Digestive Histology Flashcards
GI tract layers (deep to superficial)
mucosa
submucosa
tunica muscularis
tunica serosa/adventitia
three layers/parts of mucosa
surface epithelium
lamina propria
muscularis mucosae
three parts of submucosa
dense irregular fibroelastic CT
blood and lymph
Meissner’s plexuses
what are Meissner’s plexuses for?
motility and secretion of glands
what does the tunica muscularis do?
moves contents of the lumen
inner layer of tunica muscularis is _______ smooth muscle
outer layer is ______ smooth muscle
circular
longitudinal
where are Auerbach’s plexuses and what do they do?
in tunica muscularis, between layers of muscularis externa
regulate activity of muscularis externa
tunica that is connected to body wall is called ______
tunica that is connected to visceral peritoneum is called _______
adventitia
serosa
in esophagus tunica muscularis:
cranial 1/3 is ____
middle 1/3 is ____
distal 1/3 is ____
skeletal
skeletal and smooth
smooth
(voluntary to involuntary control)
environment of stomach is regulated by hormome ____
ghrelin (creates sensation of hunger)
bolus of food is mixed with gastric juices and churned in to
chyme
relaxes smooth muscle lining of stomach to receive a bolus of food
ghrelin
longitudinal folds in the mucosa of the stomach that permit expansion
rugae
4 anatomical areas of stomach
cardia
fundus
body
pylorus
rugae are shallow in _____ and deepest in ______
cardia
pyloric region
rugae with epithelia lining form
gastric pits to increase surface area
at bottom of gastric pits are ________ with these special cells (6)
gastric glands
surface-lining cells - protect from autodigestion
regenerative cells - replace all specialized cells in 5-7 days
mucous neck cells - lubricate lining of stomach
parietal cells - secrete HCL and gastric inhibiting factor
chief cells - pepsinogen and leptin
diffuse neuroendocrine system cells (DNES) - secrete hormones
mucosa of stomach contains (3)
simple columnar epithelium - surface-lining cells
gastric glands opening into bottom of gastric pits
lamina propria - loose fibrous tissue surrounding gastric glands
3 layers of smooth muscle in tunica muscularis of stomach
inner oblique, middle circular, and outer longitudinal
gastric juices are composes of:
water HCL and gastric intrinsic factor enzymes (pepsinogen) glycoprotein soluble mucus
when is pyloric sphincter CLOSED?
only when peristalsis of stomach is happening
pyloric sphincter and stomach movement is regulated by
Gastrin
3 modifications to increase surface area in small intestine
plicae circulares (mucosal/submucosal folds)
villi
microvilli (brush border)
Crypts of Lieberkuhn are found where
mucosa of SI
Brunner’s glands are found where
submucosa of duodenum
cells found in epithelium of small intestine mucosa (3)
surface absorptive cells
goblet cells
DNES cells - produce hormones
most numerous cells of the small intestine; apical surface makes brush border
surface absorptive cells
what is the brush border
3000 microvilli to protect against autodigestion
villi are only found where?
in small intestine
finger/leaf-shaped projections of lumen in to small intestine
villi
enterocytes originate in ______ from _____ and migrate along basement membrane to villus tip to become ______
crypts from germinative cells
absorptive cells
simple tubular glands in small intestine that are continuous with villi and a major source of fluid secretion in teh gut
Crypts of Lieberkuhn
cells that line crypts of lieberkuhn (5)
surface absorptive cells
goblet cells
regenerative cells
paneth cells (manufacture lysozyme)
DNES cells
the connective tissue core of villi in the small intestine
lamina propria
middle of villi is a lymphatic channel called a
lacteal
serous glands that pierce the base of crypts of lieberkuhn in duodenum
Brunner’s glands
what do Brunner’s glands secrete?
basic fluid to neutralize gastric acid and epidermal growth factor to maintain enterocyte growth/health
shortest segment of SI
largest and most numerous villi
fewest goblet cells
duodenum
longest segment of SI
jejunum
segment of SI with fewest and shortest villi and the most goblet cells. Also contains Peyer’s patches
ileum
in small intestine, mixing contractions and propulsive contractions together can cause a
peristaltic rush (rush of chyme into colon)
how much fluid is absorbed by SI each day?
6-7 liters
what does the colon and cecum do?
absorbs most of the water and compacts chyme into feces
colon has lots of _____ in epithelium
goblet cells
crypts of lieberkuhn in LI do not contain
paneth cells
at anal canal tissue transitions from ____ to _____
simple columnar epithelium
stratified squamous epithelium
disease in which “cobblestoning” happens when ulcers separate the mucosa and give it a cobblestone appearance
Crohn’s disease
