Histology Flashcards
What are the layers of the GI tract?
Mucosa
- Epithelium
- Lamina Propria
- Muscualris mucosae
Submucosa
Muscularis externa
Serosa/Adventita
(M,S,M,S)
And ELM tree
Where is the GALT found?
Lamina propria
Where is the submucosa plexus found?
Submucosa
Where is the myenteric plexus found?
Muscularis externa
What epithelium covers the oral cavity, oropharynx, laryngopharynx and tongue?
Stratified squamous epi
What epithelium covers the nasal cavity and nasopharynx?
Resp epi
What papillae have no taste buds?
Filiform
Name the 4 tonsils
Pharyngeal
Palatine
Lingual
Tubal
What is the change in epithelium at the gastro-oesphageal junction?
Change from stratified squamous epi -> simple columnar epi
What is the structure of the stomach mucosa
Gastric pits and glands
Superior - gastric pit
ISTHMUS
Inferior - gastric pit
What is the function of parietal cells?
To produce HCl
What is the function of chief cells?
To produce digestive enzymes
What is the function of stem cells?
To produce new cells
What is the function of the enteroendocrine cells?
Produce hormones to control secretions and motility
What is special about the muscularis externa of the stomach
Contains an oblique layer underneath the circular layer
From deep to superfical
Oblique
circular
Longitudinal
What makes the gastroduodenal junction?
Pyloric sphincter
What is the structure of the small intestine mucosa?
Villi and Crypts of Lieberkuhn
What are enterocytes?
Absorptive intestinal cells
What are goblet cells?
Mucus producing cells
What are paneth cells?
Cells that produce antibacterial properties
What region of the small intestine has plicae circularis?
Describe mucosal changes from jejunum to ileum
Jejunum
Jejunum has plicae circularis (folds) gets increasingly smoother as you reach distal ileum
What region of the small intestine has Peyer’s Patches?
Ileum - aggregates of lymphoid tissue
What region of the small intestine has Brunner’s Glands and what are they?
Duodenum - glands which secrete alkaline fluid to buffer the highly acidic chyme coming from the stomach
What is the structure of the large intestine mucosa?
Crypts but no villi (still microvilli/brush border
What are the 2 main cell types of the large intestine?
Enterocytes
Goblet cells
What are the teniae coli?
3 bands of longitudinal muscle which run from caceum to sigmoid colon
What is present in large amounts in the appendix?
Lymphoid tissue
What is at the centre of a liver lobule?
Central vein
What are at the corners of a liver lobule?
Portal triad
What are the main cells of the liver?
Hepatocytes
What travels through the sinusoids and where does it go?
Blood from hepatic artery and portal vein and runs through sinusoid being “cleaned” into the central vein
What are Kuppffer cells?
Macrophages found in the sinusoids
What is the name for the space between sinusoid and hepatocyte called?
Space of Disse
What type of cells can be found in the Space of Disse?
Hepatic stellate cells - fibroblasts (can create scar tissue when liver undergoes damage)
What are the 3 blood vessels supplying/draining the liver?
Hepatic artery
Hepatic vein (flow into IVC)
Portal vein
What is the opening at the hilum of the liver called?
Porta hepatis
What 3 vessels make up the portal triad?
Hepatic artery
Portal vein
Bile duct
What cells produce bile?
Hepatocytes
What is the function of bile
To emulsify fats
What is the function of the gallbladder
To concentrate and store bile
What nerve stimulates contraction of the gallbladder?
Vagus nerve
What hormone stimulates contraction of the gallbladder?
CCK
What epi can be found in the gallbladder?
Simple columnar epi
What is the function of the exocrine pancreas?
To produce digestive enzymes
What are the secretory/functional cells of the pancreas?
Acinar cells
What is the function of the zymogen granules?
Organelle responsible for
Sorting, packaging and regulation of secretion of digestive enzymes
Are the enzymes produced activated or inactivated?
Inactivated become activated in the duodenum
What is the name for the cells of the intercalated duct that extend into the acinus?
Centroacinar cells
What is the name for the pacemaker cells of the GI tract and where are they found?
Intersital cells of Cajal - in plexus connected to smooth muscle
Name the 2 plexuses found in the GI tract and state their location
Myentric plexus - muscularsis externa
Submucosal plexus - submucosa
