Lambung: Perbedaan antara revisi
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JohnThorne (bicara | kontrib) k Melindungi "Lambung": 1. Vandalisme berulang: Artikel biologi penting yang seharusnya disunting oleh pakar ([Sunting=Hanya untuk pengguna terdaftar otomatis] (selamanya)) |
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{{Infobox anatomy
| Name = Lambung
| Latin = Ventriculus
| Greek = Gaster
| GraySubject = 247
| GrayPage = 1161
| Image = Stomach_diagram.svg
| Caption = Lambung (''stomach'') terletak di tengah agak ke kiri dalam tubuh manusia.
| Width =
| Image2 = Illu stomach.jpg
| Caption2 = 1. [[#Struktur|Body of stomach]] 2. [[#Struktur|Fundus]] 3. [[#Struktur|Anterior wall]] 4. [[Curvatures of the stomach|Greater curvature]] 5. [[Curvatures of the stomach|Lesser curvature]] 6. [[#Sections|Cardia]] 9. [[Pylorus#Pyloric sphincter|Pyloric sphincter]] 10. [[Pylorus#Antrum|Pyloric antrum]] 11. [[Pylorus#Pyloric canal|Pyloric canal]] 12. [[Angular incisure]] 13. [[Angular incisure|Gastric canal]] 14. [[Rugae]]<ref>Diagram from [http://training.seer.cancer.gov/ss_module07_ugi/unit02_sec02_anatomy.html cancer.gov]. [[Copyright status of work by the U.S. government|Work of the United States Government]]</ref>
| ImageMap =
| MapCaption =
| Precursor = [[Foregut]]
| System = [[:en:Human digestive system|Digestive system]]
| Artery = [[Right gastric artery]], [[left gastric artery]], [[right gastro-omental artery]], [[left gastro-omental artery]], [[short gastric arteries]]
| Vein = [[Right gastric vein]], [[left gastric vein]], [[right gastroepiploic vein]], [[left gastroepiploic vein]], [[short gastric veins]]
| Nerve = [[Celiac ganglia]], [[vagus nerve]]<ref>{{GeorgiaPhysiology|6/6ch2/s6ch2_30| }}</ref>
| Lymph = [[Celiac lymph nodes]]<ref>{{NormanAnatomy|stomach|The Stomach }}</ref>
| MeshName = Stomach
| MeshNumber = A03.556.875.875
| Code =
| Dorlands = seven/000100936
| DorlandsID = Stomach
}}
[[Berkas:Estómago.svg|thumb|200px|right|Lambung: <br />1) Esofagus <br />2) Kardia <br />3) Fundus <br />4) Selaput lendir <br />5) Otot lapisan <br />6) Lambung mukosa <br /> 7) Tubuh perut <br />8) Pilorik antrum <br />9) Pilorus <br />10) Usus dua belas jari (''duodenum'')]]
'''Lambung''' ({{lang-en|stomach}}; {{lang-nl|maag}}) atau ventrikulus berupa suatu kantong yang terletak di bawah sekat rongga badan.
Fungsi lambung secara umum adalah tempat di mana makanan dicerna dan sejumlah kecil sari-sari makanan diserap.
== Struktur ==
[[File:Gray1046.svg|thumb|left|upright=1.2|Daerah-daerah lambung manusia]]
Pada manusia dewasa, volume lambung dalam keadaan santai, hampir kosong, adalah sekitar 75 mililiter.<ref>[http://news.bbc.co.uk/1/hi/health/7274820.stm Key to way stomach expands found]. BBC (3 March 2008)</ref> Merupakan organ tubuh yang dapat mengembang (''distensible''), dapat menampung sampai sekitar satu liter makanan.<ref>{{cite book |author=Sherwood, Lauralee |title=Human physiology: from cells to systems |publisher=Wadsworth Pub. Co |location=Belmont, CA |year=1997 |pages= |isbn=0-314-09245-5 |oclc= 35270048|doi=}}</ref> Lambung bayi manusia yang baru lahir hanya dapat menampung sekitar 30 mililiter.
== Daerah ==
Lambung dapat dibagi menjadi tiga daerah, yaitu daerah
# ''Kardia.''
Baris 15 ⟶ 48:
'''3. Pilorus''' adalah bagian bawah, daerah yang berhubungan dengan usus 12 jari atau sering disebut [[duodenum]].
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In humans, the stomach lies between the [[oesophagus]] and the [[duodenum]] (the first part of the [[small intestine]]). It is in the [[quadrant (anatomy)|left upper part]] of the [[abdominal cavity]]. The top of the stomach lies against the [[diaphragm (anatomy)|diaphragm]]. Lying behind the stomach is the [[pancreas]]. A large double fold of visceral [[peritoneum]] called the [[greater omentum]] hangs down from the [[Curvatures of the stomach|greater curvature]] of the stomach. Two sphincters keep the contents of the stomach contained; the [[oesophagus#Sphincters|lower oesophageal sphincter]] (found in the cardiac region), at the junction of the oesophagus and stomach, and the [[pyloric sphincter]] at the junction of the stomach with the duodenum.
The stomach is surrounded by [[parasympathetic nervous system|parasympathetic]] (stimulant) and [[sympathetic nervous system|sympathetic]] (inhibitor) [[plexuses]] (networks of blood vessels and nerves in the [[anterior]] gastric, [[Posterior (anatomy)|posterior]], [[Anatomical terms of location#Superior and inferior|superior]] and [[Anatomical terms of location#Superior and inferior|inferior]], celiac and myenteric), which regulate both the secretory activity of the stomach and the motor (motion) activity of its muscles.
=== Sections ===
In classical [[anatomy]], the human stomach is divided into four sections, beginning at the ''gastric cardia'',<ref>{{SUNYAnatomyLabs|37|06|01|03}} – "Abdominal Cavity: The Stomach"</ref> each of which has different cells and functions.
* The ''cardia'' is where the contents of the oesophagus empty into the stomach. The cardia is defined as the region following the "z-line" of the gastroesophageal junction, the point at which the [[epithelium]] changes from [[stratified squamous epithelia|stratified squamous]] to [[columnar]]. Near the cardia is the lower oesophageal sphincter.<ref>{{cite book|editor-first=F. Charles |editor-last=Brunicardi |editor2-first=Dana K. |editor2-last=Andersen |title=Schwartz's principles of surgery|date=2010|publisher=McGraw-Hill, Medical Pub. Division|location=New York|isbn=0071547703|edition=9th|display-editors=etal}}</ref>
* The ''fundus'' (from Latin, "bottom") is formed by the upper curvature of the organ.
* The ''body'' is the main, central region.
* The [[pylorus]] (from Greek, "gatekeeper") is the lower section of the organ that facilitates emptying the contents into the small intestine.
=== Blood supply ===
[[Image:Stomach blood supply.svg|thumb|center|600px|Schematic image of the blood supply to the human stomach: [[left gastric artery|left]] and [[right gastric artery]], [[left gastroepiploic artery|left]] and [[right gastroepiploic artery]] and [[short gastric artery]].<ref name=Moore150>{{cite book |author1=Anne M. R. Agur |author2=Moore, Keith L. |title=Essential Clinical Anatomy (Point (Lippincott Williams & Wilkins)) |publisher=Lippincott Williams & Wilkins |location=Hagerstown, MD |year= 2007|pages= |isbn=0-7817-6274-X |oclc= 172964542|doi=}}; p. 150</ref>]]
The lesser curvature of the human stomach is supplied by the [[right gastric artery]] inferiorly, and the [[left gastric artery]] superiorly, which also supplies the cardiac region. The greater curvature is supplied by the [[right gastroepiploic artery]] inferiorly and the [[left gastroepiploic artery]] superiorly. The fundus of the stomach, and also the upper portion of the greater curvature, is supplied by the short gastric artery which arises from the splenic artery.
===Histology===
[[Image:Normal gastric mucosa intermed mag.jpg|thumb|upright=0.6|[[Micrograph]] showing a cross section of the human stomach wall, in the body portion of the stomach. [[H&E stain]].]]
{{Main article|Gastrointestinal wall}}
Like the other parts of the gastrointestinal tract, the human stomach walls consist of an outer [[mucosa]], inner [[submucosa]], [[muscularis externa]], and [[serosa]].
The [[gastric mucosa]] of the stomach consists of the [[epithelium]] and the [[lamina propria]] (composed of loose connective tissue), with a thin layer of [[smooth muscle]] called the [[muscularis mucosae]] separating it from the submucosa beneath. The [[submucosa]] lies under the mucosa and consists of [[fibrous connective tissue]], separating the mucosa from the next layer. [[Meissner's plexus]] is in this layer. The [[muscularis externa]] lies beneath the submucosa and is unique from other organs of the gastrointestinal tract, consisting of three layers:
* The ''inner oblique layer:'' This layer is responsible for creating the motion that churns and physically breaks down the food. It is the only layer of the three which is not seen in other parts of the [[digestive system]]. The antrum has thicker skin cells in its walls and performs more forceful contractions than the fundus.
* The ''middle circular layer:'' At this layer, the [[pyloric valve|pylorus]] is surrounded by a thick circular muscular wall which is normally tonically constricted forming a functional (if not anatomically discrete) pyloric [[sphincter]], which controls the movement of [[chyme]] into the [[duodenum]]. This layer is concentric to the longitudinal axis of the stomach.
* [[Auerbach's plexus]] (AKA myenteric plexus) is found between the outer longitudinal and the middle circular layer and is responsible for the innervation of both (causing peristalsis and mixing)
* The ''outer longitudinal layer'' is responsible for moving the bolus towards the pylorus of the stomach through muscular shortening.
The stomach also possesses a [[serosa]], consisting of layers of connective tissue continuous with the [[peritoneum]].
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=== Dinding lambung ===
'''Dinding lambung tersusun menjadi empat lapisan, yakni :'''
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'''4. gerak peristaltik''' (gerak menggelombang). Gerak peristaltik menyebabkan makanan di dalam lambung diaduk-aduk. Lapisan terluar yaitu ''serosa'' berfungsi sebagai lapisan pelindung perut. Sel-sel di lapisan ini mengeluarkan sejenis cairan untuk mengurangi gaya gesekan yang terjadi antara perut dengan anggota tubuh lainnya.
=== Kelenjar lambung===
<!--{{Main article|Gastric glands}}-->
Pada manusia terdapat tiga jenis sel pada lapisan-lapisan mukosa atau kelenjar lambung (''[[:en:gastric glands|gastric glands]]''):
{| class="wikitable"
| '''Lapisan lambung''' || '''Nama''' || '''Sekresi''' || '''Daerah lambung''' || '''Pewarnaan''' (''Staining'')
|-
| Isthmus || Sel goblet/[[:en:Foveolar cell|sel foveolar]] || lapisan gel [[:en:Mucus|mukus]] || Fundus, Kardia, Pilorus || Jernih
|-
| Badan kelenjar (''body'') || [[:en:Parietal cell|Sel parietal (oxyntic)]] || [[:en:Gastric acid|Asam lambung]] dan [[:en:intrinsic factor|faktor intrinsik]] || Fundus saja || [[:en:Acidophilic|Asidofilik]]
|-
| Dasar kelenjar (''base'') || [[:en:Gastric chief cell|Sel chief (zymogenic)]] || [[:en:Pepsinogen|Pepsinogen]] dan [[:en:gastric lipase|lipase]] || Fundus saja || [[:en:Basophilic|Basofilik]]
|-
| Dasar kelenjar (''base'') || [[Enteroendocrine cells|Enteroendocrine (APUD) cells]] || [[Hormon]] gastrin, histamin, endorphin, serotonin, cholecystokinin dan somatostatin|| Fundus, kardia, pilorus || –
|}
<gallery>
Image:Gray1053.png|'''[[:en:cardiac glands|Kelenjar kardia]]''' (pada [[:en:cardia|kardia]] manusia)
Image:Gray1054.png|'''[[:en:pyloric glands|Kelenjar pilorus]]''' (pada [[:en:pylorus|pilorus]] manusia)
Image:Gray1055.png|'''[[:en:fundic glands|Kelenjar fundus]]''' (pada [[:en:Fundus (stomach)|fundus]] manusia)
</gallery>
'''1. Sel goblet''' berfungsi untuk memproduksi ''mucus'' atau lendir untuk menjaga lapisan terluar sel agar tidak rusak karena enzim pepsin dan asam lambung.
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'''3. Sel chief''' berfungsi untuk memproduksi [[pepsinogen]], yaitu [[enzim]] [[pepsin]] dalam bentuk tidak aktif. Sel chief memproduksi dalam bentuk tidak aktif agar enzim tersebut tidak mencerna protein yang dimiliki oleh sel tersebut yang dapat menyebabkan kematian pada sel tersebut.
== Enzim ==
Di bagian dinding lambung sebelah dalam terdapat kelenjar-kelenjar yang menghasilkan getah lambung. Aroma, bentuk, warna, dan selera terhadap makanan secara refleks akan menimbulkan sekresi getah lambung. Getah lambung mengandung asam lambung (HCI), pepsin, musin, dan [[renin]]. Asam lambung berperan sebagai pembunuh mikroorganisme dan mengaktifkan enzim pepsinogen menjadi pepsin.
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* ''[[Musin]]'' merupakan mukosa protein yang melicinkan makanan.
* ''[[Renin]]'' merupakan enzim khusus yang hanya terdapat pada mamalia, berperan sebagai kaseinogen menjadi kasein. Kasein digumpalkan oleh Ca<sup>2+</sup> dari susu sehingga dapat dicerna oleh pepsin. Tanpa adanya renim susu yang berwujud cair akan lewat begitu saja di dalam lambuing dan usus tanpa sempat dicerna.
* ''[[HCl|HCl(Asam Klorida)]]'' merupakan asam yang berfungsi sebagai enzim, yang berguna untuk membunuh kuman dan bakteri pada makanan.
Kerja enzim dan pelumatan oleh otot lambung mengubah makanan menjadi lembut seperti bubur, disebut ''chyme'' (kim) atau bubur makanan. Otot lambung bagian pilorus mengatur pengeluaran kim sedikit demi sedikit dalam duodenum. Caranya, otot pilorus yang mengarah ke lambung akan relaksasi (mengendur) jika tersentuk kim yang bersifat asam.
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Pada lambung terdapat kelenjar oksintik ({{lang-en|oxyntic gland}}) yang memproduksi [[hormon]] [[Ghrelin|GHS]]. Hormon lain yang disekresi antara lain adalah [[somatostatin|GHIH]].
== Referensi ==
{{reflist}}
{{sistem pencernaan}}
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