GI tract Flashcards
Where does the oesophagus start?
C6
What is the oesophagus mainly made by?
Muscle
What does the oesophagus connect?
The pharynx to the stomach
Where is the oesophagus located in relation to the trachea?
Posterior
Where is the oesophagus located in relation to the heart?
Posterior
Where does the oesophagus go through the diaphragm compared to the aorta?
Anterior
Name of the 3 parts of the oesophagus
Cervical
Thoracic
Abdominal
Which is the longest part of the oesophagus?
Thoracic part
Which is the shortest part of the oesophagus?
The abdominal part
How many constrictions of the oesophagus?
4
What is the middle (thoracic) constriction because of?
The aorta
What is the upper (pharyngoesophageal) constriction of the oesophagus because of?
The pharynx
What is the lower (phrenic) constriction of the oesophagus because of?
The diaphragm
What part of the mediasternum is oesophagus located?
Posterior
What kind of organ is the oesophagus?
Empty organ
Layers of the oesophagus wall (inner to outermost)
Mucosa
Submucosa
Muscular externa
Adventitia (in cervical and thoracic part)/serosa(in abdomen)
What kind of epithelium is found in the wall of the oesophagus?
Stratified squamous, non keratinising epithelium in the lumen
What kind of muscle in the upper third of the muscolaris external of the oesophagus?
Skeletal
What kind of muscle in the middle third of the muscolaris external of the oesophagus?
Mix of both skeletal and smooth
What kind of muscle in the bottom third of the muscolaris external of the oesophagus?
Smooth
What is the passage from oesophagus to stomach called?
Cardias
Where can the oesophageal diverticula happen?
At the spots of weakness
What arteries supplies the cervical part of the oesophagus?
Oesophageal branch of inferior thyroid artery
What arteries supplies the thoracic part of the oesophagus?
Oesophageal branch of descending thoracic aorta
What arteries supplies the abdominal part of the oesophagus?
Oesophageal branch of left gastric artery
Which veins supply the abdominal part of the oesophagus?
Oesophageal branches of left gastric vein
Which veins supply the thoracic part of the oesophagus?
accessory hemiazygos vein (SVC system)
Which veins supply the cervical part of the oesophagus?
Inferior thyroid vein (SVC system)
What kind of nerves innervate the oesophagus?
Sympathetic and parasympathetic
3 parts of the small intestine
Duodenum
Jejunum
Ileum
Rough length of the small intestine in an adult
5 meters
Where does the duodenum mostly lie?
Mostly in the upper retroperitoneum
Where does the jejunum and ileum lie?
Intraperitoneal
What does the small bowel consist of?
Jejunum and ileum
Do the superior mesenteric vessels have a relationship with the duodenum?
Yes anterior at the 3rd part
What goes in the epatoduodenal ligament?
Bile duct
Hepatic artery & portal vein
Where are the IVC and aorta located in relation to the 3rd part of the duodenum?
Posterior
What is the duodenomesocolic fold a result of?
The behavior of the duodenum and its move from retroperiotneal to intraperiotoneal
What landmark pinpoints the passage from the duodenum to the jejunal?
The Duodenojejunal flexure
How does the inner surface of the first part of the duodenum differ from the rest?
It is smooth, no circular folds
Different name for the 1st part of the duodenum
Ampulla
Duodenal bulb
What are the folds on the inner surface of the duodenum and small bowl called?
Circular folds
What does the major duodenal papilla receive?
Common pancreatic duct and bile duct
What does the minor duodenal papilla receive?
Accessory pancreatic duct
Where are the duodenal papillae located?
Medial wall of the descending duodenum
Different names for major duodenal papilla
Hepatopancreatic ampulla
Vater
Different name of the sphincter of hepatopancreatic ampulla
Oddo’s sphincter
What joins to form the ampulla which makes up the major duodenal papilla?
Common bile duct and pancreatic duct
Where does the greater omentum originate?
Transverse inferior part of the stomach
What covers the small intestine and transverse colon?
The greater omentum
What is the mesentery formed by?
2 layers of peritoneal
What suspends the small intestine?
The mesentery
What causes the folds in the small intestine?
Projection of the submucosa
What does the submucosa of the duodenum contain?
Submucosal duodenal glands/ Brunner’s gland
What does the submucosa of the ileum (and lesser extent jejunum) contain?
Preyer’s patches
What are the villi due to?
Projection of basal membrane of the mucosa
Function of the projections of the small intestine
Increasing absorbing surface by increasing absorbing surface area
Is there a landmark marking the passage from the jejunum to ileum?
No, its a smooth transition
Where are the circular folds higher and more frequent, ilium or jejunum?
Jujneum
What is the lacteal (in the villi)?
Tiny lymphatic vessel
What do the lacteal absorb?
Chylomicron which are too big to be absorbed in blood capillaries
Where in the villus is the lacteal located?
The central axis
Main cell types of the epithelium covering the intestinal villi and line intestinal glands
Enterocytes
Goblet cells
Name of the intestinal glands
Crypts of the lieberkhun
What kind of epithelium is found in the small intestine?
Single columnar epithelium
What forms the microvilli?
The membrane of the enterocytes
Cell types of the intestinal crypts
Paneth cells
Stem cells
Neuroendocrine cells
Goblet cells
Enterocytes
How hare the enterocytes in relationship with each other?
Through tight junctions (desmosome)
What are transient apmlifying cells?
A cell formed from stem cells which will become mature cells such as enterocytes
What do panted cells produce?
Lysozyme and other defensive proteins (defensins)
What do neuroendocrine cells produce?
Gastrin
cholecystokinin
Secretin
Why are the submucosal Brunner’s glands only located in the duodenum?
Because to receives the acid from the stomach and the Brunner’s glands neutralise the chyme
What neutralises the chyme?
The Brunner’s gland which secrete an alkaline (pH9) mucoid secretion
How long is the large intestine in the adult?
1.5 meters
Name of the pouches of the large intestine
Haustra
Different name for large intestine
Colon
First part of the large intestine
Cecum
Full name of the appendix
Vermiform appendix
Where does the terminal part of the ileum enter the colon?
The medial wall