Case 2 - peptic ulcers Flashcards
what are the three layers of the inner wall of the GI tract
epithelial layer
lamina propria
muscularis mucosa
what does the epithelial layer do
absorbs and secretes mucus and digestive enzymes
what does the lamina propria contain
blood and lymph vessels
what does the muscularis mucosa do
smooth muscle that contracts and breaksdown food
what are the four areas of the stomach
- carida
- fundus
- body
- pyloric antrum
look up a photo
what closes when eating
the pyloric sphincter at the end of the stomach
features of the cardia area epithelial layer
has mostly foveolar cells
these secrete mucus which is made up of water and glycoproteins
features of the fundus and body epithelial layer
parietal cells that secrete hydrochloric acid
chief cells that secrete pepsinogen which is an enzyme that digests proteins
features of the antrum epithelial area
G cells - secrete gastrin
also found in the duodenum and the pancreas
what is the pancreas
an accessory gland to the GI tract
what does gastrin do
stimulates parietal cells to secrete hydrochloric acid
stimulates growth of the glands
where are Brunner glands located and what do they do
found in duodenum
secrete mucus rich in bicarbonate ions
what do bicarbonate ions do
neutralise the acid in the stomach
what has a thicker mucus layer - the stomach or duodenum and why
the stomach walls are constantly exposed to acid and therefore have a thicker mucus layer but in the duodenum, they are only momentarily exposed to acid and therefore have a thinner layer
what also neutralises the hydrochloric acid
the blood coming to the stomach brings more bicarbonate
what do prostaglandins do
stimulate mucus and bicarbonate
vasodilate nearby blood vessels and therefore more blood flow and therefore more epithelial cells growth
it also inhibits acid secretion
what is H.pylori
gram negative bacteria
colonize in gastric mucosa
what does h.pylori release
releases adhesions which helps them adhere to the gastric foveolar cells
also proteases which cause damage to mucosal cells
where does the damage usually start
usually starts in the antrum and then spreads to the rest of the stomach and then eventually into the duodenum
what do NSAIDs do
inhibit COX synthesis of inflammatory prostaglandins
leaves gastric mucosa susceptible to damage
what is Zollinger-Ellison syndrome
tumour -> gastrinoma
Neuroendocrine tumour in duodenal wall or pancreas
Secretes abnormal amounts of gastrin
This leads parietal cells to release excess hydrochloric acid
what are some of the features of ulcers
small ‘punched out’ holes in mucosa
Clean base
Scar tissue
Ulcers can bleed if erosion goes deep
what can very deep ulcers cause
can cause bleeding
what could happen if the ulcer is in the antrum
cause bleeding in the left gastric artery
