GIT Flashcards
3 regions of the stomach
cardiac region - surrounds the cardiac orifice
body - midportion of the stomach
pyloric region - made up of the antrum and canal which terminates at the pylorus
Secretory cells of the gastric glands
chief cells - pepsinogen
parietal cells - HCl and intrinsic factor
mucous neck cells - mucous
enteroendocrine cells - secrete gastrin
Regulation of Gastric secretion
cephalic phase: central cortex, sight smell thought of food
Gastric phase: as food enters, stomach distension, reflexes, chemical and hormonal stimuli
Intestinal phase: low pH in stomach releases intestinal hormones (cholecystokinin and secretin)
Name the 4 accessory structures
salivary glands
liver
gall bladder
pancreas
Function of salivary glands
cleanses the mouth
moistens and dissolves food chemicals
aids in bolus formation
enzymes secretion that break down starch (amylase)
Function of Liver
produces bile
cleanses and detoxifies - anything that is ingested goes through the liver
COMposition of bile
bile salts
pigments
cholesterol
lecithin
Gallbladder function
stores extra bile
Pancreas function
secretes digestive enzymes
regulation of bile secretion both hormonally and chemically
disorders of motility
dysphagia gastroeosophageal reflux oesophageal diverticulum hiatal hernia pyloric obstruction
Dysphagia
difficulty swallowing
mechanical or functional obstruction of oesophagus
reduced muscle tone and peristaltic function, reduced food in stomach
Gastroesophageal Reflux
regurgitation of chyme from stomach into oesophagus
Can result in inflammation due to repeated exposure to acids and enzymes
symptoms of gastroeosophageal reflux
oedema
erosion
ulceration
Oesophageal diverticulum
outpouching of the oesophagus
food may be trapped
can lead to dysphagia and regurgitation
hiatal hernia
protrusion of upper part of stimach through hiatus at GI junction
sliding: congenital short oesophagus, trauma, weak diaphragmatic muscles
paraoesophageal: greater curvature of stomach herniates alongside oesophagus, creates a small balloon on its own
pyloric obstruction
narrowing or blockage of pylorus (between stomach and duodenum)
causes of pyloric obstruction
congenital defect
tumour
peptic ulcers
symptoms of pyloric obstruction
epigastric fullness
nausea
epigastric pain
Malabsorption syndromes (3)
pancreatic insufficiency
lactose enzyme deficiency
bile salt deficiency
Pancreatic insufficiency
insufficient enzyme production of CHO, ,fat and protein digestion
fat maldigestion leads to fat in stools
absence of HCO leads to reduced pH which prevents activation of pancreatic enzymes
lactose enzyme deficiency
inhibits lactose breakdown into mono-CHO which prevents lactose digestion and absorption
bile salt deficiency
bile salts necesary for fat digestion
causes fat malapsorption and steotorrhea
Gastritis
inflammation of gastric mucosa
acute: superficial erosions
chronic: thinning and degradation of stomach wall
types of gastritis
fundul: degeneration of fundus and stomach mucosa
antral: caused by helicobactor pylori bacteria
Peptic ulcers
acidic component that is causative in the disease progression
mucosal ulceration of stomach or duodenum
risk factors of peptic ulcers
smoking, alcoho, RA, cirrhosis, anti-inflammatory drugs, h.pylori, NSAIDS, aspirin
types of peptic ulcers
duodenal
gastric
stress
duodenal ulcers
increased gastrin which increases HCl production
symptoms: collicky, pain when stomach is empty
gastric ulcers
developed in antrum of stomach
gastric secretion normal or reduced
pain after eating
stress ulcers
develops after stress/trauma due to ischaemia
ischaemic: develops hours after heamorrhage
cushing: develops from reduced blood, increased HCl production