Session 1 - Purpose Of The Gut Flashcards
Which areas of the GI mechanically disrupt food?
Mouth/Teeth Muscular stomach (especially lower area - strong peristaltic contractions, due to thicker distal muscle)
Describe the muscular layers of the stomach wall
- Longitudinal outer layer
- Circular middle layer
- Oblique inner layer
Smooth Muscle
What are the main functions of the stomach?
- Distend to STORE food (we eat quicker than we can digest)
- Mechanically disrupt (muscle)
- Chemically break down (H+, enzymes)
Broadly, what defences does the GI have against pathogens?
Saliva (IgG)
HCL
Liver - kupffer cells
Peters patches (ileum)
What is haustral shuttling
slow, uncoordinated movements of chyme from one Haustrum to another in the Colon.
(Haustrum - pouch of colon)
What is a Haustrum?
Small pouches of the colon caused by sac formation, giving the segmented appearance.
Which features of the gut give a large surface area for absorption?
The long length.
Many folds.
Villi and Microvilli
What is the gastrocolic reflex?
One of many physiological reflexes controlling gut motility and peristalsis of the GI tract.
> Motility in response to stomach stretch, and byproducts of digestion in SI.
Name the different sites of the GI tract in order, from mouth to anus.
Mouth Oesophagus Stomach Duodenum Jejunum Ileum Caecum Ascending colon Transverse colon Descending colon Sigmoid colon Rectum Anus
What is the function of the upper and lower oesophageal sphincters?
Upper
Just below oropharynx, prevents air entering GI.
Lower
Helps prevent reflux of stomach contents into oesophagus
Which part of the GI are most of the nutrients absorbed?
Jejunum
Where is most water absorbed in the GI?
Ileum
What is the definition of peritoneal cavity?
Space between the parietal and visceral peritoneum
What is it called where there is a DOUBLE fold of peritoneal cavity (around an organ)
Mesentry
Arteries, veins & lymphatic drainage etc.
What is in the peritoneal cavity?
Nothing but small amount of fluid
What are abdominal structures NOT supported in the peritoneum referred to as?
Retroperitoneal
Lie behind the peritoneum
What is endoscopy?
Visualisation, biopsy taking, or therapeutic treatment of part of the GI tract using an endoscope, containing a camera.
What condition commonly affects the junction between oesophagus and stomach?
Chronic acid exposure - reflux.
Barrett’s oesophagus
Which common condition is visualised in the stomach during endoscopy?
Gastric ulceration.
Often benign, irregular border can signal malignancy
(Biopsy is mandatory)
Which common condition may be found in the duodenum during endoscopy?
Duodenal ulcers common in 1st part.
Why may an anterior duodenal ulcer be more serious?
Thinner unprotected wall, with less mucus protecting it.
Anterior ulcer may perforate causing peritonitis.
What may be a complication of a posterior duodenal ulcer?
Erosion into gastroduodenal artery, which may cause massive haemorrhage and bleeding.
(Or into pancreas - severe pain)
What is ERCP, what could be found?
Endoscopic retrograde CholangioPancreatography.
Common obstruction of the bile duct, causing jaundice (bilirubin cannot be removed)
What may cause obstruction of the bile duct?
-Painless obstruction
Usually secondary to a tumour. (E.g. carcinoma of pancreas, bile duct cancer, etc)
-Painful obstruction
Usually due to gallstone.
What congenital condition may be found in a small bowel endoscopy? What complications could arise?
Meckel’s Diverticulum
Congenital diverticulum.
- 2ft from ileocaecal valve.
- 2% of population
- 2 inches long (roughly)
Could contain acid secreting gastric mucosa, cause bleeding/ inflammation.
Name some commonly found abnormalities in a colonoscopy.
Diverticula
Cancers - especially in caecum and ascending.
Haemorrhoids etc.
