Glands and Cells of the Stomach.
Compared to gastric glands, how do the ducts of cardiac glands appear under H&E stain and what is the cause of this difference?
Cardiac glands have a twisted duct and so their appearance will not be linear as would a gastric gland. Cardiac glands also primarily secrete mucus, and will therefore be much more eosinophilic.
What type of cell secretes Pepsinogen, how is this zymogen activated, and what is the function of its active form?
Cheif cells, also called Peptic cells, secrete pepsinogen. Pepsinogen is activated into Pepsin by the acidic conditions found in the stomach. Pepsin functions to breakdown large proteins into smaller peptides so that they can be further processed in the intestine.
What cell secretes Rennin, also called Chymosin, and what is the function of this enzyme?
Chief Cells. They actually secrete zymogen forms of pepsin and chymosin/rennin which is activated by gastric acids.
What type of cells secrete Gastric Lipase and what is the function of this enzyme?
Chief cells secrete Gastric Lipase which functions to break down fats into smaller fatty acids that can be further digested in the intestine.
What substances are secreted by chief cells that aid in the digestion of food stuffs in the stomach?
Chief cells secrete: Pepsinogen: Coverted to Pepsin. Prochymosin: Converted to chymosin, also called rennin. Gastric Lipase: Secreted in active form.
Where are chief cells found in the mucosa layer and what is another common name for these cells?
Chief cells, also known as Peptic Cells, are found in the glandular region of gastric glands which is found in the lamina propria of mucosa layer.
What type of connective tissue is found in the Submucosal layer?
Dense connective tissue
What is unique about Enteroendocrine cells and their secretions when compared to the rest of the cells in a gastric gland?
Enteroendocrine cells, also called G-cells, secrete gastrin into the vasculature and not the glandular lumen as the rest of the secratory cells of the gastric gland do.
True or False. Parietal Cells are only located within the fundus of the gastric glands.
False. Parietal cells are located throughout the galndular region of the gastric glands.
True or False. Rennin is secreted in its active form via chief cells and functions to breakdown proteins found in milk.
False. Rennin does function to breakdown milk proteins, but is secreted by chief cells in its inactive form, Prochymosin.
What are G-cells, where are they found, and what do they secrete?
G-cells are also called Enteroendocrine cells, and they are found in the fundus of the gastric glands and pyloric glands. These cells secrete gastrin into the blood.
What is the function of Gastrin?
Gastrin is a hormone that stimulates increased secretions from parietal cells and increases GI motility.
In a gastric gland, what type of cell secretes an acidic mucin?
Mucus Neck Cells.
What cells of the stomach secrete HCl and where are these cells located?
Parietal cells secrete HCl and are located in the gastic glands.
What cell secretes Intrinsic Factor and what is the functional purpose of this secretion?
Parietal cells secrete intrinsic factor and it functions as a carrier molecule which binds vitamin B12 so that it can be absorbed by the intestine.
What do parietal cells secrete and what are the functions of these secretions?
Parietal cells secrete: Hydrochloric Acid: Serves to kill bacteria, activate enzymes, and to begin to breakdown chemical bonds of ingested food. Intrinsic Factor: Serves as a carrier molecule that binds vitamin B12 so that it can be absorbed by the intestine.
Parietal cells primarily secrete acid and a molecule called intrinsic factor, a glycoprotein, how would you expect this cell to appear in H&E?
Parietal cells will appear deeply pink color with a ceneterd basophilic nucleus. large amount of mitochondria and the carbohydrate chains of intrinsic factor yeild an eosinophilic appearance.
Given that Chief cells primariy secrete enzymes, how would you expect them to appear in a H&E stain?
Proteins, of which enzymes are made, stain heavily basophilic. Chief cells will therefore appear purple in H&E.
Compared to gastric glands, how do the ducts of pyloric glands appear under H&E stain and what is the cause of this difference?
Pyloric ducts are coiled and will appear to be more chaotic than a gastric gland, but not as chaotic as a cardiac gland. Pyloric glands secrete primarily mucus, and so appear eosinophilic when compared to gastic glands.
In a gastric gland, what type of cell secretes an alkaline mucin?
Surface Mucus Cells
What do Surface mucus cells secrete and what function does this secretion serve?
Surface mucus cells secrete alkaline mucus that functions to protect the glad from acidic conditions found in the stomach.
Where in the gastric glands are chief cells found?
Within the fundus.
