GI system: L24 - Stomach and pancreas Flashcards
Name the specialised regions of the stomach.
Fundus, body, pylorus, pyloric sphincter.
What structure in the stomach allows storage?
The inside of the stomach has a folded surface that allows it to expand and increase in volume without increased pressure. The folds are known as rugae.
Location of the stomach is?
Upper part of abdominal cavity, below the liver and diaphragm.
Name the curvatures of the stomach.
The right curvature is the lesser curvature, the left curvature is the greater curvature.
Describe the structural components of the stomach wall.
Serosa - supporting connective tissue.
Muscularis - outer longitudinal, middle circular, inner oblique layer to provide contractility in all directions.
Submucosa and mucosa are folded for the rugae, gastric glands extend from the level of muscularis mucosae to open into the lumen of the stomach via gastric pits. The final layer is simple columnar epithelia which are highly invaginated.
What are mucous cells for? Where are they located?
Produce mucous at the surface of the epithelium to protect it from the chemicals present in the stomach and from abrasion of stomach contents. They are found on the luminal surface of the stomach as well as gastric pits and gastric glands.
What are chief cells for and where are they located?
Found in gastric glands, secrete enzymes including pepsinogen that help with chemical digestion of proteins.
What are parietal cells for and where are they located.
Found towards the base of gastric glands. Produce gastric acid which help activate pepsinogen.
What are neuroendocrine cells for and where are they located?
Found in the base of gastric glands, secrete hormones such as gastrin.
Describe the location of the pancreas.
Tail of pancreas touches the spleen. Pancreas is posterior to stomach. The head of the pancreas lies in the ‘C’ part of the duodenum.
Describe the transport of exocrine products from pancreas to small intestine.
Exocrine products released from the pancreas travel down the pancreatic duct. The common bile duct and the pancreatic duct meet at the Hepatopancreatic ampulla at the ‘greater duodenal papilla’.
Secretions from the liver, gallbladder and pancreas enter the duodenum by passing through the ‘sphincter of Oddi’, a muscular valve that controls their flow from the ampulla into the duodenum.
Describe the endocrine function of the pancreas.
Pancreatic islets contain beta cells (insulin) and alpha cells (glucagon) which secrete their respective hormones.
Explain the structure and exocrine function of the pancreas.
The exocrine portions of the pancreas are the acini (group of secretory cells) of spherically clustered acinar cells surrounding the pancreatic duct. These acinar cells secrete digestive enzymes and duct cells produce bicarbonate to neutralise acid so that the enzymes work.
What structures would we observe looking at a singular acinus cell using transmission electron microscopes? How does this relate to function?
Lots of Rough endoplasmic reticulum to make proteins. Also lots of zymogen granules (inactive digestive enzymes).
