Stomach and Duodenum Flashcards
What is the peritoneum?
A serous membrane with 2 layers which encloses the peritoneal cavity in the abdomen and pelvis
2 layers of the peritoneum
- Parietal layer
- Visceral layer
Parietal layer function
Lines the walls of the abdomen and pelvis
Visceral layer function
Encloses many of the abdominal and pelvic organs
Peritoneal cavity sacs
Greater and lesser sacs
Where does the greater sac extend from?
From the diaphragm to pelvic cavity
Where is the lesser sac located?
Behind the stomach in the upper abdomen
Where do the greater and lesser sacs communicate?
Through the epiploic foramen
Function x 2 of the sacs
- Support the viscera
- Provides pathways for blood vessels and lymph to travel to and from the viscera.
Contents of the GI tract
- Mouth
- Pharynx
- Esophagus
- Stomach
- Duodenum
- Ileum
- Jejunum
- Large intestine
What can the stomach stretch until?
4 L
X 4 Functions of the stomach
- Regulate rate of emptying into small intestine. This is slow
- Mechanical and chemical breakdown of food
- Inhibit bacterial growth (HCL) activates pepsinogen, the precursor to pepsin (breaks down proteins)
- Provide intrinsic factor for vitamin B12 absorption. Vit B12 is important for erythrocytes production and normal neurological function
Regions that the stomach lies in?
Lies in left hypochondrial, epigastric and umbilical region
Quadrants that the stomach lies in
Right and Left upper quadrants
Where does the cardia of stomach lie at
T10
Where does the pylorus of the stomach lie at?
L1
Where does the cardiac orifice usually lie?
Posterior to the 6th left costal cartilage, 2–4 cm from the median plane at the level of the T10-11
What is the pyloris?
A concentration of circular smooth muscle that controls the release of gastric contents to the duodenum
What does the rugae allow for?
Allows distension of the stomach as it fills up
Where does the body of the stomach lie?
Posterior to left rib 6
Which parts of the duodenum are fixed / mobile?
Proximal and distal ends
are fixed midportion is mobile
Where is the cardiac sphincter between?
The oesophagus and the stomach
Function of cardiac sphincter
It prevents backflow of food and digestive enzymes.
Function of the fundus of the stomach
It begins digestion of proteins and mixes together stomach contents
Function of the body of the stomach
It also digests proteins and blends materials found in stomach.
Where is the lesser curvature?
Forms the shorter concave right border of the stomach.
Where is the greater curvature?
Forms the longer convex left border of the stomach.
Pylorus function
Contracts to empty materials from the stomach into the small intestine
Function of pyloric sphincter
Prevents materials and digestive enzymes from escaping into the small intestine before digestion is completed in the stomach.
Connections of the
pg 14
What are the omenta?
Fused peritoneal folds, subdivisions of visceral peritoneum
Where does the greater omentum run from and surround?
Greater curvature to transverse colon and posterior abdominal wall and angs like an apron, surrounding the small intestine
Ligaments of the greater omentum?
The gastrophrenic, gastrocolic and gastrosplenic ligaments
Where does the lesser omentum go and run as?
Lesser curvature to liver as the hepatogastric and hepatoduodenal ligaments
What opening does the lesser omentum contain?
The opening into the lesser sac or foramen of Winslow.
4 layers of the gut wall
1) Outer visceral peritoneum
2) Smooth muscle (skeletal
in upper ¼ esophagus)
3) Submucosal layer
4) Inner lining of mucous membrane
What is the outer visceral peritoneum made of?
Serosa - tough collagenous connective tissue
What other layer does the stomach have?
An inner oblique layer
What is the submucosal layer composed of?
Loose connective tissue
Blood vessels, nerves and lymph
What type of epithelium is the inner lining of muscus membrane?
Simple columnar epithelium
What does the inner lining of mucus membrane contain and function?
- Cilia to increase op
- Goblet cells to produce mucous
3 muscle groups in the stomach
- A longitudinal layer
- A circular layer
- A longitudinal layer
What is the longitudinal layer of the stomach continuous with?
With the longitudinal muscle layer of the esophagus and duodenum
Where is the circular layer of the stomach thickest and what does it form?
Thickest in the pylorus - forms the pyloric sphincter.
Where is the inner oblique layer best developed?
In the cardia and body
Where does the myenteric plexus (Auerbachs plexus) lie?
Where does the myenteric plexus (Auerbachs plexus) lie?
In the connective tissue lamina
What is the function of the myenteric plexus (Auerbachs plexus)?
It separates the circular from the longitudinal muscle fibers - motor innervation to both layers of the muscular layer of the gut, both parasympathetic and sympathetic input
What are gastric areas?
When mucosa is divided by furrows into small irregular elevations.
What are gastric pits?
The surface of each gastric area studded with minute depressions.
What is the longest part of the alimentary canal?
The small intestine
Where does most enzymatic digestion occur?
small intestine
Where are most enzymes secreted by?
Pancreas
3 subdivisions of duodenum and length percentage
◦ Duodenum – 5% of length
◦ Jejunum – almost 40%
◦ Ileum – almost 60%
Blood supply to small intestine
Superior mesenteric artery
Where do veins of small intestine drain into?
Hepatic portal vein
What is the suspensory muscle of the duodenum?
Ligament of Treitz
What forms the “Ligament of Treitz”?
Smooth muscle and elastic fibres from the right diaphragmatic crus to parts 3 and 4 of the duodenum
pg
23
Is the duodenum intraperitoneal or retroperitoneal?
Retroperitoneal (under peritoneum)
What does the duodenum receive and via where? x2
- Bile from liver and gallbladder via bile duct
- Enzymes from pancreas via main pancreatic duct
What does the left gastric artery supply?
- Oesophagus
- Stomach
Where does the left gastric artery curve around?
Curves around to travel in the lesser curve of the stomach
What does the splenic artery supply?
- Spleen
- Stomach
What does the splenic artery give rise to en route to the spleen?
Gastric branches
What does the left gastric artery form on the lesser curve?
Forms an anastomosis with the right gastric artery
Where does the right gastric artery arise from?
From the common hepatic artery
What does the gastroepiploic artery come from?
Common hepatic artery
Where does the right gastroepiploic artery run alone?
The greater curve of stomach
What does the right gastroepiploic artery form after running alone the greater curve?
Forms an anastomosis with the left gastroepiploic artery
What is the left gastroepiploic artery a branch of?
Splenic artery
What is the fundus of the stomach supplied by?
The vasa brevia (short gastric arteries)
Where do the vasa brevia (or short gastric arteries) arise from?
From near the termination of the splenic artery
Branches of the hepatic portal system x 3 and where
1) Splenic Vein - foregut
2) Superior Mesenteric Vein – mid gut
3) Inferior Mesenteric Vein – hind gut
Where does the hepatic portal vein?
The liver
Where does the vagus nerve pass?
Along with esophagus through diaphragm and branches
pg
30
What occurs in gastrophageal reflux?
Stomach contents, including acid, can travel backward up the esophagus. There may be no symptoms, or reflux may cause heartburn or coughing.
Gastroesophageal reflux disease (GERD):
When symptoms of reflux become bothersome or occur frequently, they’re called GERD. Infrequently, GERD can cause serious problems of the esophagus.
Dyspepsia
Another name for stomach upset or indigestion. Dyspepsia may be caused by almost any benign or serious condition that affects the stomach.
Gastric ulcer (stomach ulcer)
An erosion in the lining of the stomach, often causing pain and/or bleeding. Gastric ulcers are most often caused by NSAIDs or H. pylori infection.
Peptic ulcer disease
Ulcers in either the stomach or the duodenum (the first part of the small intestine) are regarded as peptic ulcer disease.
Crohns disease
A chronic disease that causes inflammation and pain in your digestive tract leading to diarrhoea and weight loss
Zollinger-Ellison syndrome (ZES)
One or more tumours that secrete hormones that lead to increased acid production. Severe GERD and peptic ulcer disease result from this rare disorder.
Gastric varices
In people with severe liver disease, veins in the stomach may swell and bulge under increased pressure. Called varices, these veins are at high risk for bleeding, although less so than esophageal varices are.
What is secreted in Zollinger-Ellison syndrome and what does it cause?
Secrete large amounts of gastrin, which causes your stomach to produce too much HCL by parietal cells leading to peptic ulsers.
How is Zollinger-Ellison syndrome treated?
By reducing the amount of gastric acid your stomach produces.
Medications called proton pump inhibitors reducethe production of stomach acid
and allow the ulcers to heal.
lansoprazole (Prevacid), omeprazole (Prilosec), pantoprazole (Protonix),
esomeprazole (Nexium), and rabeprazole (Aciphex),
Mucosa and Lamina Propria epithelium type
Simple columnar epithelium
Submucosa function
Separates the muscularis from the mucosa.
What does the submucosa consist of?
Coarse collagenous fibers and many elastic fibers, plus blood vessels, lymph vessels, nerves, and the plexus of Meissner. Glands are absent.
Function of mucous cells
Secrete mucus to protect epithelial cells from enzymes
& acid
Parietal cells function
Secrete HCl (for protein digestion) & intrinsic factor (for B12 absorption)
What do chief cells contain
Zymogens granules
What is the abundant of the gastric cells?
Chief cells
Function of chief cells
Secrete pepsinogen, activated by HCl; to become proteolytic enzyme pepsin.
Gastric enteroendocrine cells functions
Secretes gastrin, which stimulates the release of HCL by parietal cells
What is a lacteal?
A network of blood and lymph capillaries
pg
41
