Week 4 - Functions Of Stomach Flashcards
what does the stomach digest?
Mainly proteins
What are the sections of the stomach and roughly where are they?
Cardia - near heart, by lower esophageal sphincter
Fundus - at the top
Body - main part
Antrim - lower section after curve
What marks the exit of the stomach?
Pylorus
Where i the angular is located?
On the lesser curve
What is the epithelium of the esophagus?
Stratified squamous
What is the epithelium of the stomach?
Simple columnar
Why has the epithelium changed from esophagus to stomach?
For secretion
What are the little holes visible in the stomach?
Gastric pits
What types of cells are found in the gastric pits?
Mucous cells
Parietal cells
Chief cells
G cells
What is the important feature of smooth muscle in the stomach?
Has an extra oblique layer allowing to mix and grind contents more effectivly
What is the importance of sustained contraction in the upper stomach?
Creates basal tone which reduces reflux
How does the stomach pass food along?
Coordinated contractions proximal to distal
Contents accelerate to smaller end
Separates contents - lumps left behind
Liquid chyme ejected into duodenum
Why do we need rugae?
We eat faster than we digest so we need a store of food
Rugae give stomach ability to distend
what is perceptive relaxation?
Vagally mediated relaxation of road stomach
What is the importance of perceptive relaxation?
Allows food to enter stomach without raising intra-gastric pressure too much, prevents reflux of stomach contents during swallowing
What is the road stomach?
The top half of stomach
Why do we need the stomach to be acidic?
Helps unravel proteins
Activates pro teases
Disinfects stomach contents
What does the stomach secrete?
HCl
Intrinsic factor
Mucous/bicarbonate
Pepsinogen
What is intrinsic factor?
A glycoproteins that enables absorption of vitamin B12
What do parietal cells secrete?
HCl and intrinsic factor
What cells secrete gastric?
G cells
What is the function of gastrin?
Peptide hormone that stimulates secretion of HCl
What do enterochromaffin like (ECL) cells secrete?
Histamine
What cells secrete pepsinogen?
Chief cells
What do D cells secrete?
Somatostatin
What is somatostatin?
A hormone secreted by pancreas and pituitary gland which inhibits gastric HCl secretion and somatotropin release
What cells secrete mucous?
Mucous cells
What cells are found in the cardia of the stomach?
Predominantly mucous cells
What is secreted in the fundus/body of the stomach?
Mucous
HCl
Pepsinogen
What is secreted in the pylorus?
Gastrin
Somatostatin
What stimulates HCl secretion from parietal cells?
Gastrin
Histamine
ACh
Where is gastrin produced?
Pyloric antrum of stomach
Duodenum
Pancreas
What is the main stimulant of HCl and how does it work?
Gastrin released into blood stream and acts on enteroendocrine cells which release CCK which stimulates release of HCl from parietal cells
