How to Draw a Plane Stomach
Stomach
The stomach is an organ of the digestive system, specialized in the aggregating and digestion of nutrient. Its beefcake is quite complex; information technology consists of 4 parts, two curvatures and receives its claret supply mainly from the celiac trunk. Innervation is provided via the vagus fretfulness and the celiac plexus.
Thanks to the tummy, every homo is technically capable of corroding metal and picking up new hobbies, such as competitive eating. These are possible due to the extremely potent hydrochloric acid and the expandable nature of this organ.
| 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: 1000.S.K.S |
| Blood supply | Gastric arteries, gastroomental arteries, short gastric arteries, posterior gastric arteries, gastroduodenal artery |
| Innervation | Parasympathetic: vagus nervus (CN X) Sympathetic: celiac plexus (T5-T12) |
| Lymphatics | Juxtacardial, gastric, short gastric, gastroomental, and pyloric lymph nodes Bleed to celiac nodes → abdominal lymphatic trunk → cisterna chyli → thoracic duct |
| Clinical point | Hiatal hernia |
In this article we'll explore every aspect of the stomach mentioned above, including the precise position of the stomach within the intestinal cavity.
Contents
- Anatomy
- Location
- Parts
- Function
- Microscopic beefcake
- Mnemonic
- Blood vessels
- Innervation
- Lymphatics
- Hiatal hernia
- Sources
+ Show all
Anatomy
Location
The stomach is the most dilated role of the digestive system, lying between the esophagus and duodenum. More precisely, the stomach spans the region between the cardiac and pyloric orifices of the gastrointestinal tract. It is covered and connected to other organs by peritoneum. The lesser omentum connects the breadbasket to the liver and then extends around the tummy. The greater omentum and so continues inferiorly from the stomach, hanging from information technology similar a curtain.The peritoneum has a convoluted grade that requires visualization for a complete understanding, and so study the following resources to avert taking a wrong turn. They trace the trajectory of the peritoneum and provide you lot with an overview of the unabridged digestive system, including labeling worksheets and a study unit:
The stomach is located inside the abdominal cavity in a pocket-size expanse called the bed of the stomach, onto which the tummy lies when the torso is in a supine position, or lying confront. Information technology spans several regions of the abdomen, including the epigastric, umbilical, left hypochondriac, and left flank regions. The breadbasket also has some precise anatomical relations and comes in contact with several neighboring structures.
| Anteriorly | Diaphragm, liver (left lobe), and inductive 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
The tum consists of several important anatomical parts. The 4 main sections of the tum are the cardia, fundus, torso, and pyloric function. As the name implies, the cardia surrounds the cardiac orifice, which is the opening between the esophagus and the tummy. Information technology is the first department that ingested nutrient passes through, representing the arrival part. The fundus is the superior dilation of the tum, which is located superiorly relative to the horizontal plane of the cardiac orifice.
Next, we have the corpus, or gastric torso, which is the largest part of the organ. Finally, the pyloric part represents the outflow section of the stomach, passing tum contents into the duodenum. The pylorus is farther divided into two singled-out areas – the pyloric antrum continued to the tum and the pyloric canal connected to the duodenum. The contents of the pyloric canal enter into the duodenum via the pyloric orifice, the opening and closing of which are controlled by the pyloric sphincter (pylorus), a circular layer of smooth musculus.
Equally you lot might notice in the stomach diagram illustrated to a higher place, the organ has a characteristic J-shape created by two diff curvatures. The longer and convex curvature located on the left of the stomach is chosen the greater curvature, this starts from the cardiac notch that is formed betwixt the esophageal edge and fundus. In contrast, the shorter concave curvature found to the correct is the lesser curvature. The latter contains a small notch called the angular incisure which marks the line of intersection between the body and pyloric part of the tummy.
Mnemonic
You might exist wondering if in that location'southward an like shooting fish in a barrel way to recall the parts of the stomach. Of class there is and we're about to tell you! Just recall the phrase ' Cows Find Bulls Passionate', which stands for:
- Cardium
- Fundus
- Body
- Pylorus
At present to cement your newly acquired knowledge near the parts of the stomach take a look at the post-obit study quiz!
Role
The primary part of the breadbasket involves mechanical and chemic digestion of ingested food. Ingested food enters the stomach from the esophagus via the cardiac orifice, falling into gastric juice produced past the stomach. Repetitive muscle contractions physically churn nutrient particles, breaking them into smaller fragments which are mixed with the gastric juice. The diverse enzymes and hydrochloric acid (pH 1-2) in the gastric juice suspension food down even more, forming a semi-liquid substance chosen chyme. This ultimately passes into the duodenum through the pyloric orifice past a process called gastric peristalsis. Being a muscular organ, the stomach can distend quite a lot, accumulating anywhere between ii and 3 liters of food.
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In add-on to digestion, this organ is as well involved in a modest caste of absorption. Specifically, it can blot water, caffeine, and a pocket-size proportion of ingested ethanol. The breadbasket also plays a function in decision-making secretion and motion within the digestive tract by releasing several hormones such as gastrin, cholecystokinin, secretin, and gastric inhibitory peptide.
Microscopic anatomy
Then far, we've seen the external, macroscopic structure of the breadbasket. Let'southward dive deeper to run into its internal and microscopic structure. The breadbasket consists of four histological layers called, from interior to exterior, mucosa, submucosa, muscularis externa, and serosa.
When the breadbasket is empty or contains very small quantities of food, it is in a contracted, shrunken state. The mucosa has a wrinkled aspect, consisting of ridges called gastric folds, or rugae. During distension of the organ, the gastric folds disappear. Along the lesser curvature of the stomach, a temporary, continuous furrow called gastric culvert is formed betwixt the gastric folds. This facilitates the passage of saliva and fluids during swallowing.
The mucosa is lined by simple columnar epithelium which is covered by a protective, alkali metal mucous layer. The epithelial layer contains numerous invaginations, called gastric pits, that extend deeper into structures called gastric glands. Depending on the part of the stomach, these glands consist of various jail cell types. Mucous neck cells produce the mucous layer, while parietal cells secrete hydrochloric acrid. Main cells release pepsinogen, an inactive forerunner that will transform into the active pepsin enzyme in a low pH surroundings. In plow, neuroendocrine cells release various hormones mentioned previously.
Moving externally, the next layer is the submucosa. Information technology consists of loose connective tissue containing claret vessels and fretfulness.
The third layer is chosen muscularis externa and consists of three polish muscle sub-layers. From internal to external, they are chosen inner oblique, middle circular, and external longitudinal. The inner oblique layer is located throughout the entire organ and works in unison with the other layers to produce the physical motion and contractions of the stomach required for digestion. The middle circular layer is located concentrically to the long axis of the breadbasket throughout the organ and plays an important part in forming the pyloric sphincter. The external longitudinal layer is situated in the ii curvatures of the stomach in a longitudinal fashion. Concluding but not least, the serosa consists of the visceral peritoneum that covers the tum.
Test your knowledge on the microanatomy of the stomach with our quiz.
Mnemonic
You tin easily recollect the layers of the stomach wall using a mnemonic. ' Chiliad.Due south.Grand.Due south', which stands for:
- Mucosa
- Due southubmucosa
- 1000uscularis externa
- Serosa
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 celiac trunk respectively. The greater curvature anastomosis is formed by the spousal relationship of the right and left gastroomental arteries (gastroepiploic), which originate from the gastroduodenal and splenic arteries respectively.
The splenic artery also sends out short and posterior gastric arteries, which directly supply the fundus and upper body of the stomach. The pyloric part receives arterial blood from the gastroduodenal artery, which stems from the mutual hepatic artery. The veins draining the stomach follow the grade and classification 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 detect out how every claret vessels twists and turns as it snails towards its respective gastric portion?
Innervation
The stomach receives involuntary innervation by the autonomic nervous organization (ANS). Parasympathetic innervation originates from the anterior and posterior vagal trunks, which stem from the left and correct vagus fretfulness (CN X), respectively. The anterior vagal trunk mainly supplies a portion of the anterior surface of the stomach, as well as the pylorus. The larger posterior vagal trunk innervates the remaining anterior surface, as well as the entire posterior surface. Parasympathetic innervation is responsible for inducing gastric secretion and motion, also equally relaxation of the pyloric sphincter during gastric emptying. The vagus nerves besides carry sensations of pain, fullness, and nausea from the stomach.
In contrast, sympathetic innervation is provided past the celiac plexus. The nerve impulses originate from the fifth to twelfth thoracic spinal nerves (T5-T12) and travel to the celiac plexus via the greater splanchnic fretfulness. Sympathetic innervation is responsible for inhibiting gastric motility and constricting the pyloric sphincter, thus preventing gastric elimination.
Lymphatics
The lymphatic drainage of the stomach is variable between individuals just the same regional lymph nodes are generally involved. These are the:
- juxtacardial nodes (a.grand.a. paracardial nodes),
- gastric nodes (of which there are left and right, corresponding to the left and right gastric arteries),
- brusque gastric nodes (corresponding to the short gastric arteries)
- gastroomental nodes (a.chiliad.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 catamenia into the thoracic duct. Some drainage will often occur from the tummy to the splenic and superior mesenteric nodes.
For more than about the lymphatic drainage of the tum take a look at the following resource:
Hiatal hernia
A hiatal hernia is a protrusion of part of the tum into the mediastinum through the esophageal hiatus of the diaphragm. Any gastric part can be involved, but the virtually common state of affairs 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 several causes of hiatal hernias, such as trauma, congenital malformations, and previous surgery. Perhaps the most common, nevertheless, is avant-garde age which results in weakening of the diaphragm and widening of the esophageal hiatus, facilitating protrusions.
Patients suffering from hiatal hernias are generally asymptomatic but can mutter of non-specific symptoms like heartburn (pyrosis), regurgitation, dysphagia, epigastric discomfort, postprandial fullness, and nausea. Due to their asymptomatic nature, hiatal hernias are mostly diagnosed incidentally during upper endoscopy or imaging performed for other specific reasons.
Asymptomatic hiatal hernias are treated conservatively, managing the symptoms of gastroesophageal reflux disease for instance. Symptomatic hernias, however, require surgical intervention.
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