gastrointestinal tract Flashcards
what are the three sections of the mucosa ?
epithelium: absorption of nutreints
lamina propria: gastric glands in the stomach
muscularis mucosa: motility
in which layer is the nervous plexus found in ?
submucosa
meisseners plexus
what does a lack of meisseners plexus result in ?
hurschprungs disease
what is the pathology associated with hirschprungs disease?
happens due to the absence of ganglion cells in the submucosal layer due to the failure of neural crest migaration
what is the other plexus in the muscular layer ?
auerbachs plexus
abnormal in achalasia
what is the epithelium of the esophagus ?
startified squamous epithelium
what is the epithelial layer of the stomach and what are the histological hallmarks of the stomach ?
simple columnar epithelium
gastric pits
gastric glands
what is unique about the structure of the small intestines ?
villi
which layer is present in the villi in the small intestines ?
mucosa
which layer is present with microvilli in the small intestines ?
epithelial cell membrane
what are the pilcae circulares ?
valves of kerckring
folds of mucosa and submucosa
most abundant in the jejunum
increase surface area for absorption
what do goblet cells form ?
mucous
where are goblet cells normally found and when are they not supposed to be found ?
usually found in the small and large intestines
not supposed to be found in the gastric mucosa - sign of intestinal metaplasia
what are brunner glands ?
only in the duodenum
found in submucosa and they produce alkaline to neutralize acid
what is the clinical correlation of brunners gland ?
increase in thickness in peptic ulcer disease
what are peyers patches ?
analogous to lymph nodes found in the mucosa
where do we find brunners glands vs peyers patches ?
brunners gland - duodenum
peyers patches - ileum
if you find neither than we are in the jejunum
what are lacteal and what are their function ?
lymphatic channels within villi in the small intestines
important for fat absorption
what is the hallmark of mucosa of the colon ?
crypts with no villi
what is the difference between the term erosion vs ulcer ?
erosion is just the mucosa
ulcers : submucosa and muscularis mucosa
what are the two enteric nervous systems ?
submucosal plexus ( meissener’s )
myenteric nerve plexus ( auerbach)
what are the roles of the different enteric nervous systems ?
1- Meisseners is more responsible for secretions and blood flow
2- Auerbach is more responsible for Gi motility
what are the slow waves of the GIT ?
1- oscillating membrane potential that happens in the smooth muscles
2- the impulse starts from interstitial cells of cajal
sets maximum number of contractions per time
what are the pharyensgeal arches associated with the development of the tongue ?
1st pharyngeal arch - anterior 2/3 of the tongue
3rd and 4th pharyngeal arches form the posterior 1/3 of the tongue
what cranial nerves are associated with taste in the tongue ?
CN
7
9
10
what is the motor innervation of the tongue ?
CN 7
through genioglossus
styloglossus
CN 10
to palatologlossus
what week of development does physiologic herniation happen ?
week 6 , done by week 10
what week does the physiologic rotation of the gut happen ?
week 4-6
what is the defect associated with congenital umbilical hernia ?
delay of umbilical ring to close spontaneously following physiologic hernation of the midgut
what type of esophageal atresia is associated with a gassless abdomen ?
H type
how does cyanosis in TE anomalies happen ?
secondary to laryngospasm
what type of metabolic dysfunction is associated with pyloric stenosis ?
metabolic alkalosis
what are the radiological signs associated with jejunal and ileal atresia ?
triple bubble sign and gasless colon
what conditions may be associated with a higher incidence of jejunal and duodenal atresia ?
cysti fibrosis
gastroschisis
maternal tobacco use
use of vasoconstrictions during pregnancy
what is nutcracker syndrome ?
compression of the left renal vein between SMA and aorta and may cause abdominal pain , gross heamturia and left sided varicocele
