GI Flashcards
in an embryo, from what layer does the gut come from?
endoderm
what are the layers of the gut tube?
- mucosa
- submucosa
- muscularis
- serosa
what sublayers does the mucosa have?
epithelium
lamina propria
muscularis mucosa
what components does the submucosa have?
glands
vessels
submucosal plexus
what are the layer of the muscularis?
inner circular
myenteric plexus
outer longitudinal
what is another name for the serosa?
adventitia
identify the layers of the gut.
What are the layers of the tunica mucosa? what do they do?
epithelium mucosa: absorption, secretion, protection
lamina propria: contains vessels & nerves
lamina muscularis: inconstant
what are the surface modifications of the mucosa (or epithelium)?
villi
plicae
crypts
pits
What are rugae?
large folds in stomach
what are pits?
invaginations in the stomach
what are plicae?
large folds in small intestine
what are villi?
projections in the lumen found in small instestine
what are crypts?
invaginations in small and large instestine
what is this?
rugae
what is this?
pits
what is this?
villi
what is this?
crypts
what are these?
big circle = plicae
small proyection = villi
where is the arrow pointing at?
where is this?
crypts of jejunum
where is the arrow pointing at?
where is this?
crypts of ileum
what is the square and the circle?
circle: crypts
square: villi
what is the arrow pointing at?
the tunica submucosa
what does the submucosa do?
it facilitates motility of the submucosa
how do you call the submucosa if there is no lamina muscularis present?
lamina propria/sumbucosa
what layer is the box?
submucosa
the muscularis layer can be two types of muscle, what are these?
smooth and skeletal muscle
what is the layer of the square?
muscularis layer
how many layers does the muscularis layer have?
2 : outer and inner muscular layer
what does the muscular layer do?
controls lumen size
what important structure is found in the muscular layer?
myenteric plexus
what is this?
the two layers of the muscular layer
what are the 3 boxes?
what is this layer?
serosa
where can we find serosa?
in organs that are suspended in body cavities
where is the serosa, adventitia instead?
organs covered in connective tissue
esophagus
rectum
vagina
name the layers
what is a plexus?
Elements of two ANS divisions & enteric NS in same location in wall.
what controls the effectors or glands and smooth muscle of an organ?
parasympathetic and enteric nervous systems
what are the arrows pointing out?
parasympathetic neuron cell bodies of myenteric plexus
how well does the esophagus heal?
not well
how many sphincters does the esophagus have?
2: upper and lower
what is this?
the esophagus
the mucosa of the esophagus contains what kind of epithelium?
what layers does the esophagus have?
non keratinized stratified
it contains:
epithelium
lamina propria
smooth muscle (muscularis mucosa)
what does the submucosa have?
glands that secrete mucous
what muscle is in the muscularis of the esophagus?
upper 1/3 muscularis is skeletal muscle
middle 1/3 is skeletal and smooth
lower 1/3 is smooth muscle
the lamina propria of the esophagus contains what?
esophageal cardiac glands
what is special of the muscularis mucosae of esphagus?
it is a single layer of longitudinally smooth muscle
what is the composition of the submucosa of esophagus?
dense, fibroelastic connective tissue that houses the esophageal glands proper
what is the name of the plexus between the longitudinal muscle layer and inner circular muscle layer?
auerbach plexus
what is this epithelium?
non-keratinized stratified epithelium
what does the lower esophageal sphincter do?
it prevents backflow of food and prevents stomach acids to rise
what part of the esophagus is this?
middle 1/3
where is this?
esophagus
what is happening here in the esophagus?
metaplasia
how many layers does the muscularis of the stomach have?
3 for proper mixing
what cells can be found in the fundus and body?
cells that secrete pepsinogen and HCL
what do the glands of the pylorus and cardia secrete?
mucous
what enzymes are produced in the stomach?
rennin, pepsin, gastric lipase
what are the 3 glandular regions of the stomach?
cardia
fundus
pylorus
this organ has longitudinal folds called…?
rugae; the stomach
identify
Stomach wall at the fundus: mucosa (M), submucosa (SM), muscularis externa (ME), serosa (S).
this layer is connective tissue, with blood vessels and lymphatics?
submucosa of stomach
what is the esophagogastric junction?
it is the junciton of the esophagus with the cardiac region of stomach
the epithelium changes in the esophagogastric junction, from what to what?
from stratified squamous to simple columnar with invaginations (gastric pits)
what separates the mucosa from the submucosa in the stomach?
muscularis mucosae
from where to where do the fundic glands extend to?
from muscularis mucosae to base of the gastric pit
what epithelium do fundic glands have?
simple columnar
what are the 6 cell types for the fundic glands?
- surface lining cells
- parietal (oxyntic) cells
- regenerative (stem) cells
- mucous neck cells
- chief (zymogenic) cells
- diffuse neuroendocrine system (DNES) cells
what is the P?
gastric pit
what is this?
surface mucous cells continous with gastric pits
what do gastric glands do?
produce mucous with higher concentration of glycoproteins
what do parietal cells produce? what organelle do they require?
HCl; mitochondria
they also produce intrinsic factor (b12 absorption)
are parietal cell eosino-basophillic?
eosinophillic
are chief cells eosinophillic or basophillic?
basophillic
what do chief cells secrete?
pepsinogen which is a protease
which are the pyloric glands and which are the gastric glands?
top are gastric
bottom are pyloric
what does the epithelium of fundic glands produce? what do they secrete?
alkaline mucous;
pepsinogen and lipase
what three glands are in the fundic glands?
- chief
- parietal
- entero-endocrine
what are the 3 white cels?
parietal cells
what do entero-endocrine cells secrete?
serotonin
what are these?
chief (basophillic) and parietal (acidophillic) cells in fundic gland
what are these cells and what do the red dots secrete?
chief cells and the red dots are zymogen
what is this?
parietal cell
parietal cell have receptor for what? binding of the molecules to the receptor causes what?
gastrin, histamine and acetylcholine;
binding causes cell to make hcl and store it in canneliculi
What do carbonated anti-acids do? what do prolonged use cause?
neutralize acids, can cause kidney failure
What do H2 blocker anti-acids do? what do prolonged use cause?
they block histamine decreasing parietal cell activity (including intrinsic factor)
What do proton pump inhibitors anti-acids do? what do prolonged use cause?
they block acid production; this can cause dependency long term causes osteoporosis
what is this?
parietal cell
what are these cells?
top parietal
below chief
what is this?
pyloric gland
where are G cells?
they are carried in special capillaries to proper gastric gland region
what do G cells secrete?
gastrin
what does gastrin do?
it increases motility, HCl, and pepsinogen
what is this?
G cell
what is the sympathetic innervation of the stomach?
what is the para sympathetic innervation of the stomach?
splanchnic nerves
vagus nerve
What is pernicious anemia?
occurs due to lack of intrinsic factor thats secreted by parietal cells.
It causes B12 deficiency
what is peptic ulcer disease?
caused by helicobapter pylori, causing excess secretion of acid
what do the 3 parts of the small intestine do?
- duodenum: last part of digestion
- jejunum: absorb product of digestion
- ileum: immunological protection
what does the lamina propria of small intestine have?
glands
cypts of lieberkuhn
blood vessels
what does the crypts of lieberkuhn contain?
DNES
surface absorptive
goblet cells
regenerative cells
paneth cells
where can Brunner glands be found?
duodenum
where are peyer patches found?
ileum
what is the epithelial composition of villi in the small intestine?
simple columnar
it is made up of enterocytes and goblet cells
What are the arrow pointing at?
plicae circulares
the final breakdown of proteins, carbs and lipids occurs where?
in the microvilli
what is an intestinal crypt?
invagination into the lamina propria forming short tubular glands
where are paneth cell located?
at the base of the crypts
what is this?
paneth cell
what is this?
enteroendocrine cell
what is this cell in the middle?
enteroendocrine cell
what is this?
paneth cell
what is this?
paneth cell
what is being shown?
paneth cell
what do secretions of enteroendocrine cells do?
control gut motility, regulate secretion of enzymes, HCl, bile and other components for digesti
is this the ilieum or duodenum?
duodenum
is this the ilieum, jejunum or duodenum?
ileum
is this the ilieum, jejunum or duodenum?
jejunum
is this ileum, jejunum, or duodenum?
duodenum
what is another name for the mucosal cells of the duodenum?
brunner glands
what is characteristic of the duodenal villi?
it has long villi
which are brunner glands?
is this duodenum, ileum or jejunum?
duodenum
is this jejunum, ileum, duodenum?
duodenum
is this duodenum, ileum, jejunum? what are the layers?
duodenum
in order:
mucosa, submucosa, muscularis, serosa
what do jejunum and ileum lack?
submucosal glands
what do ileum and jejunum have increasing amounts of?
goblet cells
what are two characteristic things of the jejunum?
prominent plicae circulares
nonremarkable submucosa
what are 5 characteristics of the ileum?
- Peyer’s Patches
- M cells
- bile acid re-absorption
- absorption of intrinsic factor for B12
what is this?
plicae
how is the white center called?
lacteal
what are the blue parts?
peyer patch
what are the round blue parts?
peyer patches
where are m cell located?
overlying peyer’s patches
what do m cells do?
they endocytose antigens and transport them to lymphocytes and macrophages
what is the function of the large intestine?
- absorb water
- mucus production
what is this?
large intestine crypt
where is this?
appendix
the lamina propria and submucosa of the appendix is filled with what?
lymphocytes
what type of epithelium does the anus and rectum have?
simple columnar
what controls the anus and rectum?
internal/external sphincter
what are hemorrhoids?
dilatation of venous plexus forming varicose vein in the anal/rectal region
what epithelium is in the anus?
transition from simple columnar to stratified squamous
what are 4 symptoms of ulcers in the GI tract?
abdominal pain
nausea and vomiting
hemamtemesis (blood vomiting)
melena (tarry foul smelling feces)
what does diarrhea cause?
dehydration
K+ deficiency
what is diverticulosis?
Outpocketings of the colonic mucosa and submucosa through weaknesses of muscle layers in the colon wall.
diverticulosis is most common in which part of the large intestine?
sigmoid colon; due to increased pressure
what is going on?
diverticulosis
what is diverticulitis?
Tears in the colon leading to bleeding or perforations may occur.
it can lead to intestinal obstruction or abcess
what is a polyp?
Typically hyperplasia of epithelial glands
what is a symptom of polyps?
diarrhea, pain, rectal bleeding
*there is an increased chance of cancer
what is this?
polyp
what is this?
tubular adenoma
what is this?
villous adenoma
where does colon cancer occur?
in the lining of the colon and if untreated can grow into muscle layer.
are cancers that are confined to the wall of the colon, are they curable?
yes (are still in situ)
