Stomach Flashcards
What is the location of the stomach
Expanded part of alimentary tract between the esophagus and small intestine.
What can cause a change in shape of the abdomen
different body types, diaphragmatic movements, stomach contents, position of the person.
How much can a stomach hold
2-3 L of food
What is the size of a newborn stomach
30ml
Functions of the stomach
-accumulation of ingested food -chemically and mechanically prepares food for digestion -enzymatic digestion - creates chyme
What is Chyme?
is a semi-liquid mixture created from the breakdown of food by gastric juices
What are the four parts of the stomach
Cardia Fundus Body Pyloric part
What is the cardia?
the part of the stomach surrounding the cardial orifice
What is the fundus of the heart?
-dilated superior part that is related to the left dome of the diaphragm - between the esophagus and the fundus.
Which level does the fundus reach?
the 5th intercostal space
What could cause dilation of the fundus?
gas, fluid, food or a combination of the three
Describe the location of the body of the stomach?
major part of stomach between fundus and pyloric antrum
What are the two parts of the pyloric area of the stomach?
funnel-shaped - Pyloric antrum (wide part) - Pyloric canal (narrow part)
What is responsible for controlling discharge of gastric contents? How could you identify it?
The phylorus - thickening of circular layer of smooth muscle.
What initiates emptying of the stomach?
Intragastric pressure greater than resistance of pylorus
What is the position of the stomach when the pyloric orifice is reduced?
tonically contracted
When is the chyme passed through the pyloric canal and orifice into small intestine?
irregular intervals
What causes chyme to pass through the pyloric canal?
gastric peristalis
What are the two curvatures of the stomach?
lesser curvature - shorter concave boarder which has the ANGULAR INCISURE at 2/3 the distance. greater curvature - longer convex border of the stomach
What is the name of the junction between body and the pyloric part of the stomach?
Angular incisure
What is the stomach covered in?
a continuous mucus layer that protects it surface from the gastric contents
What happens when the gastric mucosa is contracted?
forms gastric folds or gastric rugae, longitudinal ridges.
Where are gastric folds more prominent and when do they disappear?
More prominent: pyloric part and along greater curvature. Less prominent: stomach distention
What is a gastric canal (furrow)?
temporarily formed fold on the lesser curvature of the stomach during swallowing do to the longitudinal gastric folds.
What do gastic canals form on the lesser curvature?
There is a firm attachment of the gastric mucosa to the muscular layer.
Which layer of the stomach does not have an oblique layer?
lesser fold
What passes to the stomach when the stomach is empty?
saliva and small amounts of masticated foods and fluids.
Where is the stomach not covered in peritoneum?
where blood vessesl run along curvature small area posterior to cardial orifice
Describe the anterior location of the stomach.
diaphyragm, left lobe of liver anterior abdominal wall
Describe the posterior location of the stomach.
related to the omental bursa and pancrease
What does the posterior surface of the stomach form?
anterior wall of the omental bursa
Describe from superior to inferior the formation of the stomach bed.
- left dome of the diaphragm
- spleen
- left kidney
- suprarenal gland
- splenic artery
- pancreas
- transverse mesocolon colon
What can cause the stomach to push anteriorly?
pancreatic pseudo-cyst abscesses in the omental bursa
What cause adherence of the stomach to omental bursa?
Pancreatis ( inflammation of the pancreas) this adherence is do to the close relationship of the posterior wall to the pancreas
Histal Hernia
protrusion of stomach into the mediastinum through esophageal hiatus
Who is more commonly prone to Histal Hernia?
middle age weakness of diaphragm and widening of esphageal hiatus
Differentiate between parasophageal hiatal hernia and sliding hiatel hernia?
Parasophageal hiatel hernia: less common, cardia in normal position, a pounch of peritoneum often containing fundus passes through the esophageal hiatus. - No regurgitation of gastric contents Sliding Hiatal hernia: abdominal parts of esophagus, cardia and fundus slide above esophageal hiatus into thorax. may have regurgitation of gastric contents.
When is a sliding hiatal hernia more prominent?
when an individual is lying down or bending over.
Why is regurgitation possible in a sliding hiatal hernia?
weakening of the clamping action of the right crus of the diaphragm or the inferior end of esophagus is weak.
Congenital Diaphragmatic Hernia
herniation of stomach and intestine through a large defect in the diaphragm called foramen of Bochdalek (posterolateral defect) 1/2200 newborns high mortality due to pulmonary hypoplasia.
What is the foramen of Bochdalek?
defect in closure of the pericardioperitoneal canal by the pleuroperitoneal membrane
What are the three anosomoses that supply blood to the abdomen?
Lesser curvature: right and left gastric arteries greater curvature - right and left gastro-omental arteries fundus and upper body- short and posterior gastric arteries.
Are the gastric arteries parallel to the veins?
yes, gastric arteries have the same position and course as the arteries.
What abdominal veins drain into the portal vein?
right and left gastric veins
What abdominal vein empties into the superior mesenteric vein?
right gastro-omental vein
What vein is utilized to identify the pyloris?
prepyloric vein which ascends over the pyloris to the right gastric vein
What are the three main lymph nodes of the stomach?
gastric lymph nodes on lesser surface gastro-omental lymph nodes on greater surfaces celiac lymph node.
Where does lymph from the superior two thirds of the stomach drain into?
right and left gastric vessels to the gastric lymph nodes
Where does lymph from the fundas and superior part of the body into?
short gastric arteries and left gastro-omental vessels to the pancreatico-splenic lymph nodes
Where does lymph from the right 2/3 of the inferior third of the stomach drain into?
right gastro-omental vessels to the pyloric lymph nodes
Where does lymph from the left 1/3 of the greater curvature drain into?
the short gastric and splenic vessels to the pancreaticduodenal lymph nodes.
What is the parasympathetic nerve supply to the stomach?
anterior and posterior vagal trunks which enter abdomen through the esophageal hiatus.
Describe the anterior vegal trunk and its pathway to the stomach?
derived from the left vegas nerve anterior surface of esophagus runs towards the lesser curvature of the stomach
Describe the posterior vegal trunk and its pathway to the stomach?
From the right vegas nerve posterior surface of esophagus passes towards the lesser curvatur of the stomach where is becomes a celiac branch which runs into the celiac plexus
Describe symphathetic innervation of the stomach.
T6-T9 via the greater splanchnic nerve -> celiac plexus -> around the plexus that surround the gastric and gastro-omental arteries
What does it mean if a baby has pylorospasm?
spasmodic contraction of pylorus (2-12 weeks of age) failure of the smooth muscle to relax normally baby full because food not passing into the duodenum signs: increased vomiting
Congentital Hypertrophic Pyloric Stenosis
marked thickening of smooth muscle in the pylorus pylorus is elongated and hard. 1/150 males infants 1/750 female infants the hard pylorus makes gastric emptying difficult causing proximal part of stomach to dilate. believed to have a congenital component
Carcinoma of the stomach
may be palpable if in body or pyloric part biopsy can be done using gastroscopy and air
Why is it difficult to surgically treat a stomach carcinoma
due to the large amount of lymph nodes surrounding the stomach it is difficult to remove all the lymph nodes. The nodes along the splenic vessels can be excised by removing the spleen, gastrosplenic and splenorenal ligaments and the body and tail of the pancreas. Resection of the greater omentum can removed the nodes along the gastro-omental vessels removal of the aortic and celiac nodes around the head of the pancreas is difficult.
What kind of gastrectomy is common and how can anastomoses aid in this surgery?
partial removal of the stomach is common and the anastomose of the stomach provide good collateral circulation making the loss of several arteries to have no effect.
Describes what happens to the arteries when the pyloric antrum is removed?
the greater omentum is incised parallel and inferior to the right gastro-omental artery thus ligating the omental branch of the artery. there is no degeneration of the omentum as there is still the left gastro-omental artery intact.
Which lymph node would show malignancy in advance cancer?
celiac lymph nodes which all gastric nodes drain into.
Which lymph nodes need to be removed if cancer is in the pyloric region?
pyloric lymph nodes and right gastro-omental lymph nodes.
What is the difference between a gastric ulcer and a peptic ulcer
Gastric ulcers: open lesions of the stomach mucosa Peptic ulcers: lesions of the pyloric canal or duodenum
What is the most common cause of gastric ulcers?
increased stress alcohol cause increased acidity of the stomach creating an environment for the growth of H. pylori. H. Pylori erodes the stomach mucosa lining, inflaming the mucosa which is not vulnerable to gastric contents.
What is a vagotomy?
surgical section of the vegas nerve to prevent the secretion of acid of parietal cells in the stomach. often preformed in conjuction with resection of the ulcerated area
What is a truncal vagotomy?
surgical section of the vegal trunk rarely preformed because of the innervation of other abdominal structures
What is a selective gastric vagotomy?
stomach is denervated but the vagal branches of pyloris, liver and biliary ducts, intestines and celiac plexus are preserved.
What is a selective proximal vagotomy?
denervates the area in which the parietal cells are located. goal: affect acid-producing cells sparing motility
What is a partial gastrectomy? and why is it prefered over total?
removal of part of the stomach, due to anastomoses the artery supply may be ligated without serious affect to the stomach.
Why does the omentum not degenerate when it is ligated during a gastrectomy?
The omentun does not degenerate because the anastomose with other arteries, such as the omental branches of the left gastro-omental artery are still intact.
What lymph nodes should be removed during a partial gastrectomy to prevent spread of the cancer?
if in the pyloric area - remove pyloric lymph nodes and the right gastro-omental lymph nodes.
if cancer metasizes it is important to remove the celiac lymph odes
Why would some one have referred back pain when they have a gastric ulcer?
If an individuals gastic ulcer erodes through the stomach wall into the pancreas an individual would be subjected to back pain.
The pain is referred to the epigastric region because the stomach pain afferent reach T7 and T8 spinal sensory ganglion through the greater splanchnic nerve
What carried pain impulses from the stomach?
visceral afferent fibers that accompany sympathetic nerves.
What is the surface anatomy of cardial orifice?
lies posterior to the 6th left costal cartilage, 2-4cm from the median plane at T11 vertebra
What is the surface anatomy of the fundus?
lies posterior to the 6th rib in midclavicular line
What is the surface anatomy of the greater curvature of the stomach?
inferior to the left 10th left cartilage before turning medial to reach the pyloric antrum
What is the surface anatomy of the lesser curvature?
passes from the right side of the cardia to the pyloric antrum; the most inferior part of the curvature is marked by the angular incisure, which lies left of the midline.
What is the surface anatomy of the pyloric part of the stomach in supine position
9th costal cartiliage at the level of L1 vertebra, the pyloric orifice is approximately 1.25cm left of midline
What is the surface anatomy of the pylorus in erect position?
lies on the right side, L2-L4
