Histology of GI Flashcards
Three types of glands found in the stomach
Pyloric, cardiac and fundic/ gastric
Which layer of the stomach are gastric pits founds
Mucus layer
Three characteristics of gastric pits
Found in mucosa, lined by surface mucous cells and have gastric glands an their base
Which type of glands in the stomach has narrow lumen and shallow pits
Fundic glands
Which glands in the stomach have wide lumens and deep pits
Pyloric and cardiac glands
What do surface mucous cells in gastric pits secrete
Insoluble, viscous, gel-like coating that is rich in bicarbonate ions
Five cell types in the fundic gland epithelium
Mucus neck cells Parietal/oxyntic cells Chief/peptic cells Enteroendocrine cells Stem cells
Which fundic epithelial cell type produces SOLUBLE low-alkaline secretions
Mucus neck ells
Which fundic epithelial cell type has the longest life span
Parietal cells
Which fudic epithelial cell type is acidophilic and why
Parietal/oxyntic cells because they have a lot of mitochondria
Why do parietal cells have a lot of mitochondria
ATP is needed for proton pumping
Which fundic epithelial cell type has canniculi and many micro villi
Parietal/oxyntic cells
Damage to which fundic epithelial cell type causes pernicious anemia
Parietal cells
How is pernicous anemia caused
If parietal cells are damaged they cannot make intrinsic factor which is need for vitamin B12 absorption. Vit B12 is needed for DNA synthesis in erythrocytes
How is Achlorhydria (no acid production)
Damage to parietal cells
How can Achlorhydria also affect protein digestion?
Pepsinogen (secreted form chief cells) need to come into contact with acid to be cleaved into its active form, pepsin
Which fundic epithelial cell produces pepsinogen
Chief/peptic cells
Which fundic epithelial cells are basophilic
Chief/peptic cells because they have a lot of proteins (and RER)
How is pepsinogen activated
Pepsinogen is converted to pepsin when it comes into contact with acid gastric juice
Which side of chief cells contain the enzyme precursors
Apical surface
What type of epithelium is in the esohagus
non keratinized, stratified squamous
What type of epithelium is in the stomach
simple columnar
Three components of the gastric mucosal barrier
Viscid mucus from surface cells
Bicarbonate ions from epithelial cells
Tight junction
The absorptive surface of the small intestines is increased by
Circular folds (plicae circulares)
Villi
Microvilli
What kind of glands extend form the muscularis mucosae to open into the lumen of villi
Simple tubular intestinal glands (crypts of Lieberkühn)
Function of enterocytes
Absorptive cells that transport substances from the lumen of the small intestines to the blood or lumphatics
Function of goblet cells
Secrete mucin
Function of paneth cells
Have antimicrobial activity (eg. lysozome or apha defensins) and are found in the base of the intestinal glands
Function of enterendocrine cells
Secretion of endocrine and paracrine hormones
Function of M cells
Antigen transporting cells that cover lymphatic nodules
Six types of ells lining the crypts of the intestines
Enterocytes, goblet, paneth,
enteroendocrine, stem and M cells
What are Payer’s patches
Aggregations of lymphatic nodules that contain B and T cells
Which structures are a part of the GALT in the small intestines
Payer’s patches and M cells
What structure in the large intestines condenses to form teniae coli
Muscularis externa
Which structure in the large intestines is associated with maturation of immune cells during early life
Appendix
Which artery supplies the liver
Hepatic artery
Which vein supplies the liver
Hepatic portal vein
Structural components of the liver
Parenchyma, sinusoidal capillaries and Connective tissue stroma
What is paranchyma
Plates of hepatocytes
What are sinusoidal cappillaries
They separate plates of parenchyma
What do hepatocytes consist of
Lots of golgi and rough ER- protein sythesis
Numerous mitochondria
Smooth ER- synthesis of lipids and detoxification of bilirubin
Many peroxisomes- detoxification of various toxins
Deposits of glycogen
Lipid droplets
What are the different types of surfaces on a hepatocyte
Sinusoidal surface and a lateral & canalicular surface
Describe the sinusoidal surface of hepatocytes
It faces the parasinusoidal space and has many micro villi that open into the space
Describe the later& canalicular surface of hepatocytes
It faces the neighboring hepatocytes and had bile canaliculus that is sealed by a tight junction
