GIT Histology Flashcards
What are the components of the enteric nervous system?
Sensory neurones
Motor neurones
Interneurones
What class of cells are in the anal mucosa?
Stratified squamous
What do paneth cell secrete?
Anti-microbial peptides
Are sinusoids derived from hepatic arteries or portal veins?
Both
Do hepatocytes have microvilli?
Yes
How is the portal lobule model defined?
By the direction of bile flow - towards the hepatic triads
What is contained in the lamina propria?
CT
Nerves
Small vessels
Immune cells
What is the direction of the 3rd layer of muscle in the stomach?
Oblique - changes over the course of the stomach
Name 5 functions of the liver
Absorption of fat
Production of proteins
Detoxification
Metabolism
Storage
What does the liver store?
Iron
Some vitamins
Glycogen
Glucose
What the capillaries of the liver called?
Sinusoids
How are lobules divided?
They are defined by their blood supply
Which part of pancreatic cells is darker?
Basal
What is the function of the central vein?
Drain blood from the sinusoids into the hepatic veins
What makes the basal region of pancreatic cells darker?
Rough ER
What does the rough ER of hepatocytes do?
Protein synthesis
What distinctive features does the ileum have?
Peyer’s patches
Short villi
Lots of goblet cells
What class of cells are in the gall bladder?
Simple columnar absorptive
What is the connective tissue of the liver called?
Stroma
What do the Islets of Langerhan produce?
Insulin and glucagon
What are the layers of the mucosa?
Epithelium
Lamina propria
Muscularis mucosae
What is contained in the submucosa?
Vessels
Nerves
Small ganglia
Sometimes: Immune cells
Glands
How do sinusoids differ from capillaries?
Larger
Have discontinuations in their endothelium
What are macrophages that interface with hepatocytes called?
Kupfer cells
What is the functions of enterocytes?
Fluid transport/absorption
What are the common layers of the GIT?
Mucosa
Submucosa
Muscularis externa
Serosa/adventitia
What is the structure of pancreatic acini?
Ball of cells around a central duct
Where in the GIT are enterocytes found?
Small intestine
Colon
Appendix
Where are the neuronal components for controlling smooth muscle activity?
Myenteric ganglia
What is the name of the connective tissue that surrounds hepatocytes?
Reticular fibres
What is exceptional about hepatocytes?
They can have multiple nuclei
They have prominant smooth and rough ERs
They have many mitochondria
What is the lifespan of a hepatocyte?
150 days
What does the smooth ER of the liver do?
Fat and steroid metabolism
T/F The jejunum has Peyer’s patches?
False, they don’t yo
Why are their striated muscle cells in the upper oesophageal muscularis externa?
Because swallowing has corticol control
What is the name of the sphincter at the major duodenal papilla?
The sphincter of Oddi
What percentage of the pancreas is endocrine?
1-2%
What direction due muscle fibres of the muscularis externa lie?
Circumferential on the inner layer
Longitudinal on the outside
What is the function of the gall bladder?
Store bile
Concentrate bile by removing water and salts
What determines whether the outer layer will be adventitia or serosa?
Adventitia is present where organs are connected to each other
Serosa is present where organs lie against each other
What are the three generations of folding in the small intestine?
Plica circulares
Villi
Microvilli
What do Brunner’s glands secrete?
Alkaline mucous to neutralised stomach acid and digestive enzymes
What do inter-neurones do?
Control the intrinsic reflexes
How can you tell a hepatic artery from a hepatic portal vein?
Hepatic arteries are more circular while hepatic portal veins have a thinner wall
T/F the large intestine is just the colon?
False, it includes in the rectum and anal canal
What is the name of the endocrine glands of the pancreas?
Islets of Langerhan
In terms of plica circulares and villi, how would you describe the duodenum?
Low plica circulares
Long villi
What is the main feature of secretory mucosa (eg stomach mucosa)
Long pits of glands
T/F Each portal triad supplies one lobule
False, each supplies many
What is the composition of blood in sinusoids?
80% deoxygenated
20% oxygenated
What makes the lumenal part of pancreatic cells lighter?
Zymogen granules of inactive enzymes
What class of cells is the serosa?
Simple squamous
What cause the gall bladder to contract and the sphincter of Oddi to relax?
CCK
How is the acinar lobule model defined?
By the relative amounts of O2 and metabolites - less towards the central vein
What are reticular fibres composed of?
Type I/III collagen
What are the channels that collect bile called?
Canaliculi
Cf to the small intestine, how many Paneth cells does the large intestine have?
It has less
What lies inbetween the muscle layers of the muscularis externa?
Myenteric ganglia (small ganglia)
What is the submosa?
Dense, irregular connective tissue
What is the function of the muscularis mucosae?
Facilitate mixing
What are the 4 cell types of the gastric pits? What do they secretion?
Mucous cells - mucous
Parietal cells - acid
Enteroendocrine cells - hormones (gastrin)
Chief cells - pro-enzymes (pepsinogen)
What class of cell make up the epithelium of the oesophagus?
Stratified squamous
The structure of Brunner’s glands could be described as …?
Very coiled
What are crypts?
Tubular glands in between villi
Approximately how big are the lobules of the liver?
0.7mm x 2mm
How is the classic lobule model defined?
By the direction of blood flow with the central vein in the middle
What is a space of Disse?
Discontinuation of endothelium of a sinusoid
What percentage of the products of digestion are absorbed in the small intestine?
85%
Given the contents of the large intestine is more solid, what types of cells does it have more of?
Goblet cells
What does the portal triad contain?
Hepatic portal vein
Hepatic artery
Bile duct
Lymphatic
How you can tell a bile duct from a vessel in the portal triads?
They have a simple columnar endothelium
