Histology Review: GI TRACT ONLY Flashcards
general structure for GI histology layers
- mucosa
- submucosa
- muscularis externa
- adventitia serosa
layers of mucosa
epithelium
lamina propria
muscularis mucosa
plexus in the submucosa
meissner’s
plexus in between the longitudinal muscle and the circular muscle
myenteric/ Auerbach’s
4 functions of GI tract in general
Motility
Secretion
Digestion
Absorption
functions of the mucosal layer
secretion
absorption
protection
function of submucosa
provide blood and lymph, nerves and occasional glands
Muscularis externa functions
inner-decreases lumen diameter
longitudinal-propels contents shortening the tube
*rhythmic contraction produces peristalsis
what forms the sphincters throughout the Gi tract
inner circular muscle
epithelium in the esophagus
NON keratinizing SS
*like vagina
mucous glands in esophagus lamina propria
cardiac
esophagus GALT located in
Mucosa
esophagus submucosa contains
tubuloalveolar glands
secrete mucous into ducts
upper 1/3 of esophaugus
vagal-ACH controlled skelatal muscle
Voluntary?
lower 2/3 of esophagus
Vagal? ACH? SMooth muscle?
involuntary
stomach makes
chyme
GERD caused by
dysfunctional LES
four regions of the stomach
- cardia
- fundus
- body-orad-oxyntic
- antrum-pyrlorus-caudad
functional features of stomach lining
- rugae that dissappear with distention
- gastirc pits
- gastric glands
stomach epithelium
simple columnar
- with goblet cells
- know Barret’s metaplasia
forms the core of rugae
submucosa
Muscularis externa of the stomach
- inner oblique
- middle circular
- outer longitudinal
pyloric sphincter located?
pyloro-duodenal junction
-made from circular layer
“surface mucin cells” secrete
alklaline mucin
*protective
describe the surface of the stomach
surface mucous cells invaginate into LP to create gastric pits
below gastric pits in the LP is
gastric glands
*continuation of
where are regenerative cells for glands found?
in the isthmus between pits and glands
cheif cells make
pepsinogen
cheif cells located where in gastric pit?
the very bottom (basal basophilia)
secretory granules of cheif cells are
acidophillic
pareital cells secrete
- HCL
2. Intrinsic factor (V b12 absorption)
parietal cells most neumerous….
in upper pat of GLAND
-below isthmus
enteroendocirine cells found at——-and produce——
all levels
variety or Hormones
shape/color of parietal cells
triangles
-acidophillic (eosinophillic)
cell division restricted to
isthmus-stem cells
*some more up and become surface mucous cells some move down to become glands
time frame for surface cell regen
3-5 days
time frame for chief cell regen
3 months
parietal cells live….
6 months
diff b/w mammillated folds and rugae
mamm folds-mucosa only
*rugae=mucosa and submucosa
H pylori trophic for which part of gastric glands
neck right below isthmus-in the stem cells
-accelerates proliferation of stem cells in neck during gastric carcinoma
major sight of absoprtion
jejunum
functions of Small intestines
mostly absorption also completion of digestion
increase SA x 3
plicae circulares
core of submucosa
-like rugae but permanent
Plicae circulares most common in
jejunum
3 modifications of small intestine
Plicae circulares
Villi
Microvilli
increase SA x 10
VILLI
VILLIS ARE FINGER LIKE PROJECTIONS OF
MUCOASE
ALL THEE COMPONENTS
IN MAKING VILLI-SURFACE EPITHELIUM HAS INDENTATIONS CALLED
INTESTINAL CRYPTS
CRYPTS OF LEPRACHAUN
pathophys of Celiac disease
gluten sensitivity trigger immune system to damage or destroy villi
-no villi in small intestine
no villi in Small intestine
celiac disease
-gluten intolerant
inc. SA x 100
microvilli
forms striated brush border
microvilli
how do mirovillia function
contain actin-causes them to contract their terminal web-spreads them increasing surface area
where are lacteal
in LP of villi in small intestine
Small intestines have simple columnar epithelium composed of 6 cell types
- enterocytes
- goblet cells
- Paneth Cells
- M cells
- Enteroendocrine
- intermediate cells
primary absorptive cell of the SI
enterocytes
secrete H20 and electrolytes
enterocytes
tall cells with well devloped brush borders
enterocytes
apical portion contains mucinogen granules
goblet cells
FOUND IN BASE OF CRYPTS
PANETH CELLS
FUNCTION OF PANETH CELLS
SECRETE LYCSOZYMES-DIGESTS BACTERIAL CELL WALLS
-CAN ALSO KILL PROTOZOA
REGULATE BACTERIA MICROFLORA IN INTESTINAL GLANSS
PANETH CELLS
APC’s overlying lymphatic nodules
M cells
*eat cells and discharge them into underlying lymph tissue
M cells ar unique in that
microfolds and not microvili
stem cells in small intestinal glands
intermediate cells
*can become any type
paneth cell life
4 weeks
time frame for absoprtive and globet cells
4-6 days
GALT is found in what layer
Lamina Propria
* so closer to lumen than the muscularis mucosa
Peyer’s patches are characteristic of
Illeum
muscularis mucosa in villi
fibers extend into villi and enable movement of villi
Brunner’s glands in
duodenum
glands specific to duodenum in submucosa
brunner’s glands
Function fo Brunner’s glands
secrete alkaline to buffer acid from stomach entering duodenum
peyer’s patches
illeum
bruner’s glands
duodenum
neither Bruner’s or peyers
jejunum
*will have plicae ciruclares
function of large intestines
- absorb water and electrolytes
- elimination of solid wastes and undigested food
longitudinal layer of muscularis external in the large itestines
teniae coli
-three bands
how to now you are in large intestines on histo
WELL DEVELOPED GALT -no plicae circulares -some infoldings no villi/microvilli many straight tubular glands
epithelum of large intestines
simple columnar
-same cell types as SI-more goblet cells and LACKS PANETH CELLS
are paneth cells present in LARGE intestine
HELL NAW
lymph vesssels in LI
non-therefore SLOW METS OF COLON CANCER TO THE LARGE INTESTINES
APPENDIX HAS–
- NO TENIA COLI
- MANY LYMPH NODULES
- USUALLY SHIT IN LUMEN
surface mucous cell also know as
foveolar cells
parietal cells are also called
oxyntic-acid secreting-also make inctrinsic factor for Vitamin B12
abundant granular pink cytoplasm and secrete acid
oxcytnic/parietal cells
found at the isthmus-and have basal nuclei and abundant mucin in cytoplasmic vacuoles above the nuclei
foveolar/surface mucous cells
fundal mucosa normally has what cell types
BOTH oxyntic (pareital) AND chief cells
antral mucosa will have what cell type
normally ONLY cheif cells
cheif cells make
pepsinogen
granular amphophillic bluish cytoplasm in the base of the gland
zymogenic (chief cells)