Feb13 M1-Histo 1 Flashcards
4 histo layers in GI tract
- mucosa
- submucosa
- tunica muscularis
- adventitia (esophagus) or serosa (visceral peritoneum)
3 layers of mucosa
- nonker squamous stratified epith
- BM
- lamina propria
- muscularis mucosa
cells shapes in squamous stratif epith
bottom: columnar
middle: polygonal
top: squamous
LP contents (in esophagus)
loose CT (lot of cells), mucous glands in upper and lower third of esophagus called cardiac esophageal glands
muscularis mucosa def
SM cells running along GI tube axis.
submucosa contents in esophagus
loose and dense CT mixture + esophageal glands proper: mucous glands giving mucous coat to esophagus for lubricatio. gland opens with duct at lumen
tunica muscularis 2 layers in esophagus
- inner circular running along circumference
- external longitudinal running along GI tube axis
adventitia in esophagus def + fct
dense irregular CT. connects esophagus to other organs of the mediastinum
2 nerve plexuses and location in the GI tube
Meissner’s plexus: in submucosa
Auerbach’s plexus: between inner circular and external longitudinal
Meissner’s plexus fct
(submucosa) PSS innervation to secretory glands
Auerbach’s plexus fct
(between inner circular and outer long) SS and PSS fibers to SM cells
Auerbach’s plexus contents
ganglion cells and unmyelinated nerves
Meissner’s plexus contents
ganglion cells and nerves
missing histo layer in upper esophagus
muscularis mucosa of the mucosa (present only below upper esophagus)
glands along the esophagus
upper: cardiac esophageal glands (LP)
middle: esophageal glands proper (submucosa) (prof says mixed with cardiac esophageal glands)
lower: cardiac esophageal glands (LP)
tunica muscularis content in esophagus
upper: skeletal muscle continuous with pharynx
middle: combination of SKM and SM
lower: SM (inner circular and outer longit)
name of the line between stomach and esophagus and clinical importance
gastroesophageal junction or Z-line
GERD: heartburn
what forms the LES (internal and external)
internal: thickening of the inner circular of the tunica muscularis (esophagus)
external: diaphragm
3 fcts of stomach
- HCl (ph 2)
- IF for B12 abso
- gastrin and sts
characteristic of gastric mucosa
rugae (folds of the mucosa)
2 portions of the gastric mucosa
folds (rugae) and pits (slits between the rugae. are opening of glands)
cells and epith charact in the gastric mucosa
SIMPLE columnar epithelium: surface mucous cells (rugae and pits. pits = openings of glands) and secretory mucous cells (for glands extending within the LP)
charact of the muscularis mucosa in the stomach
instead of 1 longitudinal layer, has inner circular and outer longitudinal
charact of submucosa in stomach
Meissner’s plexus (PSS for glands)
charact of tunica muscularis in stomach
inner oblique
middle circular
outer longit
(Auerbach’s plexus between middle and outer)
serosa in stomach
visceral perit made of CT + layer of mesothelial cells (epith like but derived from mesothelium)
cardia vs pylorus
cardia: pit to gland length is 1:1
pylorus: pit to gland length is 2:1
cardia and pylorus: different mucous cells
surface mucous cells (surface and pit)
secretory mucous cells (glands)
fundus and body pit to gland length ratio
1:3 (glands very long)
cardia is 1:1 and pylorus is 2:1 (pit longer)
diff between glands in cardia/pylorus and fundus/body
fundus and body glands can’t branch and are straight
ONLY thing mucosa of fundus/body has in common with mucosa in cardia/pylorus
both have pits that have surface mucous cells
layer between pit and gland in fundus and body + fct
isthmus. has stem cells (mitosis). make all the cells in the epithelium
other cell type in isthmus + why are diagnostic
parietal cells. also in the gland but not in pit. so parietal cell = isthmus and gland
2 portions of the glands in body and fundus + their cell types
neck: mucous neck cells
base: parietal cells (oxyntic cells), zymogenic (chief) cells, endocrine cells
mucous neck cell charact
columnar, pale, granular, foamy cytoplasm, produce mucin
zymogenic (chief) cells charact
very basophilic
parietal (oxyntic) cells charact
big, acidophilic, canaliculi
surface mucous cells charact (EM)
- microvilli
- lot of mts
- granules on apical side with neutral mucin + bicarb
mucous neck cells charact (EM)
- narrower apical side. wide base.
- acidic mucin that protects gland neck from enzymes of the base
isthmus stem cells: how to diff from mucous neck cells
stem cells = no granules
mucous neck cells = granules
zymogenic (chief) cells charact (EM)
- granules that secrete zymogens (proenzymes) and enzymes: pepsinogen, lipases, rennin
- tight junctions for enzymes not to go between cells
rennin of zymogenic (chief) cells fct
enzyme that coagulates milk. important for digestion of milk in babies by pepsin and lipases
enteroendocrine cells (argentaffin cells) charact (EM)
wider base. base is where stuff is secreted (inversed polarity): secretes granules towards LP
hormones from enteroendocrine cells + 2 important
*gastrin (stim HCl from parital cells)
*Sts (inhibits HCl by parietal cells)
histamine
VIP
glucagon
serotonin
parietal (oxyntic) cells charact (EM)
isthmus to base. large cytoplasm. 2 canaliculi. lot of microvilli, lot of mts
parietal cells chemical processes happening
- takes Cl- from base and puts it out in lumen (Cl-bicarb exchanger)
- makes H+ from CA and puts it in lumen in exchange for K+ (bicarb made from CA taken out by Cl-bicarb exchanger)
what drives the energy necessary for parietal cell secretions + summary of transporters
NaK ATPase on basal surface
base: NaK ATPase + Cl-bicarb exchanger
surface: H-K exchanger
parietal cells other important secretion + clinical significance
make intrinsic factor for B12 abso. autoimmune disease where parietal cells destroyed = atrophic gastritis and pernicious anemia
how to see surface (pit) cells on histo
(surface mucous cells) simple columnar, tall and nuclei at base
how to see parietal cells on histo (isthmus and gland)
acidophilic cytoplasm, centeal nucleus
stomach submucosa
dense irregular CT, Meissner’s plexus
name of tumors of enteroendocrine cells
carcinoid tumors
