digestive system part 3 Flashcards
what percentage of the US is affected by peptic ulcers
10%
what is a peptic ulcer due to
gastric juice (HCL and Pepsin) digesting the mucosal lining of GI tract
peptic ulcers is 8-% in duodenum of small intestine and the rest in
stomach and esophagus
peptic ulcers are due to infection with
helibacter pylori
what does helibacter pylori do
destroys mucus layer
what are peptic ulcers linked do
gastritis and gastric cancer
what are contributing factors for peptic ulcers
stress
diet
aspirin
NSAIDs
spcy food
coffee
smoking
alcohol-> stomach acid secretions
who and when cultured h. pylori from stomach biopsies consumed solution and developed gastric inflammation. cured by ABX
1982 and dr barry marshall
symptoms of PUD
gnawing epigastric pain, straight through to back
occurs 1-3 hours after eat, relieved by food
loss of appetite
nausea
frequent burping
weight loss
in pud, stomach wall perforation-> ______->_______
peritonitis-> massive hemorrhage
Dx for PUD
urea breath test, stool antigen and PCR test, upper endoscopy
treatment for PUD
2 week course ABX (clarithromycin, metronidazole, amoxicillin, tetracycline)-> kill bacteria, promote ulcer healing, precents recurrence
active ulcers block what
H2 (histamine) receptors inhibit HCL secretion by blocking histamine effects
PPI is
omeoprazole- prilosec, protonix
is PUD is due to long term NSAID’s what happens
block HCL secretion with proton pump inhibitors or use H2 receptor blockers
you eradicate PUD via
ABX and antacids
how much gastric juiced is produced each day
2-3 L
amount of gastric juice produced is due to
type of food entering stomach
how much gastric juice is secreted due to a typical meal
700 ml
stomach secretion regulation is controlled by
negative feedback loops
what is stomach secretions regulation affected by
nervous and hormonal mechanisms
what do neural mechanisms (in stomach secretion regulation) involve
reflexes in medulla, local reflexes in ENS and higher brain centers
what chemicals messengers are included in stomach secretion regulation
hormones (gastrin, secretin, CCK)
what do chemical messengers do
increase, decrease gastric secretion and stimulates pancreatic secretion
stomach secretion regulation has 3 phases which are?
cephalic
gastric
intestinal
what happens during cephalic phase in stomach secretion regulation
increases stomach secretions in anticipation of incoming food
taste and smell of food, chewing and swallowing, pleasant thoughts of food
what happens in gastric phase
most stimulation occurs, distension of stomach stimulates mechanoreceptors
what happens in intestinal phase
stomach secretion decreases (secretin, CCK due to chyme into duodenum)
process of stomach filling
food enters stomach-> rugae flatten and stomach volume increases up to 20 fold
what does stomach expansion accomodate
large amount of food with little increased pressure until stomach is near max capacity
ingested food mixed with stomach gland secretions forms
chyme
what do mixing waves include
contractions that occur every 20 seconds from stomach body to pyloric sphincter
what occurs during peristaltic waves
occurs less frequently, more powerful and force chyme near stomach periphery to pyloric sphincter
what percent of waves and mixing? and peristalitic
80 mixing
20 peri
the amount of time food remains in stomach depends on
type/ volume of food
liquids pass through within how long
minutes
in stomach emptying complete meal in how long
3-4 hours
what do peristaltic contractions force
small amount of chyme through pyloric opening into dueodenum
peristalctic contractions are also called
pyloric pump
increased motility->
increased empyting
when do hunger pangs begin
12-24 hours after meal
in hunger pangs you have uncomfortable what
sensation due to low BS
without ingestine, reaches max intensity in how long
3-4 days and then weaken
what happens when stomach empty too fast
acidic gastric contents into dudenum and damage lining
what happens when stomach empty too slow
less absorption in intestine and stomach wall damaged by acid
stimulus for motility and secretion=
distension of stomach
increased stomach motility increases what
stomach empyting
in duedenum the CCK inhibits what
gastric motility which reduces rate of stomach empyting
what has the fastes clearance time from stomach in 1 hour
carbohydrates
what takes up to 6 hours to clear from stomach
lipids and proteins
what is protective mechanism against ingestin of toxic or harmful substances
vomiting
vomiting is due to
GI tract irritation
APS travel through what to the vomiting center in medulla
vagus nerves and spinal visceral nerves
reflex initated causing: (7)
- deep breath taken
- hyoid bone and larynx elevated, opening upper esophageal sphincter
- opening of larynx closed
- soft palate is elevated, closing naso and oropharynx connection
- diaphragm and abdominal muscles are forcefully contracted, strongly compressing stomach and increasing intragastric pressure
- LES is relaxed
- gastric contents are forces out of stomach, through esophagus and oral cavity and out
3 parts of small intestine
duodenum
jejunum
ileum
what cells produce mucus
goblet cells
length of small intestine
6m or 20 feet
length of duodenum
25 cm
length of jejunum
2.5 m
length of ileum
3.5 m
accesory glands with small intestine
liver
gallbladder
pancrease
what does the pancreas empty secretions into
duodenum
the small intestine is the site of
digestion and absorption prior to large intestine
there are 3 strucutural modifications which increase surface area , which are
- circular folds
- villi
- microvilli
what are mucosa and submucosa folds that run perpendicular to long axis of GI tract
circular folds
what are fingerlike projections of mucosa, covered by simple columnar epithelium, that contains lacteal
villi
what are cytoplasmic extensions that increase surface area
microvilli
as progress through small intestine what happens
decreased diameter, thickness of wall, # of circular folds, and # of villi
absorptive cells produce
digestive enzymes and absorb digested food
goblet cells produce
protective mucus
grandular cells do what
protext intestine from bacteria
endocrine cells produce what hormones
secretin and CCK
shortest part of small intestine
duodenum
the duodenum curves around what
pancreatic head
the secretions enter duodenum from
liver and pancreas
duodenal (brunners) gland=
mucous glands in submucosa
what has decreased diameter, thickeness of wal and # of circular folds and # of villi
jejunum
what contains peyer’s patch
ileium
ileocecal valce goes from
ileum to cecum (1 way)
small intestine movement has
mixing of chyme and slow propulsion down GI tract
what mixes contents in small intestine
segmentation
what propels intestinal contents in GI tract
peristaltic contractions
contractions move at a rate of
1 cm/ min
3-5 hours chyme from
phylorous to ileocecal junction
