Digestive system Flashcards
Peyer’s patches
clumps of lymphatic tissue (also called aggregated lymphoid nodules) that are found in the ileum of the small intestine
they have immune function of preventing bacterial overgrowth in the small intestine
GALT is found in which layer of digestive tract?
mucosa’s lamina propria
layers of mucosa
Lining epithelium (mucous membrane) Lamina propria Muscularis externus
Location and function of Meissner’s plexus
In the submucosa
Innervate muscles of mucosa muscularis externus and blood vessels
Where only does submucosa have glands?
Esophagus and duodenum
Auerbach’s plexus
found between circular and longtudinal layers of muscularis externus of mucosa
Characteristic of outer longitudinal layer of mucosa in large intestines
It is d iscontinuous
Extent of oesophagus
from neck to mediastinum of chest (space between the lungs) and abdomen
Unique features of the oesophagus
- It’s one of the only two places whose submucosa has glands. its glands are called proper glands
- In its entire length, lining is stratified squamous non-keratinized
- Its muscularis externa has both smooth and skeletal muscle in addition
Explain distribution of smooth and skeletal muscle along length of oesophagus
Upper 1/3rd only skeletal muscle
Middle 1/3rd, both skeletal and smooth
Lower 1/3rd, only smooth muscle
Type of connective tissue of mucosa’s lamina propria
Loose irregular CT
Connective tissue type of submucosa
Dense irregular CT
Difference between serosa and adventitia
serosa is the covering of esothelium (walls of cavities) and is found where GIT is hanging freely
Adventitia is connective tissue that connects structures
Main function of stomach
dissolve and mix ingested food creating chyme
Function of rugae
folds that allow for expansion of stomach
Gastric pits are found in the ____ of the mucosa
mammillated areas
3 parts of gastric glands
neck
isthmus
fundus
Composition of stomach mucous
bicarbonate
How cloudy mucous protects stomach from its acidic pH
since it’s alkaline, it raises pH at the surface to 4-5 from the pH of 1-2 of gastric juices
Hiatus hernia
when part of the stomach protrudes through a cavity in the diaphragm. more common in women than men and is usually asymptomatic.
can cause reflex of stomach contents into oesophagus
Most common site of stomach cancer
esophago-gastric junction
Tubulovesicular system
a system of membranes
Pyroli sphincter formed by which layer of the stomach
3rd layer /oblique layer
Main function of intestine
absorption of nutrients and other components of food (completes digestion process)
Area of small intestine with greatest surface area for absorption
Jejunum
Compare the plicae circulares of the different parts of the small intestine
*MNEMONIC for parts of small intestine: DJ Izzy
plicae circulares are thicker, taller, and more
numerous in the jejunum than in the duodenum or ileum.
Valves of Kerkring
submucosal extensions that project into intestinal lumen to increase surface area for absoprtion
also called Plica Circularis
True or false: Villi are submucosal projections
False: villi are mucosal projections
Crypts of Lieberkhun
epithelia of the villi extending down into the lamina propria where they form crypts which are glands
their Paneth cells secrete intestinal juices
Type of secretions produced by crypts of lieberkhun
serous
Function of Paneth cells of intestinal crypts
provide innate immunity
Main function of large instestine
Passive absorption of water
Gastroesophagial reflux disease (GERD)
In which inferior sphincter of oesophagus is not working and there is reflux of stomach acid into the oesophagus. Because the mucous of the oesophagus does little to protect against acid, it can lead to metaplasia of the stratified squamous non-keratinized changing to simple columnar cells forming Barret oesophagus
Barret esophagus
complication of GERD (gastroesophageal reflux disease). dangerous because it can lead to cancer (ESOPHAGIAL ADENOCARCINOMA)
Characteristics of protein-secreting cells
Prominent nucleolus
Basophilic cytoplasm
Extensive ER
Gastrin is produced by
G cells (type of enteroendocrine cells)
Crohn disease; location, causes, and symptoms
Disease of digestive tract most commonly affecting ileum or colon.
Caused by combination of genetic and environmental and autoimmune factors.
Symptoms include excess lymphocyte activity in all layers of GIT wall of affected area, bleeding, mal-absoprtion, pain, and diarrhea
Difference between adsorption and absorption
in absorption, the molecule penetrates through the liquid/solid doing the absorbing. but in adsorption, the molecule adheres and concentrates on the surface without going through it
Function of small intestine’s glycocalyx coat
Adsoprtion of nutrients then the enzymes present on it digest those nutrients which are then absorbed
Function of Brunner’s glands. In which part of the GIT are they found, and in which layer?
To secrete mucous
They are found in the duodenum of small instestine in the submucosa
Location of Crypts of Lieberkhun.
The small and large intestie
Location of anal transitional zone. What happens here?
Located in the middle 1/3rd of anal canal
Cells changes from simple columnar to stratified squamous
Enumerate the Zollinger-Ellison Syndrome.
also called Gastrinoma
a tumor of enteroendocrine cells at the gastroduodenal junction that produces excess gastrin hormone = excess HCl production = peptic ulcers
Which type of gland has the most parietal and chief cells?
fundic glands
Differentiate pyrolic glands from cardiac and fundic glands.
Extend up to submucosa of duodenum unike the cardiac and fundic glands which only reach mucosa
