8.1 Organs of the Digestive System Flashcards
Is the abdominal cavity distinct from the pelvis cavity?
No. Hence: abdominopelvic
Are the majority of organs intraperitoneal or extraperitoneal?
Intraperitoneal
What vertebrae does the transtubercular plane pass through?
L5
What vertebrae does the subcostal plane pass through?
L3
How do you find the transpyloric plane? What vertebra does it align with?
- Halfway between suprasternal notch and pubic symphysis
- L1
OR: Hands breadth below xiphisternum
What obvious part of the stomach does the transpyloric plane pass through? What is it continuous with?
- Pylorus of stomach (D1).
- Continuous with duodenum
Other than the pylorus, what other part of the stomach sits on the transpyloric plane?
DJ Flexure
What are the four main layers of the GI tube?
- Mucosa
- Submucosa
- Muscularis Propria
- Adventitia
What is the main artery that supplies the foregut?
Coeliac artery
What is the main artery that supplies the midgut?
Superior mesenteric artery
What is the main artery that supplies the hindgut?
Inferior mesenteric artery
What are the boundaries of the foregut?
Mouth to first half of duodenum
What are the boundaries of the midgut?
Second half of duodenum to first two thirds of transverse colon
What are the boundaries of the hindgut?
Last third of transverse colon to anus
Roughly how long is the oesophagus?
25cm
What type of epithelium makes up the oesophagus at different points?
- Mostly squamous
- Distally: columnar
What sphincter separates the stomach and the oseophagus?
LOS (Lower oesophageal sphincter)
What are the three holes in the subcostal diaphragm?
- Inferior vena cava
- Abdominal aorta
- Oesophagus
At what part of the stomach does the gastrooesophageal junction occur? Why is it called this?
- Cardia of stomach
- Named as such because of its close proximity to the heart (after all, it occurs right below the diaphragm)
What is the anatomical/histologically importance of the GOJ?
Anatomical: Prevents oesophageal reflux
Histological: Squamous -> Columnar
What is the name of the condition when the oesophagus is damaged by acid?
Barrett’s oesophagitis
What are the five regions of the stomach?
- Cardia
- Fundus
- Body
- Pyloric Antrum
- Pyloric Canal
Name the two curvatures of the stomach?
Lesser (short way)
Greater (long way)
What are the folds in the mucosa of the stomach called?
Rugae
What is the pH of the stomach?
1.5-3.5
How much stomach acid does the stomach secrete per day? What is in it?
- 1.5L/day
- Contains enzymes (for some absorption) and hydrochloric acid
What are three things that can be absorbed in the stomach?
- Water
- Alcohol
- Aspirin
Which artery supplies the stomach?
Coeliac artery (foregut)
What are the three branches of the coeliac trunk?
- Left gastric artery
- Splenic Artery
- Common hepatic artery
Which artery provides blood to the lesser curve of the stomach?
R/L Gastric Artery
Which artery provides blood to the greater curve of the stomach?
R/L Gastro-omental Artery
Where does the gastro-duodenal artery originate?
Common hepatic artery
What are the greater and lesser omentum made of? Where are they located?
- Made of adipose tissue and peritoneum
- Connected to corresponding curves of the stomach
What is the name of the portal to the liver that the lesser omentum connects to?
Porta hepatis
Name three structures anterior to the stomach
- Abdominal wall
- Diaphragm
- Left liver lobe
Name three structures posterior to the stomach
- Spleen
- Pancreas
- Left kidney
Which two structures drain into the duodenum? At what point do they secrete substances into the duodenum?
- Pancreas
- Gall bladder
Secrete into duodenum at ampulla of vater
How does bile travel to the duodenum?
Common bile duct
How does pancreatic juice travel to the duodenum?
Pancreatic duct
Where are the parts of the duodenum in relation to the peritoneum?
First and fourth: Within
Second and Third: retroperitoneal
List the four sections of the duodenum, and the sections of the GI tract immediately before and after these
- Pylorus
- Superior (L1)
- Descending
- Inferior (L3)
- Ascending
- DuodenoJejunal (DJ) junction
Does the small intestine contain villi or cilia?
Villi
What is the duodenum connected to? What is this connected to?
Duodenum -> Jejunum -> Ileum
What is absorbed in the duodenum?
Iron (among other vitamins and minerals)
What is absorbed in the proximal small intestine?
Nutrients/minerals (e.g. glucose)
What is absorbed in the distal small intestine?
Vitamin B12 and bile acids
How much water is absorbed throughout the small intestine per day?
about 6L
What is the nervous system in the gut?
Enteric nervous system
How does the mucosa change from the jejunum to the proximal isleum to the distal ileum?
Gets flatter; less folds (digestion approaches completion)
What is the mesentery?
Fold of membrane that attaches the intestine to the abdominal wall and holds it in place
Where does blood supply for the jejunum and ileum originate? What are the branches, and what do they form?
- Originate in SMA
- Jejunal/ileal
- Form arcades/vasa recta
Describe the differences in vasculature between ileum and jejunum
Jejunum: Vasa recta long, arcades few large
Ileum: Vasa recta short, arcades many small
Describe venous drainage of the small intestine
- Ileal and jejunal veins
- Drain into SMV
- Join with splenic vein to form portal vein -> drop off nutrients in liver on way to heart
