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67 terms

Histo Test 1

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Which parts of the oral cavity are keratinized stratified squamous epithelium?
gingiva, hard palate, dorsal surface of tongue
Which papillae are all over the tongue & do not have taste buds?
filiform papillae
Which papillae have taste buds laterally?
foliate papillae
Which papillae are between filiform?
fungiform
What taste dominates for circumvillate papillae?
bitter
What do ameloblasts secrete & what do odontoblasts secrete? where are they found?
enamel

dentin

tooth
3 Major salivary glands & what type of gland are they?
Sublingual - predominant mucous
Submandibular - mixed
Parotid - serous
Acinus?
area where secretion is produced
Where is serrous usually found?
periphery; serous demilune
Ducts of major salivary glands:
Intercalated duct - secrete bicarbonate, absorb Cl- from acinar product

Striated duct - reabsorption of Na ion from primary secretion, addition of potassium to secretion

Excretory interlobular duct - final duct
What parts of esophagus have what types of muscularis externa? Where are adventitia & serosa layers found?
Upper - striated muscle
middle - striated & smooth
lower - smooth muscle

adventitia - upper & middle
serosa - lower
What is an important part of the esophagus for disease (such as Barrett's esophagus? Why?
esophago/gastric junction; dramatic change of epithelium from stratified squamous --> columnar
Where are Brunner's glands found?
Duodenum
Where are peyer's patches found?
ileum
What part of intestines no longer have villi?
colon
What are the 2 types of plexi & where are they found?
Meissner's plexus - submucosal
Auerbach's plexus - myenteric
Why are so many mucus glands found in esophago-gastric junction?
for acidity of stomach to be neutralized
What 2 things protect the squamous epithelium of esophagus from exposure to gastric acid?
esophago-gastric junction & esophago-gastric muscular sphincter
What can heartburn (reflux of gastric acid into lower esophagus) lead to?
changes of stratified squamous epithelium to gastric epithelium (columnar)
What is the importance of Rugae?
allows the stomach to distend
cells of gastric gland epithelium?
-mucous neck cells (soluble mucus)
-parietal cells (HCl)
-chief cells (pepsinogen)
-Enteroendocrine cells (hormones)
-stem cells
How can a gastric ulcer form?
helicobacter pylori infection can damage stomach mucosa's protective layer, acidic gastric content damages mucosa epithelial cells/lamina propria die -->ulcer
How can a gastric ulcer cause death?
ulcer can perforate stomach wall & gastric contents can pour into peritoneal cavity
Where will you see parietal cells?
starting at isthmus
Where are chief cells found?
lower part of gland
Which gastric gland cell has endocrine function?
enteroendocrine cell (imp. in GI regulation)
How can atrophic gastritis lead to pernicious anemia?
lack of parietal cells so lack of intrinsic factor (needed to absorb B12)
Which cells protect stomach's epithelium?
surface mucous cells
How many layers are there of gastric muscularis externa?
3
Where are the tallest/greatest number of villi found bc more absorption?
jejunum
What are the structures responsible for the small intestine's increased surface area?
1. plicae circulares (folds of submucosa)
2. villi (folds of mucosa)
3. crypts of lieberkuhn (glands)
4. microvilli w/ glycocalyx
Where is the abundance of plicae circulares?
distal part of duodenum & jejunum
Enterocyte?
absorptive cell w/ microvilli (brush border) found near top of villus in small intestine
Paneth cells?
contain lysozyme & are found in crypts of small intestine
Celiac disease?
allergic to gluten - leads to flattening of jejunal surface or loss of villi
-can reverse
Where are brunner's glands found & what do they do?
duodenum - neutralize acidity of stomach
What plays a role in transport of antigens from lumen into lamina propria?
Peyer's patches
Where do you find M cells?
microfold cells are found in small intestine & large intestine
Which cells secrete mucin? where are they found?
goblet cells - ileum
In the large intestine, do surface cells have glycocalyx & digestive enzymes?
no digestive enzymes but still glycocalyx
Taeniae coli?
added layer of muscularis externa
Where are goblet cells found in highest concentration?
rectum
What is large intestine lacking from rest?
villi & folds & lacteal
What is specifically found in large intestine & oral cavity?
large number of bacteria
Ulcerative colitis
mucosa is lost w/ ulceration & destruction of absorptive epithelium impairing water resorption from colonic contents resulting in watery diarrhea & bleeding
Hirschsprung's disease (congenital megacolon)
defecation is not possible; infants & children; segment of lower rectum is devoid of ganglion cells
Where is appendix & what types of cells does its epithelium have?
bw large & small intestine

absorptive cells & M cells
Other than esophagus to gut, where else is abrupt change in epithelium?
rectum -> anal canal (simple columnar -> stratified squamous)
Where do ducts open w/ pancreatic & liver secretions?
duodenum
If you are missing this in colon, you would have megacolon?
plexi
In the liver, what does it mean if you have a lot of connective tissue?
liver damage
sources of blood -> liver?
portal vein - 75%
hepatic artery - 25%
in hepatic circulation, where does blood go toward?
central vein
Function of hepatocytes?
endocrine secretion
-storage of lysosomes
-degradation of toxins
Where are hepatic stellate cells? What is it a storage site for?
in space of disse - bw endothelial cells & microvilli of hepatocyte

vitamin A

aka ito cells
Where are kupffer cells? Main function?
in sinusoids

phagocytic
Where are reticular fibers in liver?
walls of sinusoids
What can happen w/ ito cells?
transform to myofibroblasts & produce high level of collagen
-collagen type 1 (cytokines produces by hepatocytes stimulate production) deposited in space of Disse leads to fibrosis & alteration of portal venous blood flow (portal hypertension)
Endocrine vs. exocrine liver
endo - secretion into sinusoids
exo - secretion into bile canaliculi
How does liver cirrhosis occur?
progressive hepatocyte destruction due to alcohol toxicity, viral infection & liver disease
-death of hepatocytes -> scarring
-collapse of normal architecture & increased production of fibrocollagenous tissue
(massive collagen production)
What are 3 ways of describing structure of liver? Most clinically important?
1. classic lobule - hexagonal, axis = central vein
2. portal lobule - triangular, axis = interlobular bile duct
3. liver acinus - eleptical, axis = distributing vessels

-liver acinus most clinically imp. bc looks at blood flow to liver
zones of liver acinus:
zone 1 - first to receive nutrients or toxins (most O2)
2 - between
3 - last to receive nutrients & toxins (most affected if O2 decreases)
Major functions of gallbladder?
concentrates & stores bile (stored by taking H20 away), absorption of water & electrolytes
What can be caused by large gallstones?
-obstructive jaundice - obstruction of bile duct
-cholecystitis - obstruction of cystic duct
Pancreas function?
endocrine & exocrine function (can't condense like liver)
What 2 hormones are under control of exocrine function by enteroendocrine cells in duodenum?
seretin - stimulates biocarbonate ion secretion
CCK - stimulates enzyme secretion
What 3 cells are found in endocrine pancreas & what do they secrete?
B cells - insulin
A cells - glucagon
D cells - somatostatin