Chapter 31 - Stomach and Duodenum Flashcards
What is the approximate capacity range of the equine stomach?
5 L to 15 L.
Where is the equine stomach primarily located?
On the left side of the abdomen with only the pyloric
region of the stomach to the right side of the midline. Its most
caudal component is the fundus, which lies adjacent to the 14th and 15th rib spaces
What is the most caudal component of the equine stomach?
The fundus.
What anatomical feature attaches the cardia to the diaphragm?
The gastrophrenic ligament.
What ligaments comprise the lesser omentum?
Hepatogastric and hepatoduodenal ligaments.
What artery provides blood supply to the equine stomach?
The celiac artery.
Where does venous drainage from the stomach occur?
Via gastric veins to the portal vein.
What marks the start of the duodenum?
The pylorus.
Which ducts open into major papila of the duodenum?
The bile and pancreatic ducts.
What is the role of the duodenocolic fold?
It attaches the duodenum to the transverse colon and proximal descending colon.
How many portions has the stomach?
The stomach can be divided
into several regions, including the 1. cardia at the opening of the
esophagus, the 2. fundus (which forms a blind sac), the 3. body, and
4. the pyloric region.
The greater omentum attaches along the
the greater curvature of the
stomach, and it blends into the gastrophrenic ligament
The greater omentum forms a blind potential space called the _________________(2w)
omental bursa
The entrance to this bursa is the _____________(2w)
entrance to this bursa is the epiploic foramen,
Where is located the epiploic foramen?
Between the caudate process of the liver
Right lobe of the pancreas
Borded dorsally caudal vena cava
Ventrally by portal vein
The lesse omentum connects the ____________(1w) and ____(1w) to the liver and consists of two ligaments the _____________ and _________________
The lesser omentum, which connects
the stomach and duodenum to the liver, consists of the hepatogastric
and hepatoduodenal ligaments
The duodenum makes a curving sharply toward the dorsal aspect of the abdomen this curve creates the ________ ___________ ___________(3w) within which the pancreas lies
The duodenum makes a curving sharply toward the dorsal aspect of the abdomen this curve creates the cranial duodenal flexure within which the pancreas lies
The bile and pancreatic dutcs open within the _____ _________ ____________(3w) and enter the duodenum at the ____ ______________ ___________(3w)
The bile and pancreatic ducts open within the cranial duodenal flexure, and enter the duodenum at the major duodenal papilla
What is the primary function of pepsinogen in the stomach?
To begin breaking down proteins.
What are the four regions of the stomach based on mucosal lining?
Nonglandular, cardiac, proper gastric, and pyloric mucosa.
What does the margo plicatus signify in the equine stomach?
The abrupt transition from stratified squamous mucosa to cardiac glandular mucosa.
What type of cells are found in the proper gastric mucosa?
Parietal cells and zymogen cells.
What hormone do G-cells secrete?
Gastrin.
Which type of cells secrete somatostatin?
D-cells.
What specialized glands are found in the proximal duodenal submucosa?
Brunner glands.
What is the role of Brunner glands?
To secrete mucin and factors that protect and repair the duodenal mucosa.
What mediates bicarbonate secretion in the duodenum?
Prostaglandin E2 (PGE2).
What is the principal secretory channel in the jejunum and ileum?
Cystic fibrosis transmembrane conductance regulator (CFTR).
What is the migrating myoelectric complex (MMC)?
A pattern of myoelectrical activity in the gastrointestinal tract.
Where is the MMC initiated in horses?
In the duodenum.
What can cause bile to appear in the stomach?
Reflux of duodenal contents during gastric emptying.
What effect does detomidine have on duodenal motility?
It markedly reduces duodenal motility.
What is transepithelial electrical resistance a measure of?
Ion permeability.
What layers comprise the stratified squamous mucosa?
Stratum corneum, stratum transitionale, stratum spinosum, and basal stratum germinativum.
Which layer primarily contributes to barrier function in the squamous mucosa?
Interepithelial tight junctions.
What is the pH at which exposure to acid significantly damages equine stratified mucosa?
pH 1.7.
What does the gastric mucosa secrete to protect against acid injury?
Mucus and bicarbonate.
What mechanism does the gastric mucosa use to expel H+ ions?
Epithelial Na+/H+ exchangers.
What region of the stomach is often referred to as a blind sac?
The fundus.
What anatomical structure is located between the caudate process of the liver and the right lobe of the pancreas?
The epiploic foramen.
What does the term “omental bursa” refer to?
A potential space formed by the greater omentum.
What significant transition occurs at the margo plicatus?
The transition from stratified squamous mucosa to cardiac glandular mucosa.
What is the clinical significance of preserving the C1 nerve during surgery?
To maintain function of the thyrohyoideus muscle.
What factors can stimulate bicarbonate secretion in the duodenum?
Factors released in response to pH changes.
What cells in the gastric mucosa amplify HCl secretion?
Enterochromaffin-like (ECL) cells.
How does the equine stomach’s size compare to its body size?
It is relatively small compared to the horse’s body size.
What anatomical feature is primarily responsible for the attachment of the greater omentum?
The greater curvature of the stomach.
What are the main protective mechanisms of the equine stomach against injury?
Stratified squamous mucosa and the secretion of mucus and bicarbonate.
Which structures enter the major duodenal papilla?
bile and pacreatic duts
Which structures enter the minor duodenal papilla?
acessory ancreatic duct
The dilated ampulla taht comes out from pylorus and goes dorsal towards the dorsal aspect of the abdomen is the cranial duodenal flexure. The cauda duodenal flexure resumes to what?
At its most dorsal aspect, the duodenum forms the caudal duodenal flexure that runs across the base of the cecum and curves caudally around the root of the mesentery to reach the left side of the abdomen.
duodenum then attaches to the transverse colon what is the name of the fold?
duodenocolic fold
Name the irrigation of the duodenum
Celiac artery that gives off–> gastrodudodenal artery and more distaly cranial mesenteric artery
There is potential collateral circulation for the duodenum?
Yes, the duodenum receives its blood supply from both the celiac artery, which gives off the gastroduodenal artery, and more distally the cranial mesenteric artery
What are the four regions of the stomach based on mucosal lining?
nonglandular stratified squamous epithelium,
cardiac epithelium,
proper gastric mucosa (glandular mucosa),
and pyloric mucosa.
What do the hormones gastrin and somatostatin promote?
they promote ehnance or reduce gastric acid secretion
The duodenal mucosa has a single layer of columnar epithelium. what is the function?
serving both secretory and absorptive functions
proximal duodenal submucosa contains specialized Brunner glands. Brunner glands are unusual in horses in that they are comprised of both ______ and_______ glands
Brunner glands are unusual in horses in that they are comprised of both mucous and serous tubuloacinar glands
These glands empty into a common duct that enters the base of the duodenal mucosal crypts, and collectively secrete 3 things
mucin
trefoil peptides
epidermal growth factor
bicarbonate to elevate the pH coming from the stomach
What senese the pH in the duodenal mucosa?
prostaglandin E2 (PGE2)
migrating myoelectric complex (MMC) consists in how many phases?
three phases of myoelectrical activity, is initiated in the horse in the duodenumthree phases of myoelectrical activity, is initiated in the horse in the duodenum
What is the baseline transepithelial resistance measurement of equine stratified squamous epithelium?
Approximately 2000 to 3000 Ohms·cm².
Which layer of the stratified squamous epithelium primarily contributes to barrier function?
Interepithelial tight junctions in the stratum corneum.
What does the gastric mucosa secrete to protect against acid injury?
Mucus and bicarbonate.
How do epithelial Na+/H+ exchangers function in the gastric mucosa?
They expel H+ ions once the cell reaches a critical pH.
What is the main mechanism of defense in stratified squamous mucosa?
Its exceptional impermeability due to high transepithelial resistance.
What portion of the stomach is most commonly involved in ulceration in horses?
The stratified squamous epithelium.
What factors can enhance the damaging effects of HCl in the equine stomach?
Bile salts and short-chain fatty acids.
What role do short-chain fatty acids play in gastric ulceration?
They damage Na+ transport activity in the stratum germinativum.
How does bile reflux impact the equine stomach?
Bile salts adhere to the squamous epithelium and can trigger damage at low pH levels.
What condition can disrupt the normal pH stratification in the equine stomach?
Periods of fasting.
Which bacteria is commonly associated with gastric ulcers in humans but not in horses?
Helicobacter pylori.