first3=Megha |last4=Barber |first4=Ryan M. |last5=Bhutta |first5=Zulfiqar A. |last6=Brown |first6=Alexandria |last7=Carter |first7=Austin |last8=Casey |first8=Daniel C. |last9=Charlson |first9=Fiona J. |last10=Chen |first10=Alan Z. |last11=Coggeshall |first11=Megan |last12=Cornaby |first12=Leslie |last13=Dandona |first13=Lalit |last14=Dicker |first14=Daniel J. |last15=Dilegge |first15=Tina |last16=Erskine |first16=Holly E. |last17=Ferrari |first17=Alize J. |last18=Fitzmaurice |first18=Christina |last19=Fleming |first19=Tom |last20=Forouzanfar |first20=Mohammad H. |last21=Fullman |first21=Nancy |last22=Gething |first22=Peter W. |last23=Goldberg |first23=Ellen M. |last24=Graetz |first24=Nicholas |last25=Haagsma |first25=Juanita A. |last26=Hay |first26=Simon I. |last27=Johnson |first27=Catherine O. |last28=Kassebaum |first28=Nicholas J. |last29=Kawashima |first29=Toana |last30=Kemmer |first30=Laura |display-authors=29 }} (with 2.7 million in the U.S.).{{cite web |url=https://www.hepatitisc.uw.edu/pdf/screening-diagnosis/epidemiology-us/core-concept/all |title=www.hepatitisc.uw.edu |archive-url=https://web.archive.org/web/20170825131002/http://www.hepatitisc.uw.edu/pdf/screening-diagnosis/epidemiology-us/core-concept/all |archive-date=2017-08-25 |url-status=live }} Globally there are about 114 million and 20 million cases of hepatitis A and hepatitis E{{cite web |url=https://www.who.int/mediacentre/factsheets/fs280/en/ |title=WHO | Hepatitis E |archive-url=https://web.archive.org/web/20160312074914/http://www.who.int/mediacentre/factsheets/fs280/en/ |archive-date=2016-03-12 |url-status=live }} respectively, but these generally resolve and do not become chronic. Hepatitis D virus is a "satellite" of hepatitis B virus (it can only infect in the presence of hepatitis B), and co-infects nearly 20 million people with hepatitis B, globally.{{cite book |doi=10.1007/3-540-29802-9_8 |chapter=Hepatitis Delta Virus Genetic Variability: From Genotypes I, II, III to Eight Major Clades? |title=Hepatitis Delta Virus |series=Current Topics in Microbiology and Immunology |date=2006 |last1=Dény |first1=P. |volume=307 |pages=151–171 |pmid=16903225 |isbn=978-3-540-29801-4 }} [187] => [188] => [[Hepatic encephalopathy]] is caused by an accumulation of toxins in the bloodstream that are normally removed by the liver. This condition can result in coma and can prove fatal. [[Budd–Chiari syndrome]] is a condition caused by [[Vascular occlusion|blockage]] of the [[hepatic veins]] (including [[thrombosis]]) that drain the liver. It presents with the classical triad of abdominal pain, [[ascites]] and [[liver enlargement]].{{cite journal|vauthors=Rajani R, Melin T, Björnsson E, Broomé U, Sangfelt P, Danielsson A, Gustavsson A, Grip O, Svensson H, Lööf L, Wallerstedt S, Almer SH|date=Feb 2009|title=Budd-Chiari syndrome in Sweden: epidemiology, clinical characteristics and survival – an 18-year experience|journal=Liver International|volume=29|issue=2|pages=253–259|doi=10.1111/j.1478-3231.2008.01838.x|pmid=18694401|s2cid=36353033}} Many diseases of the liver are accompanied by [[jaundice]] caused by increased levels of [[bilirubin]] in the system. The bilirubin results from the breakup of the [[hemoglobin]] of dead red blood cells; normally, the liver removes bilirubin from the blood and excretes it through bile. [189] => [190] => Other disorders caused by excessive alcohol consumption are grouped under [[alcoholic liver disease]]s and these include [[alcoholic hepatitis]], [[fatty liver]], and [[cirrhosis]]. Factors contributing to the development of alcoholic liver diseases are not only the quantity and frequency of alcohol consumption, but can also include gender, genetics, and liver insult. Liver damage can also be [[hepatotoxicity|caused by drugs]], particularly [[paracetamol]] and drugs used to treat cancer. A rupture of the liver can be caused by a [[liver shot]] used in combat sports. [191] => [192] => [[Primary biliary cholangitis]] is an [[autoimmune disease]] of the liver.{{cite journal|last=Hirschfield|first=GM|author2=Gershwin, ME|title=The immunobiology and pathophysiology of primary biliary cirrhosis|journal=Annual Review of Pathology|date=Jan 24, 2013|volume=8|pages=303–330|pmid=23347352|doi=10.1146/annurev-pathol-020712-164014}}{{cite book |first=Henryk |last=Dancygier |title=Clinical Hepatology Principles and Practice of|url=https://books.google.com/books?id=lrPX8C4p90QC&pg=PA895 |access-date=29 June 2010 |year=2010 |publisher=Springer |isbn=978-3-642-04509-7 |pages=895–}} It is marked by slow progressive destruction of the small [[bile duct]]s of the liver, with the intralobular ducts ([[Canals of Hering]]) affected early in the disease.{{cite journal |last1=Saxena |first1=Romil |last2=Theise |first2=Neil |title=Canals of Hering: Recent Insights and Current Knowledge |journal=Seminars in Liver Disease |volume=24 |issue=1 |pages=43–48 |year=2004 |pmid=15085485 |doi=10.1055/s-2004-823100 |s2cid=260317971 }} When these ducts are damaged, bile and other toxins build up in the liver ([[cholestasis]]) and over time damages the liver tissue in combination with ongoing immune related damage. This can lead to scarring ([[fibrosis]]) and [[cirrhosis]]. Cirrhosis increases the resistance to blood flow in the liver, and can result in [[portal hypertension]]. [[Portacaval anastomosis|Congested anastomoses]] between the [[portal venous system]] and the systemic circulation, can be a subsequent condition. [193] => [194] => There are also many pediatric liver diseases, including [[biliary atresia]], [[alpha-1 antitrypsin deficiency]], [[alagille syndrome]], [[progressive familial intrahepatic cholestasis]], [[Langerhans cell histiocytosis]] and [[cavernous liver haemangioma|hepatic hemangioma]] a [[benign tumour]] the most common type of liver tumour, thought to be congenital. A genetic disorder causing multiple cysts to form in the liver tissue, usually in later life, and usually asymptomatic, is [[polycystic liver disease]]. Diseases that interfere with liver function will lead to derangement of these processes. However, the liver has a great capacity to [[regeneration (biology)|regenerate]] and has a large reserve capacity. In most cases, the liver only produces symptoms after extensive damage. [195] => [196] => [[Hepatomegaly]] refers to an enlarged liver and can be due to many causes. It can be [[palpated]] in a [[liver span]] measurement. [197] => [198] => ===Symptoms=== [199] => The classic symptoms of liver damage include the following: [200] => * Pale stools occur when [[stercobilin]], a brown pigment, is absent from the stool. Stercobilin is derived from bilirubin metabolites produced in the liver. [201] => * Dark urine occurs when bilirubin mixes with urine [202] => * Jaundice (yellow skin and/or whites of the eyes) This is where [[bilirubin]] deposits in skin, causing an intense [[itch]]. Itching is the most common complaint by people who have liver failure. Often this itch cannot be relieved by drugs. [203] => * [[Ascites|Swelling of the abdomen]], and [[Swelling (medical)|swelling]] of the ankles and feet occurs because the [[Hypoalbuminemia|liver fails to make albumin]]. [204] => * Excessive fatigue occurs from a [[Deficiency (medicine)|generalized loss of nutrients]], [[dietary mineral|minerals]] and vitamins. [205] => * [[bruise|Bruising]] and easy bleeding are other features of liver disease. The liver makes [[Coagulation|clotting factors]], substances which help prevent bleeding. When liver damage occurs, these factors are no longer present and severe bleeding can occur.[http://www.ccfa.org/info/about/complications/liver Extraintestinal Complications: Liver Disease] {{Webarchive|url=https://web.archive.org/web/20101121034708/http://ccfa.org/info/about/complications/liver |date=2010-11-21 }} Crohn's & Colitis Foundation of America. Retrieved 2010-01-22 [206] => * Pain in the upper right quadrant can result from the stretching of Glisson's capsule in conditions of [[hepatitis]] and [[pre-eclampsia]]. [207] => [208] => ===Diagnosis=== [209] => The diagnosis of liver disease is made by [[liver function tests]], groups of [[blood test]]s, that can readily show the extent of liver damage. If [[infection]] is suspected, then other [[serology|serological]] tests will be carried out. A physical examination of the liver can only reveal its size and any tenderness, and some form of [[medical imaging|imaging]] such as an [[ultrasound]] or [[CT scan]] may also be needed. [210] => [211] => Sometimes a [[liver biopsy]] will be necessary, and a tissue sample is taken through a needle inserted into the skin just below the [[rib cage]]. This procedure may be helped by a sonographer providing ultrasound guidance to an interventional radiologist.{{cite journal |last1=Ghent |first1=Cam N |title=Who should be performing liver biopsies? |journal=Canadian Journal of Gastroenterology |volume=23 |issue=6 |pages=437–438 |year=2009 |pmid=19543575 |pmc=2721812 |doi=10.1155/2009/756584 |doi-access=free }} [212] => [213] => {{gallery|mode=packed [214] => |Axial CT anomalous hepatic veins.jpg|Axial CT image showing anomalous hepatic veins coursing on the liver's subcapsular anterior surface{{cite journal|pmid=9843288|year=1998|last1=Sheporaitis|first1=L|last2=Freeny|first2=PC|title=Hepatic and portal surface veins: A new anatomic variant revealed during abdominal CT|volume=171|issue=6|pages=1559–1564|doi=10.2214/ajr.171.6.9843288|journal=AJR. American Journal of Roentgenology}} [215] => |Anterior MIP image of anomalous hepatic veins.jpg|Maximum intensity projection (MIP) CT image as viewed anteriorly showing the anomalous hepatic veins coursing on the anterior surface of the liver [216] => |Lateral MIP CT of anomalous surface hepatic veins.jpg|Lateral MIP view in the same patient as previous image [217] => |CTscanofmyLiver.jpg|A CT scan in which the liver and portal vein are shown [218] => }} [219] => [220] => ===Liver regeneration=== [221] => {{main|Liver regeneration}} [222] => [223] => The liver is the only human internal organ capable of natural [[regeneration (biology)|regeneration]] of lost [[Biological tissue|tissue]]; as little as 25% of a liver can regenerate into a whole liver.{{cite book |doi=10.1515/9783110250794.1 |chapter=Liver Regeneration and Partial Hepatectomy: Process and Prototype |title=Liver Regeneration |date=2011 |last1=Defrances |first1=Marie C. |last2=Michalopoulos |first2=George K. |pages=1–16 |isbn=978-3-11-025078-7 }} This is, however, not true regeneration but rather [[Compensatory growth (organ)|compensatory growth]] in mammals.{{cite book|title=Robbins and Cotran Pathologic Basis of Disease|year=1999|isbn=978-0-8089-2302-2|edition=7th|page=101|last1=Kumar|first1=Vinay|last2=Abbas|first2=Abul K.|last3=Fausto|first3=Nelson}} The lobes that are removed do not regrow and the growth of the liver is a restoration of function, not original form. This contrasts with true regeneration where both original function and form are restored. In some other species, such as zebrafish, the liver undergoes true regeneration by restoring both shape and size of the organ.{{cite journal |last1=Chu |first1=Jaime |last2=Sadler |first2=Kirsten C. |year=2009 |title=New school in liver development: Lessons from zebrafish |journal=Hepatology |volume=50 |issue=5 |pages=1656–1663 |doi=10.1002/hep.23157 |pmid=19693947 |pmc=3093159}} In the liver, large areas of the tissues are formed but for the formation of new cells there must be sufficient amount of material so the circulation of the blood becomes more active.{{cite book|title=Disease and Its Causes|year=1913|publisher=New York Henry Holt and Company London Williams and Norgate The University Press, Cambridge, MA|chapter-url=http://www.gutenberg.org/catalog/world/readfile?fk_files=1499279&pageno=21|author=W.T. Councilman|chapter=Two}} [224] => [225] => This is predominantly due to the [[hepatocyte]]s re-entering the [[cell cycle]]. That is, the hepatocytes go from the quiescent [[G0 phase]] to the [[G1 phase]] and undergo mitosis. This process is activated by the [[Low-affinity nerve growth factor receptor|p75]] receptors.{{cite journal |vauthors=Suzuki K, Tanaka M, Watanabe N, Saito S, Nonaka H, Miyajima A |title=p75 Neurotrophin receptor is a marker for precursors of stellate cells and portal fibroblasts in mouse fetal liver |journal=Gastroenterology |volume=135 |issue=1 |pages=270–281.e3 |year=2008 |pmid=18515089 |doi=10.1053/j.gastro.2008.03.075|doi-access=free }} There is also some evidence of [[bipotential]] [[stem cell]]s, called hepatic oval cells or ovalocytes (not to be confused with oval red blood cells of [[Southeast Asian ovalocytosis|ovalocytosis]]), which are thought to reside in the [[canals of Hering]]. These cells can differentiate into either [[hepatocyte]]s or [[cholangiocyte]]s. Cholangiocytes are the [[epithelial cells|epithelial lining cells]] of the [[bile duct]]s.{{cite journal |vauthors=Tietz PS, Larusso NF |title=Cholangiocyte biology |journal=Current Opinion in Gastroenterology |volume=22 |issue=3 |pages=279–287 |date=May 2006 |pmid=16550043 |doi=10.1097/01.mog.0000218965.78558.bc|s2cid=38944986 }} They are cuboidal epithelium in the small interlobular bile ducts, but become columnar and mucus secreting in larger bile ducts approaching the porta hepatis and the extrahepatic ducts. Research is being carried out on the use of stem cells for the generation of an [[artificial organ|artificial liver]]. [226] => [227] => Scientific and medical works about liver regeneration often refer to the Greek [[Titan (mythology)|Titan]] [[Prometheus]] who was chained to a rock in the [[Caucasus]] where, each day, his liver was devoured by an eagle, only to grow back each night. The myth suggests the [[Ancient Greece|ancient Greeks]] may have known about the liver's remarkable capacity for self-repair.An argument for the ancient Greek’s knowing about liver regeneration is provided by {{Cite journal [228] => | last1 = Chen | first1 = T.S. [229] => | last2 = Chen | first2 = P.S. [230] => | title = The myth of Prometheus and the liver [231] => | journal = Journal of the Royal Society of Medicine [232] => | volume = 87 [233] => | issue = 12 [234] => | pages = 754–755 [235] => | year = 1994 [236] => | pmid = 7853302 [237] => | pmc = 1294986 [238] => }} Counterarguments are provided by {{Cite journal [239] => | last1 = Tiniakos | first1 = D.G. [240] => | last2 = Kandilis | first2 = A. [241] => | last3 = Geller | first3 = S.A. [242] => | doi = 10.1016/j.jhep.2010.02.032 [243] => | title = Tityus: A forgotten myth of liver regeneration [244] => | journal = Journal of Hepatology [245] => | volume = 53 [246] => | issue = 2 [247] => | pages = 357–361 [248] => | year = 2010 [249] => | pmid = 20472318 [250] => | doi-access = free [251] => }} and by {{Cite journal [252] => | last1 = Power | first1 = C. [253] => | last2 = Rasko | first2 = J.E. [254] => | title = Whither prometheus' liver? Greek myth and the science of regeneration [255] => | journal = Annals of Internal Medicine [256] => | volume = 149 [257] => | issue = 6 [258] => | pages = 421–426 [259] => | year = 2008 [260] => | pmid = 18794562 [261] => | doi=10.7326/0003-4819-149-6-200809160-00009 [262] => | citeseerx = 10.1.1.689.8218 [263] => | s2cid = 27637081 [264] => }} [265] => [266] => ===Liver transplantation=== [267] => {{Main|Liver transplantation}} [268] => Human liver transplants were first performed by [[Thomas Starzl]] in the [[United States]] and [[Roy Calne]] in [[Cambridge]], [[England]] in 1963 and 1967, respectively. [269] => [270] => [[File:Liver..JPG|thumb|After resection of left lobe liver tumor]] [271] => [272] => [[Liver transplantation]] is the only option for those with irreversible liver failure. Most transplants are done for chronic liver diseases leading to [[cirrhosis]], such as chronic [[hepatitis C]], [[alcoholism]], and autoimmune hepatitis. Less commonly, liver transplantation is done for [[fulminant hepatic failure]], in which liver failure occurs rapidly over a period of days or weeks. [273] => [274] => Liver [[allograft]]s for [[organ transplantation|transplant]] usually come from donors who have died from fatal [[Traumatic brain injury|brain injury]]. [[Living donor liver transplantation]] is a technique in which a portion of a living person's liver is removed ([[hepatectomy]]) and used to replace the entire liver of the recipient. This was first performed in 1989 for pediatric liver transplantation. Only 20 percent of an adult's liver (Couinaud segments 2 and 3) is needed to serve as a liver allograft for an infant or small child. [275] => [276] => More recently,{{when|date=August 2018}} adult-to-adult liver transplantation has been done using the donor's right hepatic lobe, which amounts to 60 percent of the liver. Due to the ability of the liver to [[regeneration (biology)|regenerate]], both the donor and recipient end up with normal liver function if all goes well. This procedure is more controversial, as it entails performing a much larger operation on the donor, and indeed there were at least two donor deaths out of the first several hundred cases. A 2006 publication addressed the problem of donor mortality and found at least fourteen cases.{{cite journal | author = Bramstedt K | title = Living liver donor mortality: where do we stand? | journal = Am. J. Gastroenterol. | volume = 101 | issue = 4 | pages = 755–759 | year = 2006 | doi = 10.1111/j.1572-0241.2006.00421.x | pmid = 16494593 | s2cid = 205786066 }} The risk of postoperative complications (and death) is far greater in right-sided operations than that in left-sided operations. [277] => [278] => With the recent advances of noninvasive imaging, living liver donors usually have to undergo imaging examinations for liver anatomy to decide if the anatomy is feasible for donation. The evaluation is usually performed by multidetector row [[computed tomography]] (MDCT) and [[magnetic resonance imaging]] (MRI). MDCT is good in vascular anatomy and volumetry. MRI is used for biliary tree anatomy. Donors with very unusual vascular anatomy, which makes them unsuitable for donation, could be screened out to avoid unnecessary operations. [279] => [280] => {{gallery|mode=packed [281] => |CT scan showing liver and kidney.jpg|MDCT image. Arterial anatomy contraindicated for liver donation [282] => |LDLTP.jpg|MDCT image. Portal venous anatomy contraindicated for liver donation [283] => |LDLT volume measure.jpg|MDCT image. 3D image created by MDCT can clearly visualize the liver, measure the liver volume, and plan the dissection plane to facilitate the liver transplantation procedure. [284] => |R vs L Liver by CT.PNG|Phase contrast CT image. Contrast is perfusing the right liver but not the left due to a left portal vein thrombus. [285] => }} [286] => [287] => ==Society and culture== [288] => Some cultures regard the liver as the seat of the [[soul]].{{cite book |last1=Spence |first1=Lewis |author-link1=Lewis Spence |title=Myths and Legends of Babylonia and Assyria |date=2010 |publisher=Cosimo |isbn=978-1-61640-464-2 |page=281 |quote=Now among people in a primitive state of culture the soul is almost invariably supposed to reside in the liver instead of in the heart or brain. }} In [[Greek mythology]], the gods punished [[Prometheus]] for revealing fire to humans by chaining him to a rock where a [[vulture]] (or an [[eagle]]) would peck out his liver, which would regenerate overnight (the liver is the only human internal organ that actually can regenerate itself to a significant extent). Many ancient peoples of the Near East and Mediterranean areas practiced a type of [[divination]] called [[haruspicy]] or [[hepatomancy]], where they tried to obtain information by examining the livers of sheep and other animals. [289] => [290] => In Plato, and in later physiology, the liver was thought to be the seat of the darkest emotions (specifically wrath, jealousy and greed) which drive men to action.{{cite book | title= Kundalini – the evolutionary energy in man | last= Krishna | first= Gopi | author-link= Gopi Krishna (yogi) | author2= Hillman, James | year= 1970 | publisher= Stuart & Watkins | location= London | isbn= 978-1-57062-280-9 | page= 77 | url= https://www.scribd.com/doc/7577310/KUNDALINI-the-evolutionary-energy-in-man | url-status=dead | archive-url= https://web.archive.org/web/20160305055908/https://www.scribd.com/doc/7577310/KUNDALINI-the-evolutionary-energy-in-man | archive-date= 2016-03-05 | author2-link= James Hillman }} The [[Talmud]] (tractate ''Berakhot 61b'') refers to the liver as the seat of [[anger]], with the [[gallbladder]] counteracting this. The [[Persian language|Persian]], [[Urdu]], and [[Hindi]] languages ({{lang|ur|جگر}} or {{lang|hi|जिगर}} or {{transliteration|hi|jigar}}) refer to the liver in figurative speech to indicate courage and strong feelings, or "their best"; e.g., "This [[Mecca]] has thrown to you the pieces of its liver!".[http://www.shawuniversitymosque.org/m/faq_qanda.php?id=94 The Great Battle Of Badar (Yaum-E-Furqan)] {{Webarchive|url=https://web.archive.org/web/20140630115115/http://www.shawuniversitymosque.org/m/faq_qanda.php?id=94 |date=2014-06-30 }}. Shawuniversitymosque.org (2006-07-08). Retrieved 2013-03-19. The term {{transliteration|ur|jan e jigar}}, literally "the strength (power) of my liver", is a term of endearment in Urdu. In Persian slang, {{transliteration|fa|jigar}} is used as an adjective for any object which is desirable, especially women. In the [[Zulu language]], the word for liver ({{lang|zu|isibindi}}) is the same as the word for courage. In English the term 'lily-livered' is used to indicate cowardice from the medieval belief that the liver was the seat of courage. [291] => Spanish {{lang|es|hígados}} also means "courage".{{cite book |title=Diccionario de la lengua española |date=2020 |publisher=ASALE-RAE |edition=23.4 |url=https://dle.rae.es/h%C3%ADgado?m=form#KQjAtQ9 |access-date=29 July 2021 |language=es |chapter=hígado |quote={{lang|es|Ánimo, valentía. U. m. en pl.}}}} [292] => However the secondary meaning of Basque {{lang|eu|gibel}} is "indolence".{{cite book |last1=Azkue |first1=Resurrección María de |title=Diccionario vasco-español-francés ... Dictionnaire basque-espagnol-français .. |date=1905 |publisher=Bilbao, Dirección del autor |page=345 |chapter-url=https://archive.org/details/diccionariovasco01azku/page/345/mode/2up |access-date=29 July 2021 |language=es,fr |chapter=gibel |quote=(Bc, BN-s, R) {{lang|es|cachaza}}, {{lang|fr|calme}}}} [293] => [294] => In biblical Hebrew, the word for liver, {{lang|hbo|כבד}} ({{transliteration|hbo|Kauved}}, stemmed {{transliteration|hbo|KBD}} or {{transliteration|hbo|KVD}}, similar to Arabic {{lang|ar|الكبد}}), also means '''heavy''' and is used to describe '''the rich''' ("heavy" with possessions) and '''honor''' (presumably for the same reason). In the Book of Lamentations (2:11) it is used to describe the physiological responses to sadness by "my liver spilled to earth" along with the flow of tears and the overturning in bitterness of the intestines.{{lang|hbo|כלו בדמעות עיני חמרמרו מעי נשפך לארץ כבדי על שבר בת עמי בעטף עולל ויונק ברחבות קריה}} "My eyes terminated with tears, my intestines overturned with bitterness, my liver spilled to the earth on the breaking of my nation's daughter when a suckling baby lies in the town squares" (Lamentations 2:11) this could be interpreted to be read as my '''honor''' spilled, or '''myself''' being spilled). On several occasions in the [[book of Psalms]] (most notably [[Psalm 16|16]]:9), the word is used to describe happiness in the liver, along with the heart (which beats rapidly) and the flesh (which appears red under the skin). Further usage as '''the self''' (similar to "your honor") is widely available throughout the old testament, sometimes compared to the breathing soul (Genesis 49:6, Psalms 7:6, etc.). An honorable hat was also referred to with this word (Job 19:9, etc.) and under that definition appears many times along with {{lang|hbo|פאר}} {{transliteration|hbo|Pe'er}} - grandeur.[https://www.ruvik.co.il/סיפורי-מילים/כ/כבוד.aspx Kavod - Honor] (in Hebrew, Israeli Linguist Ruvik Rosenthal's website). Rosenthal hypothesized that the term's usage to describe heaviness comes perhaps from the liver being the heaviest of all body parts in some farm animals or in humans. [295] => [296] => These four meanings were used in preceding ancient [[Afro-Asiatic languages]] such as [[Akkadian language|Akkadian]] and Ancient Egyptian preserved in classical Ethiopic [[Ge'ez language]].See [297] => [https://www.assyrianlanguages.org/akkadian/dosearch.php?searchkey=kab%C4%81tu&language=rawakkadian Kabadu] in Akkadian, (From online dictionary at Association Assyrophile de France organization website) [298] => [299] => ===Food=== [300] => {{main|Liver (food)}} [301] => [[File:Finnish maksalaatikko.JPG|thumb|''[[Maksalaatikko]]'', a [[Finland|Finnish]] liver casserole]] [302] => [303] => Humans commonly eat the livers of mammals, fowl, and fish as food. Domestic pig, ox, lamb, calf, chicken, and goose livers are widely available from butchers and supermarkets. In the [[Romance languages]], the anatomical word for "liver" ([[French language|French]] ''foie'', [[Spanish language|Spanish]] ''hígado'', etc.) derives not from the [[Latin language|Latin]] anatomical term, ''jecur'', but from the culinary term ''ficatum'', literally "stuffed with [[figs]]," referring to the livers of geese that had been fattened on figs.{{cite web |title=Foie |url=https://larousse.fr/dictionnaires/francais/foie/34366?q=foie#34314 |website=Larousse.fr |access-date=2019-04-16 |archive-url=https://web.archive.org/web/20180612002718/http://www.larousse.fr/dictionnaires/francais/foie/34366?q=foie#34314 |archive-date=2018-06-12 |url-status=live }} Animal livers are rich in iron, [[Retinol|vitamin A]] and [[Vitamin B12|vitamin B12]]; and [[cod liver oil]] is commonly used as a [[dietary supplement]]. [304] => [305] => Liver can be baked, boiled, broiled, fried, stir-fried, or eaten raw (''asbeh nayeh'' or ''sawda naye'' in [[Lebanese cuisine]], or liver [[sashimi]] in [[Japanese cuisine]]). In many preparations, pieces of liver are combined with pieces of meat or kidneys, as in the various forms of Middle Eastern mixed grill (e.g. ''[[meurav Yerushalmi]]''). Well-known examples include [[liver pâté]], [[foie gras]], [[chopped liver]], and [[leverpastej]]. Liver [[sausage]]s, such as [[Braunschweiger (sausage)|Braunschweiger]] and [[liverwurst]], are also a valued meal. [[Liver sausage]]s may also be used as spreads. A traditional [[South Africa]]n delicacy, [[skilpadjies]], is made of minced lamb's liver wrapped in ''netvet'' (caul fat), and grilled over an open fire. Traditionally, some fish livers were valued as food, especially the [[Common stingray|stingray]] liver. It was used to prepare delicacies, such as poached skate liver on toast in England, as well as the ''beignets de foie de raie'' and ''foie de raie en croute'' in [[French cuisine]].{{cite book [306] => |author= Schwabe, Calvin W. [307] => |title= Unmentionable Cuisine [308] => |url= https://books.google.com/books?id=SiBntk9jGmoC&pg=PA313 [309] => |date= 1979 [310] => |publisher= University of Virginia Press [311] => |isbn= 978-0-8139-1162-5 [312] => |pages= 313– [313] => |access-date= 2015-06-27 [314] => |archive-url= https://web.archive.org/web/20151026160044/https://books.google.com/books?id=SiBntk9jGmoC&pg=PA313 [315] => |archive-date= 2015-10-26 [316] => |url-status= live [317] => }} [318] => [319] => ===Giraffe liver=== [320] => [[File:ESCAYRAC(1853) p454 Planche VIII.jpg|thumb|19th-century drinking scene in [[Kordofan]], home to the [[Humur|Humr tribe]], who made a drink from giraffe liver. Plate from ''Le Désert et le Soudan'' by [[Stanislas d'Escayrac de Lauture]].]] [321] => [322] => The [[Humur|Humr]] are one of the tribes in the [[Baggara]] ethnic group, native to southwestern [[Kordofan]] in [[Sudan]] who speak [[Shuwa Arabic|''Shuwa'']] ([[Chadian Arabic]]), make a non-alcoholic drink from the liver and [[bone marrow]] of the [[giraffe]], which they call ''umm nyolokh''. They claim it is intoxicating (Arabic سكران ''sakran''), causing dreams and even waking [[hallucination]]s.{{cite book |author=Rudgley, R. |author-link=Richard Rudgley |year=1998 |title=The Encyclopedia of Psychoactive Substances |publisher=Abacus |isbn=0-349-11127-8 |pages=20–21}} Anthropologist Ian Cunnison accompanied the Humr on one of their giraffe-hunting expeditions in the late 1950s, and noted that: [323] => :It is said that a person, once he has drunk ''umm nyolokh'', will return to giraffe again and again. Humr, being [[Ansar (Sudan)|Mahdists]], are strict [[Khamr|abstainers]] [from alcohol] and a Humrawi is never drunk (''sakran'') on [[liquor]] or beer. But he uses this word to describe the effects which ''umm nyolokh'' has upon him.{{cite journal |author=Cunnison, Ian |year=1958 |title=Giraffe hunting among the Humr tribe |journal=SNR |volume=39 |pages=49–60}} [324] => [325] => Cunnison's remarkable account of an apparently psychoactive mammal found its way from a somewhat obscure scientific paper into more mainstream literature through a conversation between [[Wendy James (anthropologist)|W. James]] of the Institute of Social and Cultural [[Social anthropology|Anthropology]] at the [[University of Oxford]] and specialist on the use of [[hallucinogen]]s and intoxicants in society, and [[Richard Rudgley|R. Rudgley]], who discussed it in a book on psychoactive drugs for general readers. He speculated that a hallucinogenic compound [[N,N-Dimethyltryptamine]] in the giraffe liver might account for the intoxicating properties claimed for ''umm nyolokh''. [326] => [327] => Cunnison, on the other hand, writing in 1958 found it hard to believe in the literal truth of the Humr's assertion that the drink was intoxicating: [328] => :I can only assume that there is no intoxicating substance in the drink, and that the effect it produces is simply a matter of convention, although it may be brought about [[placebo|subconsciously]]. [329] => [330] => The study of [[entheogen]]s in general – including entheogens of animal origin (e.g. [[hallucinogenic fish]] and [[Colorado River toad|toad venom]]) – has, however, made considerable progress in the sixty-odd years since Cunnison's report; the idea that some intoxicating substance might reside in giraffe livers may no longer be as far-fetched as it seemed to Cunnison. However, to date, proof (or disproof) still waits on detailed analyses of the organ and the beverage made from it. [331] => [332] => ===Arrow/bullet poison=== [333] => Certain [[Tungusic peoples]] of northeast Asia formerly prepared a type of [[arrow poison]] from rotting animal livers, which was, in later times, also applied to [[bullet]]s. Russian anthropologist [[S. M. Shirokogoroff]] wrote that: [334] => :Formerly the using of poisoned arrows was common. For instance, among the Kumarčen, [a subgroup of the [[Oroqen people|Oroqen]]] even in recent times, a poison was used which was prepared from decaying liver. [335] => [336] => :[Note] This has been confirmed by the Kumarčen. I am not competent to judge as to the chemical conditions of production of poison which is not destroyed by the heat of explosion. However, the Tungus themselves compare this method [of poisoning ammunition] with the poisoning of arrows.{{cite book |author-link=S. M. Shirokogoroff |author=Shirokogoroff, S.M. |year=1935 |title=Psychomental Complex of the Tungus |publisher=Kegan Paul, Trench, Trubner & Co. |page=89}} [337] => [338] => ==Other animals== [339] => [[File:Leber Schaf.jpg|thumb|upright|[[Sheep]]'s liver]] [340] => [341] => The liver is found in all [[vertebrate]]s and is typically the largest internal organ. The internal structure of the liver is broadly similar in all vertebrates, though its form varies considerably in different species, and is largely determined by the shape and arrangement of the surrounding organs. Nonetheless, in most species, it is divided into right and left lobes; exceptions to this general rule include [[snake]]s, where the shape of the body necessitates a simple cigar-like form.{{cite book |author1=Romer, Alfred Sherwood |author2=Parsons, Thomas S. |year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location=Philadelphia, PA |pages=354–355 |isbn=978-0-03-910284-5}} [342] => [343] => In neonatal marsupials, it is responsible for the production of blood cells.{{cite journal |last1=Old |first1=J.M. |last2=Selwood |first2=L. |last3=Deane |first3=E.M. |title=A Histological Investigation of the Lymphoid and Immunohaematopoietic Tissues of the Adult Stripe-Faced Dunnart (Sminthopsis macroura) |journal=Cells Tissues Organs |date=2003 |volume=173 |issue=2 |pages=115–121 |doi=10.1159/000068946 |pmid=12649589 }} [344] => [345] => An organ sometimes referred to as a liver is found associated with the digestive tract of the primitive chordate ''[[Amphioxus]]''. Although it performs many functions of a liver, it is not considered a "true" liver but rather a [[homology (biology)|''homolog'']] of the vertebrate liver.{{cite journal |last1=Yuan |first1=Shaochun |last2=Ruan |first2=Jie |last3=Huang |first3=Shengfeng |last4=Chen |first4=Shangwu |last5=Xu |first5=Anlong |title=Amphioxus as a model for investigating evolution of the vertebrate immune system |journal=Developmental & Comparative Immunology |date=February 2015 |volume=48 |issue=2 |pages=297–305 |doi=10.1016/j.dci.2014.05.004 |pmid=24877655 }} [346] => {{cite journal [347] => |last1=Yu |first1=Jr-Kai Sky |last2=Lecroisey |first2=Claire [348] => |last3=Le Pétillon |first3=Yann |last4=Escriva |first4=Hector [349] => |last5=Lammert |first5=Eckhard |last6=Laudet |first6=Vincent [350] => |year=2015 [351] => |title=Identification, evolution and expression of an insulin-like peptide in the cephalochordate ''Branchiostoma lanceolatum'' [352] => |journal=PLOS ONE [353] => |volume=10 |issue=3 |page=e0119461 [354] => |doi=10.1371/journal.pone.0119461 |doi-access=free [355] => |pmid=25774519 |pmc=4361685 |bibcode=2015PLoSO..1019461L [356] => }} [357] => [358] => {{cite journal [359] => |last1=Escriva |first1=Hector |last2=Chao |first2=Yeqing [360] => |last3=Fan |first3=Chunxin |last4=Liang |first4=Yujun [361] => |last5=Gao |first5=Bei |last6=Zhang |first6=Shicui [362] => |year=2012 [363] => |title=A novel serpin with antithrombin-like activity in ''Branchiostoma japonicum'': Implications for the presence of a primitive coagulation system [364] => |journal=PLOS ONE [365] => |volume=7 |issue=3 |page=e32392 [366] => |doi=10.1371/journal.pone.0032392 |doi-access=free [367] => |bibcode=2012PLoSO...732392C |pmid=22427833 |pmc=3299649 [368] => }} [369] => The amphioxus hepatic caecum produces the liver-specific proteins [[vitellogenin]], [[antithrombin]], [[plasmin]]ogen, [[alanine aminotransferase]], and [[insulin]]/[[insulin-like growth factor]]. [370] => {{cite journal [371] => |last1=Guo |first1=Bin |last2=Zhang |first2=Shicui [372] => |last3=Wang |first3=Shaohui |last4=Liang |first4=Yujun [373] => |year=2009 [374] => |title=Expression, mitogenic activity and regulation by growth hormone of growth hormone / insulin-like growth factor in ''Branchiostoma belcheri'' [375] => |journal=Cell and Tissue Research [376] => |volume=338 |issue=1 |pages=67–77 [377] => |doi=10.1007/s00441-009-0824-8 [378] => |pmid=19657677 |s2cid=21261162 [379] => }} [380] => [381] => [382] => ==See also== [383] => *[[Porphyria]] [384] => *[[Johann Joseph Dömling]] (published ''Is the liver a purifying organ'' in 1798) [385] => [386] => ==References== [387] => {{reflist|22em}} [388] => [389] => ===Works cited=== [390] => * {{cite book [391] => |title=Dorland's illustrated medical dictionary [392] => |edition=32nd [393] => |year=2012 [394] => |place=Philadelphia, PA [395] => |publisher=Elsevier / Saunders [396] => |isbn=978-1-4557-0985-4 [397] => |ref={{SfnRef|Dorland's illustrated medical dictionary|2012}} [398] => }} [399] => * {{cite book [400] => |last1=Young |first1=Barbara [401] => |last2=O'Dowd |first2=Geraldine [402] => |last3=Woodford |first3=Phillip [403] => |date=4 November 2013 [404] => |title=Wheater's Functional Histology: A text and colour atlas [405] => |edition=6th [406] => |place=Philadelphia, PA [407] => |publisher=Elsevier [408] => |isbn=978-0-7020-4747-3 [409] => |ref={{harvid|Wheater's|2014}} [410] => }} [411] => [412] => ==External links== [413] => {{Wiktionary|liver}} [414] => {{Commons category|Livers}} [415] => * [https://www.proteinatlas.org/humanproteome/liver Liver at the Human Protein Atlas] [416] => * [http://pie.med.utoronto.ca/VLiver/ VIRTUAL Liver – online learning resource] [417] => * [http://liverenzymes.net Liver enzymes] [418] => * {{cite EB1911 |wstitle=Liver |volume=16 |pages=801–803 |short=1}} with several diagrams. [419] => * {{cite journal |last1=Rizi |first1=Farid |title=Beaver tail liver |website=Radiopaedia.org |date=14 January 2022 |doi=10.53347/rID-96561 |doi-access=free }} [420] => [421] => {{Digestive glands}} [422] => [423] => {{Authority control}} [424] => [425] => [[Category:Liver| ]] [426] => [[Category:Organs (anatomy)]] [] => )
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Liver

The liver is an organ in the human body located in the upper right abdomen. It is the largest internal organ and is essential for various bodily functions.

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It is the largest internal organ and is essential for various bodily functions. The liver performs numerous functions such as filtering blood, detoxifying harmful substances, storing vitamins and minerals, producing bile for digestion, and regulating metabolism. It plays a vital role in breaking down fats, carbohydrates, and proteins, and helps convert food into energy. The liver also plays a key role in removing toxins and waste from the body. Diseases and conditions that affect the liver can have serious consequences and may require medical interventions such as medication, lifestyle changes, or in severe cases, liver transplantation.

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