week 1 Flashcards
(24 cards)
What are the different parts of the stomach?
Cardia fundus body antrum pyloris
Describe the cells in the cardia of the stomach
Branching mucosal cells without parietal cells
Describe the cells in the fundus of the stomach
Straight glands composed of tightly packed chief cells, parietal cells, endocrine cells and mucous cells
Describe the cells in the antrum of the stomach
Branching mucous glands
may contain small aggregates of lymphocytes
Describe parietal cells
mainly in the fundus / body of the stomach
Stimulated by vagus nerve, gastrin binding and histamine binding
What are the secretions of the endocrine cells in the stomach?
Gastrin, seratonin and somatostatin
What is the role of ECL cells?
release histamine in response to gastrin
Describe the histology of the duodenum
Mucosa is lined by simple columnar epithelium, mainly absorptive cells (enterocytes), with some goblet cells and occasional enteroendocrine cells.
The main feature unique to the duodenum is the presence of Brunner’s glands, which secrete bicarbonate to neutralise stomach acid.
What is the basal electric rate?
The maximum number of contractions that can occur in a minute
In the stomach it is 3/min
What will acid in the duodenum stimulate?
secretin release
What does the release of secretin do?
inhibits gastrin and therefore inhibits stomach motility
What do fats in the duodenum stimulate?
release of CCK and GIP
What do CCK and GIP do in the stomach?
Inhibit motility
What does GORD stand for?
gastro-oesophageal reflux disease
What are the symptoms of GORD?
heart burn
regurgitation
epigastric pain (dyspepsia)
nausea
What protective mechanisms are normally in place to protect the oesophagus from acid?
intrinsic sphincter extrinsic sphincter intra-abdominal oesophagus angle of His/FLap valve secondary peristalsis
What can lead to GORD?
hiatus hernia transient lower oesophageal relaxations low sphincter pressure impaired oesophageal clearance increased intra-abdominal pressure reduced gastric emptying
What is a hiatus hernia?
protrusion of part of the stomach through the diaphragmatic hiatus and into the chest
What are red flag symptoms for GORD?
unexplained weight loss dysphagia persistant vomiting evidence of GI blood loss upper abdominal mass
Describe swallowing
food bolus pushed up against soft palate and into pharynx
UES relaxes, respiration pauses, glottis closes
Primary peristaltic wave propels bolus towards stomach
Secondary peristalsis occurs locally in response to distension
What is oesophagitis?
inflammation of squamous mucosa.
secondary to acid damage
can cause stritures
What is Barrett’s oesophagus?
columnar transformation of squamous mucosa caused by chronic acid damage
What is adenocarcinoma?
accumulating cellular genetic changes causing dysplasia and ultimately cancer
How do PPIs work?
Accumulate selectively in the acid cannaliculi of parietal cells
undergo acid-catalysed rearrangement to active drug
Cationic sulfenamide binds irreversibly on the proton pump causing inhibition
