Lecture 21: The Stomach and Pancreas Flashcards
What is peristalsis?
The contraction of muscle to move food to the stomach
What the oesophageal hiatus?
The hole in the diaphragm that the oesophagus passes through to get to the stomach
What is the lower oesophageal sphincter (including its function)?
The sphincter passing through the stomach that prevents reflux of food back up the oesophagus
What are the four main parts of the stomach called?
Cardia
Fundus
Body
Pylorus (pyloric antrum)
Which part of the stomach does the oesophagus open up into?
the cardia
What is the significance of the fundus part of the stomach?
there are lots of gastric glands here and it is where all the gases collect
What is the significance of the pylorus part of the stomach?
it contains the pyloric sphincter for regulating the movement of luminal contents into the duodenum of the small intestine
What is an omentum?
a double layer of peritoneum that connects one organ to another
What does the lesser omentum connect?
the stomach to the liver
What does the greater omentum connect?
the stomach to the transverse colon
What does the lesser omentum contain?
blood vessels
What does the greater omentum contain and what are the roles of these things?
- fat tissue to provide padding for the abdomen
- has clusters of immune cells to destroy pathogens in the peritoneal cavity
The four layers of the gut tube are mucosa, submucosa, muscularis and adventitia. How has the structure of the muscularis changed in the stomach and why?
The muscularis has been modified for motility and mixing to mechanically breakdown food and drive it towards the small intestine.
In the stomach, there is three layers (inner oblique, middle circular, outer longitudinal layer) instead of just the circular and longitudinal layers.
How does the thickness of the of the pyloris differ from the thickness of the fundus and why?
It is thicker in the pyloris because the stomach needs to mechanically breakdown food distally, closer to the small intestine.
What are rugae and what is their advantage?
they are temporary folds that allow for the expansion of the stomach
this is important to expand to accomodate more food
What is the role of sphincters in storage?
they control whether the food leaves the stomach or not and therefore they can keep food in the stomach for digestion.
Which layer of the gut wall are the rugae in and why?
the submucosa because the connective tissue in the submucosa allows them to flatten out
The four layers of the gut tube are mucosa, submucosa, muscularis and adventitia. How has the structure of the mucosa changed in the stomach and why?
The simple squamous epithelium has changed to simple columnar epithelium which invaginate down into the lamina propria to form glands.
This increases the surface area for secretion
Are glands in the mucosa of the stomach permanent
Yes
What four things do we need to be secreted from the glands?
- Acid and enzymes for digestion
- mucus for protection
- hormones for regulation
What is present in glands that allows them to secrete mucus, and where are these located in the gland?
There are lots of goblet cells on the surface and in the neck of the gland
What is present in glands that allows them to secrete acid, and where are these located in the gland?
There are parietal cells deep in the gland which secrete HCl