Histology Flashcards
What type of cell lines the oral cavity?
non-keritinized stratified squamous epithelium
What type of cell lines the nasal cavity and nasopharynx?
respiratory epithelium
What type of cell lines the anterior 2/3rd of the tongue?
stratified squamous epithelium
- thin on ventral side
- thick with papillae on the dorsal side
What type of cell lines the posterior 1/3rd of the tongue?
smooth stratified squamous epithelium with no papillae but has lymphoid aggregates in the submucosa
What are the four types of papillae?
fungiform
circumvallate
foliate
filiform
What is at the entrance to the oropharynx?
ring of lymphoid tissue with the palatine, lingual, tubal and pharyngeal tonsils
What type of muscle is in the oesophagus?
- upper is skeletal
- middle is both
- lower is smooth
What lubricates the oesophagus?
mucous glands in the submucosa
What type of cell is in the stomach?
simple columnar epithelium
with gastric pits and 1-7 glands at the bottom of each
What cells line the cells of the gland?
- the neck= neck mucous cells and parietal cells which make HCl
- the isthmus= parietal and stem cells
- the fundus/base= chief cells that produce enzymes and some enteroendocrine cells
How can the parietal and chief cells be identified?
parietal looks like pink fried eggs
chief looks dark and grainy
What are the sections of the stomach called?
- Cardia: deep gastric pits and tortuous glands
- Body: shallow gastric pits and straight glands
- Pylorus: deep pits and many coiled glands
What is the extra layer of muscle that the stomach has?
musculares externa is an oblique layer that is internal to the circular layer and churns
Where is the pyloric sphincter?
between stomach and duodenum so gasproduodenal junction
What is an extra feature of the small intestine?
villi with crypts of Lieberkuhn in between
What are the differences in cells in the different parts of the small intestine?
- Duodenum: Brunner’s gland in submucosa to neutralise chyme
- Jejunum: tallest villi
- Ileum: many lymphoid follicles called Peyer’s patches
What are the cells and a brief role of each in the small intestine?
- Enterocytes: tall columnar with brush border
- Goblet: mucin producers for lubrication
- Paneth: defense
- Enteroendocrine: hormone production for motility
- Stem: base of crypts to replenish epithelium
What are the two types of cells of the large intestine?
- Absorptive: removal of salts and water
- Goblet: secretion of mucous
What is the name for the three muscular strips down the side of the large intestine?
teniae coli
How does the appendix tissue differ?
less crypts and circular lymphoid tissue
What cells line the anal canal?
stratified squamous epithelium that becomes keratinized later on at skin level
What is the ENS made up of?
two plexuses of nerve fibres- one in submucosa (submucosal), one in the muscularis externa (myenteric)
What is a ganglion?
a group of nerve cells living outside of CNS
What is the basic structure of the liver?
- covered with mesothelial cells
- lobules with a central vein in the middle and the hepatic artery, portal veins and the bile duct supplying the ends (portal triads)
- blood enters at the ends and leaves in the middle
What makes up the triad of vessels in the liver?
1 - bile duct: lined by simple cuboidal cells called cholangiocytes
2 - hepatic portal vein: large thin walled blood vessel
3 - hepatic artery: round vessel with smooth muscle (sometimes a lymphatic vessel too)
What is the relationship between hepatocytes and liver sinusoids?
- hepatocytes form plates or sheets of cells with spaces for blood to flow called sinusoids
- lining between these two structures (simple squamous lining)
- space is called the space of Disse
- connective tissue in the liver in the portal tracts as well as collagen in the space of Disse
What is the role of hepatic stellate cells and where are they found?
found in the space of Disse
- make connective tissue
- store vitamin A in fat droplets
- become myofibroblasts and become scar tissue in cirrhosis
What are Kupferr cells are where are they found?
sinusoids in the liver and they are macrophages to remove dead matter
Where does bile go after being made?
- made in liver by hepatocytes
- taken to bile ductules via bile canaliculi
- to gallbladder
What are bile caniculi?
small channels formed by tight junctions between hepatocytes where bile moves to bile duct
What is the gallbladder made up of?
muscular sac lined with tall simple columnar epithelium with lamina propria and brush border
How is bile changed in the gallbladder and how is it then released?
- changed by pumping Na and Cl ions so water moves out too
- vagal stimulation to contract to release bile into duodenum and by cholecystokinin
What is the special feature of the pancreas?
it is both an endocrine and an exocrine gland
What does the exocrine part of the pancreas do?
makes digestive juices with many enzymes and this enters the duodenum via the pancreatic duct (doesn’t digest itself because the enzymes are not yet active until trypsin activates them)
What does the endocrine part of the pancreas do?
consists of islets of Langerhans making insulin and glucagon
What are the different parts of the pancreatic ducts?
basal pancreatic part is basophilic due to RER but apical part is eosinophilic due to zymogen granules
What do the pancreatic ducts then join?
main pancreatic duct joins the common bile duct and opens into the duodenum on a papillae
What is special about pancreatic duct cells?
they are centroacinar because the duct Strats within the cell
