Upper GI Flashcards
What are the five phases of breakdown of food?
ingestion, fragmentation, digestion, absorption, and elimination
What occurs in the oral cavity (in digestion)?
ingestion, accompanied by fragmentation, resulting in bolus formation
What does the stomach do?
completes fragmentation and initiate digestion
What is peristalsis?
contraction of smooth muscle under autonomic control
What causes emulsification of fat?
duodenum, pancreatic, and biliary secretion
Where does absorption of nutrients occur?
jejunum and ileum
Where does absorption of water and elimination of waste occur?
colon
Where does ingestion and begining of fragmentation occur?
oral cavity
Where does fragmentation complete and digestion begins?
stomach
What anchors the tongue to the floor of the mouth?
lingual frenulum
What does too short of a frenulum cause?
ankyloglossia/ tongue tied
What are the characteristics of the gastrointestinal tract?
- muscular tube lined by mucus membrane
- large # of glands
- diffuse lymphoid tissue (MALT, GALT)
What are the four layers of the GI tract?
mucosa, submucosa, muscularis, and serosa (adventitia)
What is the function of the mucosa layer of GI?
protection, secretion, absorption
What are the subdivisions of the mucosa layer of the GI?
epithelium, lamina propria, muscularis mucosae
There are different types of mucosa depending on what?
different functions for different locations
What layer of the GI surrounds the lumen of the GI?
mucosa
What layer of the mucosa is a thin cell layer?
epithelium
What layer of the mucosa is a thin layer of connective tissue?
lamina propria
What layer of the mucosa is a thin layer of smooth muscle that supports the mucosa and provides the ability to move and fold?
muscularis mucosa
What are the four types of mucosal variation?
protective mucosa
secretory mucosa
absorptive mucosa
absorptive/protective mucosa
What are the characteristics of the protective mucosa?
- stratified squamous epithelium
- in oral cavity, pharynx, esophagus, and anal canal
What are the characteristics of the secretory mucosa?
- responsible for the secretion of digestive enzymes
- only in stomach
What are the characteristics of the absorptive mucosa?
-contains crypts and villi
- responsible for absorbing digested nutrients
- in the small intestine
(along the entry of the small intestine)
What are the characteristics of the absorptive/protective mucosa?
- water absorption
- mucous secretion
- in large intestine
Where are the four points in which the mucosa layer of GI undergoes abrupt transition from one type to another?
- gastro-esophageal junction
- gastroduodenal junction,
- ileocecal junction
- anorectal junction
What are the characteristics of the epithelium layer of mucosa GI?
- different modifications are different levels of GI tract
- thin layer of cells
What are the characteristics of the lamina propria layer of mucosa GI?
- underlying connective tissue
- contains lymphoid nodules, glands, blood vessels, and lymphatics
What are the characteristics of the muscularis mucosae layer of the mucosa GI?
- thin layer of smooth muscle
- boundary between mucosa and submucosa layers
What is the submucosa of the GI tract?
thick connective tissue layer that contains arteries, veins, lymphatics, and nerves
What is the muscularis externa of the GI tract?
surrounds the submucosa and is composed of two muscle layers, the inner circular layer and outer longitudinal layer
-move perpendicular to each other
What plexus is located in the submucosa layer of GI?
Meissner’s Plexus
What plexus is located in the muscularis propria (externa) layer of GI?
Auerbach’s (myenteric) plexus
What layer of the GI tract is thick connective tissue layer tha contains arteries, veins, lymph, and nerves?
submucosa
What layer of the GI tract surrounds the submucosa and is composed of two muscle layers (inner circular and outer longitudinal)?
muscularis externa
What do the two muscle layers of the muscularis externa allow for?
layers move perpendicularly to one another and formt he basis of peristalsis
What layer of the GI tract consists of connective tissue with blood vessles, nerves, and fat?
Adventitia/serosa
What is the adventitia/serosa layer of the GI lined by in the peritoneal cavity?
mesothelium
What allows for local contraction (mixing of food in either direction)?
segmentation
What propels food distally only?
peristalsis
What layer of the GI tract is continous with the supporting mesentery?
adventitia/serosa
Smooth muscle of the gut is controlled by ________________
autonomic nervous system
Parasympathetics in the gut are __________
excitatory
Sympathetics in the gut are __________
inhibitory
Where are the parasympathetic ganglia located in the GI tract?
within the walls of the gut (submucosa and muscularis externa)
Clusters of parasympathetic ganglia within submucosa; called _______ ______
Meissner’s plexus
Larger clusters located between inner circular & outer longitudinal Mm layers called __________ _____________
myenteric/Auerbach’s plexus
What two layers is the Auerbach’s plexus between?
between the circular muscle and longitudinal muscle layers of the muscularis externa
key difference between Meissner’s and Auerbach’s plexus:
Meissners is in the submucosal where Auerbachs is between the circular and longitudinal layers
Anatomical position of the esophagus?
travel through the mediastinum and pierce the diaphragm
Where does the esophagus meet the stomach?
cardiac orifice
What type of epithelium is the esophagus lined by?
stratified squamous nonkeratinized epithelium
Where is the site of GERD and the site of most esopageal cancers?
the distal/bottom of the esophagus
What prevents air from entering the esophagus?
resting muscle tone in the circular muscle layer in the superior 3cm of esophagus
What prevents backflow from stomach into the esophagus?
resting muscle tone at the inferior end of esophagus (not an actual sphincter)
What type of muscle is in the thirds of the esophagus?
upper third - skeletal muscle (voluntary)
middle third - skeletal and smooth
lower third - smooth muscle
What is the protrustion of the upper part of the stomach into the thorax through a tear of weakness in diaphragm?
hiatus hernia
or
hiatal hernia
What are the different types of hiatus hernia?
sliding - 90%
rolling - 5%
mixed - 5%
What type of hiatus hernia is rare?
congenital esophageal hernias
What is the sphincter between the esophagus and stomach?
gastroesophgaeal sphincter
What is the junction between the esophagus and stomach called?
gastro-esophageal junction
What is pyrosis?
“heartburn”
- regurgitation of stomach acid into distal esophagus from cardia of stomach
What is Barrett’s esophagus?
- a serious complication of GERD
- acid from stomach changes the esophagus lining (stratified squamous to simple columnar)
- increase the risk of esophageal adenocarcinoma
What are the symptoms of esophageal cancer?
- difficutly and pain when swallowing
- pressure/burning in chest
- indigestion/heartburn
- vomiting
- frequent choking
- unexplained weight loss
- coughing/hoarseness
- pain behind the breastbone
What are risk factors for esophageal cancer?
smoking, poorly controlled acid reflux, gum disease
Esophageal cancer is treatable but rarely curable. The 5 year survival rate ranges from _______ to ________%
5-30%
