Stomach Flashcards
what level does the oesophagus come through the diaphraghm
T10
regions
epigastric, umbilical (sometimes), left hypochondriac
where do the omentums hang from
greater = greater curvature
lesser = lesser curvature
what happens when the stomach dissents
stimuli is sent to the hypothalamus where the hunger centre controls the desire to eat
lesser curvature
stomach and the liver connected by the hepatic gastro ligament
ascends to attach to the liver
attaches stomach and duodenum to liver
R & L gastric arteries and superior gastric lymph nodes
greater curvature
stomach to the spleen via gastro-splenic ligament
hangs down attaching to the transverse colon
gastric vessels and inferior gastric LN
four regions
fundus
body
neck
cardia
fundus
lies below the diaphragm dome, rounded often filled with gas
body
lies below the fundus and above pyloric atrium
makes up 2/3 junction is indicated by the angular notch
pylorus
connects to duodenum, pyloric antrium, pyloric canal and sphincter @ T1
cardia
reciences GOJ signifies opening @T11
anterior relations
diaphragm
intercostal margin
left lobe of liver
gall bladder
ant abdominal wall
right lateral relation
duodenum
liver
left lateral relation
spleen
diaphragm
posterior relations
stomach bed
diaphragm
left adrenal gland
left kidney
spleen
pancreas
splenic artery
AA
splenic flexure of colon
left half of transverse colon
transverse mesocolon
superior relations
oesophagus
diaphragm
left liver lobe
diaphragm presses on the oesophagus preventing regurgitation of gastric contents
inferior oesophageal sphincter marks the transitional point between the oesophagus and stomach
oesophagus joins the cardiac orifice at T11
inferior relations
SI
transverse colon
what does the pyloric sphincter do
control the exit of chyme, when there’s food in the stomach the pylorus contact so that the orifice is small
peristalsis pushes chyme through the pyloric canal into the duodenum
gastric juice
mineral salts
water = liquidify food
mucus neck cells = protection
chief cells = pepsinogen, breakdown of proteins
parietal cells = HCl promote the action of pepsin, stops salivary amylase, it has an intrinsic factor = absorption of B12
blood supply
gastric arteries, branches of the hepatic and splenic arteries
gastric veins (L or R) -> hepatic portal vein -> IVC (drains into portal circulation)
nerve supply
parasympathetic: vagus nerve
sympathetic: coeliac plexus
vagus = increase in motility, secretion of GJ and peristalsis, increasing digestion rate
coeliac = slowed down digestion, sphincters close, peristalsis reduced
lymphatics
gastric lymph vessels travel with the arteries along the lesser and greater curvature, lymph drains into the sup and inf gastric nodes
coeliac nodes = infront of AA
cisterna chyli -> thoracic duct -> heart
LN
coeliac, splenic hilar, porta hepatis, gastroduodenal, supra-pancreatic
four layers of stomach
outer serous layer
smooth muscle
sub mucous membrane
mucous membrane
outer serous layer
visceral peritoneum, covers surface not fundus
smooth muscle
outer = longitudinal
inner = circular muscle fibres
inner incomplete layers of obliquely arranged smooth muscles
submuscous membrane
loose areolar tissue, connecting membrane with vessels and nerves
mucous membrane
empty stomach = longitudinal folds aka rugaae
as the stomach fills, the rugae flatten and become smooth
gastric pits extend down
columnar epithelium with large amounts of gastric glands
cardiac glands
near cardiac orificie secreting mucus
body glands
secreting gastric juice at the body
pyloric glands
pyloric antrium, secreting mucus
mucus neck cells =
mucus
parietal cells =
HCl
chief cells
pepsinogen (gastric precursor)
enteroendocrine cells
gastrin goes into the blood which stimulates the gastric glands to produce gastric juice
mechanical digestion
peristalsis passes along the body and pyloric antrium
pyloric sphincter closes, constriction of stomach causes churning mixing of the gastric juices
sphincter opens and small amounts pass into the duodenum
mucus from the cardiac, body, fundus and pyloric glands lubricate the food passage and portent against digestive enzymes
what hormone does the stomach secrete
gastrin
chemical digestion
gastric juices secreted from the fundus and body gland are initiated by the vagus never as a reflex response to the thought and smell of food
it is increased further by neural stimulation in response to pressure of food and hormone stimulation by gastrin
HCl role
kills pathogens = protection
vomiting is due to ingesting gastric irritants
what function is limited
absorption of water, glucose, salts
the components of gastric juice
HCl acidified stomach contents
pepsinogen -> pepsin (1.5-3.5 optimum)
pepsin initates the break down of proteins into peptones
renin converts caseinogen into insoluble proton casein
intrinsic factor for B12 absorption in the terminal ileum
how does the stomach prepare Fe absorption
acid solubilises Fe salts, essential for absorption in the SI
what happens when the pylorus forces GJ
regulation of gastric juices in the duo
chyme is acidified and liquified
what are the three secretion phases
coeliac
gastric
intestinal
coeliac phase
parasympathetic stimulation causes secretion before food is reaches the stomach via the vagus nerve, initated by smell, sight or taste
once the nerves stop, the secretions stop
sympathetic stimualtion inhibits gastric activity
gastric phase
stimulated by food, the enteroendocrine cells in the pylorus and duodenum secrete gastrin, which circulates the blood stream. the glands are stimulated which produces gastric juice, secretions are suppressed when ph falls to 1.5
intestinal phase
secretin and cholecytoskinin are produced by endocrine cells, in the intestinal mucosa, slowing down GJ secretions, reducing motility
emptying rate slows down allowing chyme to be mixed with bile and pancreatic juice
what is the rate of emptying dependent on
food type
carbs empty the fastest then proteins then lipids
