Stomach

Stomach

generator : adrian Rad BSc ( Hons ) • Reviewer : Nicola McLaren MSc
final reviewed : September 30, 2021
Reading clock time : 14 minutes
Stomach (Gaster); Image: Begoña Rodriguez
Stomach (Gaster); Image: Paul KimStomach (Gaster); Image: National Library of MedicineStomach (Gaster); Image:
stomach
Gaster

Reading: Stomach

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Synonyms:
Ventriculus

The stomach is an organ of the digestive system, specialized in the accumulation and digestion of food. Its anatomy is quite building complex ; it consists of four parts, two curvatures and receives its blood supply chiefly from the celiac trunk. innervation is provided via the vagus nerves and the celiac plexus .
Thanks to the stomach, every homo is technically capable of corroding metallic and picking up new hobbies, such as competitive corrode. These are possible due to the highly potent hydrochloric acidic and the expandable nature of this organ .

Key facts about the stomach
Relations Anteriorly: diaphragm, liver (left lobe), and anterior abdominal wall
Posteriorly: omental bursa (lesser sac), pancreas, left kidney and adrenal gland, spleen, and splenic artery
Superiorly: esophagus and diaphragm
Inferiorly and laterally: transverse mesocolon
Parts Cardia, fundus, body, pyloric part
Mnemonic:  Cows Find Bulls Passionate
Functions Mechanical and chemical digestion, absorption, hormone secretion
Layers Mucosa, submucosa, muscularis externa and serosa
Mnemonic:  M.S.M.S
Blood supply Gastric arteries, gastroomental arteries, short gastric arteries, posterior gastric arteries, gastroduodenal artery
Innervation Parasympathetic: vagus nerve (CN X)
Sympathetic: celiac plexus (T5-T12)
Lymphatics Juxtacardial, gastric, short gastric, gastroomental, and pyloric lymph nodes
Drain to celiac nodes →  intestinal lymphatic trunk → cisterna chyli →  thoracic duct
Clinical point Hiatal hernia

In this article we ’ ll research every aspect of the abdomen mentioned above, including the accurate position of the digest within the abdominal cavity .

Anatomy

Location

The stomach is the most elaborate region of the digestive system, lying between the esophagus and duodenum. More precisely, the stomach spans the area between the cardiac and pyloric orifices of the gastrointestinal tract. It is covered and connected to early organs by peritoneum. The lesser omentum connects the stomach to the liver and then extends around the stomach. The greater omentum then continues inferiorly from the stomach, hanging from it like a curtain.The peritoneum has a twist course that requires visual image for a accomplished reason, then study the follow resources to avoid taking a incorrectly turn. They trace the trajectory of the peritoneum and provide you with an overview of the entire digestive arrangement, including labeling worksheets and a sketch unit :


Digestive system

Digestive system

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The stomach is located inside the abdominal cavity in a modest area called the bed of the stomach, onto which the stomach lies when the body is in a supine position, or lying face up. It spans respective regions of the abdomen, including the epigastric, umbilical, left hypochondriac, and left flank regions. The abdomen besides has some precise anatomic relations and comes in contact with several neighboring structures .

Anatomical relations of the stomach
Anteriorly Diaphragm, liver (left lobe), and anterior abdominal wall
Posteriorly Omental bursa (lesser sac), pancreas, left kidney and adrenal gland, spleen, and splenic artery
Superiorly Esophagus and diaphragm
Inferiorly and laterally Transverse mesocolon


Stomach in situ

Stomach in situ

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Parts

The stomach consists of several important anatomic parts. The four chief sections of the stomach are the cardia, fundus, body, and pyloric part. As the name implies, the cardia surrounds the cardiac orifice, which is the opening between the esophagus and the abdomen. It is the first section that ingested food passes through, representing the inflow depart. The fundus is the superior dilation of the digest, which is located superiorly relative to the horizontal plane of the cardiac orifice .
Anatomy of the stomach - anterior view
Anatomy of the stomach (anterior view)
next, we have the corpus, or gastric body, which is the largest region of the harmonium. ultimately, the pyloric part represents the escape part of the digest, passing stomach contents into the duodenum. The pylorus is promote divided into two clear-cut areas – the pyloric antrum connected to the stomach and the pyloric canal connected to the duodenum. The contents of the pyloric canal enroll into the duodenum via the pyloric orifice, the open and closing of which are controlled by the pyloric sphincter ( pylorus ), a circular layer of polish muscleman .
As you might notice in the stomach diagram illustrated above, the electric organ has a characteristic J-shape created by two unequal curvatures. The longer and convex curvature located on the exit of the stomach is called the greater curvature, this starts from the cardiac notch that is formed between the esophageal edge and fundus. In contrast, the short concave curvature found to the right is the lesser curvature. The latter contains a little notch called the angular incisure which marks the line of intersection between the torso and pyloric separate of the stomach .

Mnemonic

You might be wondering if there ‘s an easy room to remember the parts of the stomach. Of course there is and we ‘re about to tell you ! Just remember the idiom ‘ C ows F ind B ulls P assionate ‘, which stands for :

  • Cardium
  • Fundus
  • Body
  • Pylorus

immediately to cement your newly acquired cognition about the parts of the stomach take a count at the following survey quiz !

Function

The main function of the stomach involves mechanical and chemical digestion of ingested food. Ingested food enters the digest from the esophagus via the cardiac orifice, falling into gastric juice produced by the abdomen. insistent muscle contractions physically churn food particles, breaking them into smaller fragments which are shuffle with the gastric juice. The assorted enzymes and hydrochloric acid ( ph 1-2 ) in the gastric juice break food down even more, forming a semi-liquid substance called chyme. This ultimately passes into the duodenum through the pyloric orifice by a process called gastric peristalsis. Being a muscular electric organ, the stomach can distend quite a draw, accumulating anywhere between 2 and 3 liters of food .
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In addition to digestion, this organ is besides involved in a minor degree of absorption. specifically, it can absorb water, caffeine, and a little proportion of absorb ethyl alcohol. The stomach besides plays a character in controlling secretion and motion within the digestive tract by releasing respective hormones such as gastrin, cholecystokinin, secretin, and gastric inhibitory peptide .

Microscopic anatomy

so far, we ’ ve seen the external, macroscopic structure of the stomach. Let ’ s prima donna deep to see its inner and microscopic structure. The stomach consists of four histological layers called, from department of the interior to exterior, mucosa, submucosa, muscularis externa, and serous membrane .
Stomach wall. Stain: H&E. Low magnification.
Stomach wall. Stain: H&E. Low magnification.
When the abdomen is empty or contains identical little quantities of food, it is in a contract, shrink express. The mucosa has a wrinkled expression, consisting of ridges called gastric folds, or ruga. During dilatation of the harmonium, the gastric folds disappear. Along the lesser curvature of the stomach, a temp, continuous furrow called gastric canal is formed between the gastric folds. This facilitates the passage of saliva and fluids during swallow .
Gastric folds (Plicae gastricae); Image: Rebecca BettsGastric canal (Canalis gastricus); Image: Rebecca BettsSurface mucous cells (Mucocytus superficiei); Image: Gastric pit (Foveola gastrica); Image: Gastric gland (proper) (Glandula gastrica propria); Image:
Gastric folds
Plicae gastricae

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Synonyms:
Gastric rugae, Rugae gastricae

The mucous membrane is lined by simple columnar epithelium which is covered by a protective, alkaline mucous layer. The epithelial layer contains numerous invaginations, called gastric pits, that extend deeper into structures called gastric glands. Depending on the depart of the stomach, these glands consist of respective cell types. mucous neck cells produce the mucous layer, while parietal cells secrete hydrochloric acid. Chief cells publish pepsinogen, an inactive precursor that will transform into the active pepsin enzyme in a low ph environment. In turn, neuroendocrine cells release assorted hormones mentioned previously .
Gastric gland. Stain: H&E. High magnification.
Gastric gland. Stain: H&E. High magnification.
Moving outwardly, the next layer is the submucosa. It consists of informal connection weave containing lineage vessels and nerves .

Oblique fibers of muscular coat of stomach (Fibrae obliquae tunicae muscularis gastris); Image: Rebecca BettsCircular layer of muscular coat of stomach (Stratum circulare tunicae muscularis gastris); Image: Rebecca BettsLongitudinal layer of muscular coat of stomach (Stratum longitudinale tunicae muscularis gastris); Image: Rebecca Betts
Oblique fibers of muscular coat of abdomen

Fibrae obliquae tunicae muscularis gastris

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Synonyms:
Oblique muscle fibers of stomach, Fibrae obliquae tunicae muscularis ventriculi
,
Oblique brawn fibers of digest, Fibrae obliquae tunicae muscularis gizzard, show more …
The third layer is called muscularis externa and consists of three smooth muscle sub-layers. From inner to external, they are called inner devious, center round, and external longitudinal. The inner oblique layer is located throughout the stallion harmonium and works in unison with the other layers to produce the physical gesticulate and contractions of the digest required for digestion. The middle circular layer is located concentrically to the farseeing bloc of the digest throughout the harmonium and plays an significant function in forming the pyloric sphincter. The external longitudinal layer is situated in the two curvatures of the stomach in a longitudinal fashion. last but not least, the serosa consists of the intuitive peritoneum that covers the stomach .
Test your cognition on the microanatomy of the stomach with our quiz.

Mnemonic

You can easily remember the layers of the stomach rampart using a mnemonic. ‘ M. S. M. S ‘, which stands for :

  • Mucosa
  • Submucosa
  • Muscularis externa
  • Serosa


Stomach

Stomach

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Blood vessels

The overall blood supply of the stomach originates from the abdominal aorta and is provided from two anastomotic systems along the curvatures and several direct branches. The anastomosis along the lesser curvature is created by the union of the right and left gastric arteries which originate from the common hepatic artery and coeliac torso respectively. The greater curvature anastomosis is formed by the union of the right and left gastroomental arteries ( gastroepiploic ), which originate from the gastroduodenal and splenic arteries respectively .
Arteries of the stomach, liver, and spleen - anterior view
Arteries of the stomach, liver, and spleen (anterior view)
The splenic artery besides sends out short and posterior gastric arteries, which directly supply the fundus and amphetamine body of the digest. The pyloric character receives arterial blood from the gastroduodenal artery, which stems from the park liverwort artery. The veins draining the stomach follow the run and terminology of the arteries very closely. They ultimately drain into three large vessels called the hepatic portal, splenic, and superior mesenteric veins .
Do you want to find out how every blood vessels twists and turns as it snails towards its respective gastric part ?


Arteries of the stomach, liver and gallbladder

Arteries of the stomach, liver and gallbladder

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Innervation

The stomach receives involuntary innervation by the autonomic skittish system ( ANS ). Parasympathetic innervation originates from the anterior and buttocks vagal trunks, which stem from the leave and right vagus nerves ( CN X ), respectively. The anterior vagal trunk chiefly supplies a part of the front tooth surface of the stomach, a well as the pylorus. The larger posterior vagal trunk innervates the remaining anterior come on, angstrom well as the entire back tooth surface. parasympathetic nervous system excitation is creditworthy for inducing gastric secretion and motility, equally well as relaxation of the pyloric sphincter during gastric emptying. The vagus nerves besides carry sensations of annoyance, fullness, and nausea from the stomach .
Anterior vagal trunk (Truncus vagalis anterior); Image: Yousun KohAnterior gastric branches of anterior vagal trunk (Rami gastrici anteriores trunci vagalis anterioris); Image: Paul KimCeliac ganglia (Ganglia coeliaca); Image: Irina Münstermann
Anterior vagal trunk
Truncus vagalis front tooth

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In line, sympathetic excitation is provided by the celiac plexus. The steel impulses originate from the fifth to twelfth pectoral spinal anesthesia nerves ( T5-T12 ) and travel to the coeliac plexus via the greater splanchnic nerves. harmonic excitation is responsible for inhibiting gastric motility and constricting the pyloric sphincter, frankincense preventing gastric empty .

Lymphatics

Lymphatics of the stomach and liver - anterior view
Lymphatics of the stomach and liver (anterior view)
The lymphatic drain of the stomach is variable between individuals but the lapp regional lymph nodes are by and large involved. These are the :

  • juxtacardial nodes (a.k.a. paracardial nodes),
  • gastric nodes (of which there are left and right, corresponding to the left and right gastric arteries),
  • short gastric nodes (corresponding to the short gastric arteries)
  • gastroomental nodes (a.k.a. gastroepiploic, of which there are left and right following the arteries of the same names),
  • pyloric nodes (made up of the supra-, infra- (or sub-) and retropyloric groups).

These groups drain into the celiac nodes which drain through the intestinal lymphatic trunk into the cisterna chyli ( if present ) and from there flow into the thoracic duct. Some drain will often occur from the abdomen to the splenic and superior mesenteric nodes .
For more about the lymphatic drain of the stomach take a front at the trace resources :


Lymphatics of the stomach, liver and gallbladder

Lymphatics of the stomach, liver and gallbladder

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Hiatal hernia

A hiatal hernia is a bulge of part of the stomach into the mediastinum through the esophageal hiatus of the diaphragm. Any gastric separate can be involved, but the most common situation is a protrusion of the gastroesophageal junction ( sliding hiatal hernia ), accounting for 95 % of cases. The fundus of the stomach ( paraesophageal hiatal hernia ), multiple parts, or even the entire organ can herniate into the mediastinum, making the pathology quite varied .
There are respective causes of hiatal hernia, such as injury, congenital malformations, and previous operation. possibly the most common, however, is advance historic period which results in sabotage of the diaphragm and widening of the esophageal suspension, facilitating protrusions .
Patients suffering from hiatal hernias are by and large asymptomatic but can complain of non-specific symptoms like heartburn ( heartburn ), vomit, dysphagia, epigastric discomfort, postprandial fullness, and nausea. Due to their asymptomatic nature, hiatal hernia are by and large diagnosed by the way during upper endoscopy or imaging performed for other specific reasons .
asymptomatic hiatal hernia are treated conservatively, managing the symptoms of gastroesophageal ebb disease for case. diagnostic hernia, however, require surgical intervention .

Sources

References :

  • Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). Clinically Oriented Anatomy (7th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
  • Peter J Kahrilas (2019): Hiatus hernia, S. Grover (Ed.) UpToDate. Waltham, MA: UpToDate Inc. Retrieved from https://www.uptodate.com
  • Standring, S. (2016). Gray’s Anatomy (41tst ed.). Edinburgh: Elsevier Churchill Livingstone.

Illustrators :

  • Anatomy of the stomach (anterior view) – Rebecca Betts
  • Arteries of the stomach, liver, and spleen (anterior view) – Irina Münstermann
  • Lymphatics of the stomach and liver (anterior view) – Begoña Rodriguez

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