histo part2 Flashcards
What kind of epithelium does the stomach have?
simple columnar epithelium
What does the lamina propria of the stomach contain?
GLANDS! Gastric, pyloric, cardiac
Also cells! Mast cells, plasma cells, white blood cells, smooth muscle cells, small blood vessels, diffuse lymphatic tissue
What does the submucosa of the stomach contain?
loose CT, larger blood vessels, lymphs and autonomic nerve plexi
What layers of the muscarlis externa thicken to form the pyloric sphincter?
innter and middle
Where is the myenteric nerve plexi
bwtn the middle and outer layers of the muscuarlis externa
The surface region of the body and fundus extend into the lamina propria to form what
gastric pits, 2-4 glands open at the bottom of each put
What is the entrance of the glandular region called? what happens there>
ishmus, germinative zone-cells are renewed,
Where is the most mitotic region in the musocsa of the body and fundus?
NECK!also has musuc secreting musocsa neck cells and parietal cells
The cells of the gastric or fundic glands do what and are what?
secrete acid and enzymes of the stomach, parietal cells, chief cells (zymogenic), enteroendrocrine cells
What kind of cells are the mucous neck cells? what do they do?
cuboidal to low columnar in shape and secrete mucous to protect against HCL and enzymes
Where are parietal cells most numerous?
in the neck and upper portion of the body glands
What are parietal cells characterized by?
numberous mitochondria and canaliculi, eosinopgilic
What does the parietal cell secrete?
intrinsic factor (necesseary for B12 absorption) from the ilium and HCL
What activates a parietal cell?
cholingeric nerve endings, gastrin and histamine
Where are cheif cells/zymogenic cells most numberous?
basal region of gland
What does the chief cell secrete?
pepsinogen, whichis converted to pepsin in the presence of HCL
What does pepsin do?
conteres proteins to peptides
Enteroendorcine cells (DNES) secrete what? and where?
hormone or hormone like products into the lamina propria or the vascular system
A-stomach Produces what and action?
glucagon- hepatic glycogenolysis
G-pyloris produces what and action?
gastin- stimulates gastrin acid secretion
S-small intenstine produces what and action?
secretin- pancreatic and biliary bicab and water secretion
K-small intestine hormone and action?
GIP- inhibits gastin acid secretion
L small intestine secretions what and does what
glucagon like substance (glicentin), hepatic glycogenolysis
I small intestine secretes what and action
CCK, pancreatic enzyme secretion, gallbladder contraction
D-pyloris and duodenum secrets what and does what
somatostain- inhibits other endoricne cells
Mo small intestine
Motillin, increases gut motility
EC- digestive tract
seratonin, substance P- increase gut motility
D1 digestive tract
VIP, ion and water secretion, increased gut motility
Some features of the glandular region of the pyloric region
Simple columnar epithelium
Simple, branched, coiled tubular glands extend from bottom of gastric pit to muscularis mucosae
Cells are mucous cells similar to mucous neck cells
Different bwtn the cardiac region and pyloric region?
gastric pits of the cardiac region are only 1/4 thickness of the muscosa
Functions of the stomach? (4)
Mixes food to produce chyme
Begins digestion process
Produces intrinsic factor for absorption of vitamin B12 (extrinsic factor) from ileum
Some absorption (but not much)
Functions of the small intenstine?
Complete digestion of food
Absorb final products of digestion
Whera re the plicae ciculares found?
Duodenum and upper jejum, NOT IN THE ILEUM, may increase the surface area by a factor of 3
Whats the most characteristic feature of the small intestine
VILLI, formed by the musocsal lining, also has distinct muscarlis mucosa and plicae circulares
the submucosa of the small intestine contains what
core of plicae cicularies, large blood vessels, lymph cells and submucosa nerve plexi with post gang cell bodies
The muscularis of the SI is made up of what
two layers of smooth muscle(Inner circular layer
Outer longitudinal layer), myenteric nerve plexus bwtn them,
Serosa is present everywhere except?
areas which are retro-peritoneal like parts of the duodemun
The villus epitheloum of the SI contains what?
villus epithlium (simple columnar), absorptive cells, goblet cells, enteroendorcine cells,
The crypt epithelium on the Si contains what?
simple columnar epithelium with Absorptive columnar cells Goblet cells Enteroendocrine cells Paneth cells Undifferentiated cells (stem cells)
What does the lamina propria of the SI do?
CT core around each villus, has a lacteal, capilarries and venules present and lots of cells!
What is a characteristic feature of intestinal crypts?
they extend into the lumen of the SI, the muscarlis mucosa does not extent into the vilus
The crypts of lieberkuhn (intestinal glands), characteristics?
open at base of vili, extend into the muscarlis mucosa, paneth cells at the base of crypts
Characterics feautures of absoprtive columnar cells?
numberious microvilli on the free srface, brush boarder contains enzymes which help with giestion and sbroption
Characterics of goblet cells?
muscus secretiing cells, the increase from the duodenum to the colon
Characteristics of the enteroendrocine cells?
found adjacent to the BM, secrete hormones
Characteristics of paneth cells?
found at the base of crypts, red or pink granules, has lysozyme, maybe helps regulate intestinal bacteria
characteristics of undifferentiated cells?
free ribosomes, source of intestnial carcinoma
Where are brunners glands? what do they do?
duodenum in the submucosa and lamina propria, secrete alkaline mucus to neutralize acid from the stomach,
Peyers patches are found where? and are?
ileum, lympathic nodules that secrete IgA
What cells are located above the peyers patches? purpose?
M cells- endocytose antigen and transport it into lymph tissue
What is the important of tight junctions of intestinal epithelium?
compartmentalizes membrane proteins, requires materials to be absorbed first to enter the absoprtive cell
