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
What is the right flexure of the colon called?
The right colic (hepatic) flexure
What is the right flexure of the colon called?
The right colic (splenic) flexure
Names of the parts of the colon
Cecum
Ascending colon
Transverse colon
Descending colon
Sigmoid colon
Rectum
What holds the sigmoid colon?
Sigmoid mesocolon
What holds the transverse colon?
Transverse mesocolon
Where are the epiploc typically absent?
Cecum
Veriform appendix
Rectum
What are the folds of the large intestine called?
Semilunar folds
What is the junction of the ileum and colon called?
The ileal papilla/ ileocolic labrum
What are the 2 parts of the ileal papilla?
Superior (ileocolic) lip
Inferior (ileocecal) lip
What are the semilunar folds of the colon a projection of?
The submucosa
Can the appendix change position?
Yes it is mobile
Different name for enterocytes
Columnar (absorptive) cells
Where are water and salts absorbed?
In the colon
Are there villi in the colon?
No
What are the tubular structures in the colon called?
Intestinal glands (crypts)
Are there microvilli in the colon?
Yes but they are shorter and there are fewer than in the small intestine
What are the intestinal glands mainly made up of?
Goblet cells
What forms the appendices apiploicae?
Small amounts of fat
Where does the rectum start?
At the the 3rd sacral vertebra
Name of the 2 flexures of the rectum
Sacral felxure
Perineal flexure
How long is the rectum in an adult?
About 15 cm
What is the anterior wall of the rectum in contact with in the male?
Urinary bladder
Prostate
Seminal gland
What is the anterior wall of the rectum in contact with in the female?
Uterus
Vagina
Name of the pouch between the anterior wall of rectum and the uterus
Rectouterine pouch/Pouch of douglas
Name of the pouch between the anterior wall of rectum and the bladder
Rectovesical pouch
Which way does the oesophagus curve?
Anteriorly
To the left when it goes through the diaphragm
Where is the cervical part of the oesophagus located?
Between C6-T2
2 parts of the thoracic part of the oesophagus
Mediastinal
Diaphragmatic
Or
Epibronchial
Hypobronchial
Name of the junction between the stomach and the oesophagus
Gastroesophageal junction
What kind of muscle is the stomach?
Hollow and unpaired viscera
Different name for gastroesophageal junction
Z line
Which margin of the stomach is longer, the right margin or the left margin?
The left margin
Which orifice connects the stomach and the oesophagus?
The superior/ cardinal orifice
Which orifice connects the stomach and the duodenum ?
The inferior/ pyloric orifice
Different name for fundus of the stomach
Greater tuberosity
What part of the stomach touches the dome of the diaphragm?
The fundus
Which 4 ligaments attach to the stomach?
Gastrophrenic ligament
Gastroplenic ligament
Gatrocolic ligament
Hepatogastric ligament
What marks the internal surface of the body?
Gastric folds
What determines the gastric folds?
The lifting of mucosa and submucosa
Which axis are the gastric folds directed?
Longitudinal
Are the gastric folds permanent?
No and they disappear when the stomach dilates
What is the sphincter between the duodenum and the stomach called?
The pyloric sphincter
3 layers of the mucosa of the stomach
Surface epithelium
Lamina propria
Muscular mucosae
3 groups of gastric glands in the stomach
Cardial
Principal
Pyloric
Where are the gastric glands of the stomach always located?
The lamina propria
5 cell types of the wall of the gastric glands
Chief
Parietal
Mucous neck
Stem (white)
Neuroendocrine
Which cells are the source of pepsin and lipase?
Chief cells
Which cells are the source of gastric acid (hydrochloric acid) and intrinsic factor?
Parietal cells
Embryological origins of the spleen
Immune cells
Does not originate from the primitive GI tube
Where in the glands in the stomach are stem cells situated?
The isthmus of the gland
Which cells are the source of pepsin and lipase?
Chief cells
Which cells are the source of gastric (hydrochloric) acid and intrinsic factor?
Parietal cells
What is intrinsic factor?
Glycoprotein necessary for the absorption of vitamin B12
Different name for parietal cells
Delomorphic cell
Oxyntic cell
What does the submucosa of the stomach consist of?
Loose connective tissue with elastic fibers and adipose cells
Where is the muscular external of the stomach located?
Immediately under the serosa
Where is the circular muscle layer of the stomach poorly developed?
Oesophageal region
Where is the circular muscle layer of the stomach thickened?
Distal pyloric antrum
Where is the longitudinal muscle layer of the stomach most pronounced?
Upper 2/3 of the stomach
Where is the oblique muscle layer of the stomach most obvious?
In the lower half
What produces the churning movement that mixes food with the gastric secretion?
The actions of muscular externa
Which muscle layer of the GI tract is inner, circular or longitudinal?
Circular layer
Where is the oblique layer of muscle located in the stomach?
Internally to the inner circular layer
What part of the stomach is not covered with the oblique layer?
Lesser curvature
Pyloric part
What is the serosa of the stomach an extension of?
The visceral peritoneum
What part of the stomach does the serosa cover?
Everything but the attachements of the lesser and greater omens to the lesser and greater curvatures
pH of the stomach
2
What signifies the change from the different parts of the small bowel?
No clear distinction but a gradual change in morphology
What its the intersection of the left colic artery with the inferior mesenteric vein called?
Vascular arch of Treitz
Where does the suspensory muscle of the duodenum attach? (hint: it is also called ligament of Treitz)
At the vascular arch of Treitz
Which is the least mobile part of the small intestine?
The duodenum
Is the whole duodenum lined by peritoneum?
No only some parts
Is the duodenal flexure mobile?
No it is pretty much completely immobile
Which part of the duodenum is most mobile?
The superior part
What determines the longitudinal fold of the duodenum?
The common bile duct
Different name for the jejunum and ileum?
Mesenteric small intestine
Which is longer, the jejunum or ileum?
Ileum
In which part of the mesenteric small intestine are lymphoid cells more abundant?
Ileum
What is the mesentery?
A fold of the peritoneum that connects the jejunum and ileum with the posterior abdominal wall
What primarily determines the thickness of the mesentery?
Amount of adipose tissue
4 layers of the small intestine (hint it is the same as the rest of the oesophagogastricointestinal canal)
Mucosa
Submucosa
Muscular layer
Serosa
2 major functions of the mucosa in the small intestine
Digestion and absorption
How much does the circular folds increase the absorption area?
3 times
How much does the villi increase the absorption area?
10 times
How much does the microvilli increase the absorption area?
20-40 times
Which can be considered the most important organ in the digestive organ and why?
The small intestine
Because breakdown of food and absorption takes place
Where is the caecum located?
Right iliac fossa
Different name for sigmoid colon
Pelvic colon
Name of the 3 teniae of the colon
Mesocolic
Omental
Tenia coli
What is the omental appendices?
Peritoneal flaps filled with adipose tissue
Different name for omental appendices?
Epiploic appendices
What separates the cecum and the ascending colon?
Anterior and posterior grooves externally
Internally by the passing through the ideal orifice
Which teniae is located anterior?
Tenia coli
Which teniae is located posterior?
Mental
Which teniae is located medial?
Mesocolic
Where does the variform appendix originate?
Medial wall of the cecum
Where does the colon lack serous lining?
In its posterior surfaces
What leaves the colic impression on the liver?
The right colic flexure
Where does the hepacolic ligeament extend?
From the right colic flexure to the inferior surface of the liver
Where does the Cholecystocolic ligament extend?
Inferior surface of the gallbladder to the right extremity of the transverse colon
Where does the right phrenicocolic ligament extend?
Right colic flexure to diaphragm
Which way does the transverse colon concave?
Upward
How much of the transerve colon is covered in peritoneum?
All of it
How many spaces does the transverse mesocolom divide the peritoneal cavity into?
2
Name of the 2 compartments of the peritoneal cavity
Supramesocolic space
Submesocolic space
Which of the 2 compartments of the peritoneal cavity is smaller?
The Supramesocolic space
2 parts of the sigmoid colon
Iliac tract
Pelvic tract
What is the sigmoid mesocolon?
A double layer peritoneal layer that surrounds the sigmoid colon and connects it to the posterior abdominal wall
What kind of concavity does the sacral flexure of the rectum present?
Anterior
What are the transverse folds of the rectum similar to?
The semilunar folds of the colon
Does the rectum have haustra?
No
What is the anal columns?
5-10 longitudinal elevations located above the anus
Why is the wall of the vermiform appendix thickened?
Due to the precedes of the a considerable amount og lymphoid tissue
2 main types of cells in the superficial epithelium of the mucosa of the colon
Goblet cells
Absorptive cells
Are there lymphoid elements in the colon?
Yes they are very abundant
What is found in the parts of the colon that lack serosa?
Adventitia
What part of the colon is responsible for absorption of nutrients?
The first third up to the middle of the transverse colon
What part of the colon is responsible for water absorption?
The second third from the middle of the transverse colon to the middle of the sigmoid colon
What function does the last third of the colon have (from the middle of the sigmoid colon to the anus)
Reservoir for feces
Name of the 4 constrictions of the oesophagus
Cricoid
Aortic
Bronchial
Diaphragmatic