Gastrointestinal Disorders (Exam 2) Flashcards
diarrhea
passage of abnormally liquid or unformed stools at an increased frequency
causes of diarrhea
microbial infections
medications
food related
abrupt onset of chronic disease
functions of the GI system
assimilation of nutrients
excretion of waste products
endocrine, immune, barrier functions
control over multiple processes and organs is provided by
enteric nervous system
hormones
assimilation of nutrients includes
motility of food
secretion of fluid and enzymes for digestion
absorption of nutrients
transport of nutrients into circulatory system
layers of the GI from inside to outside
Mucosa
Submucosa
Muscularis externa
Serosa
mouth
chewing, mixing with saliva, bolus formation
stomach
1-4 hours transit time
mix, grind, dilute and dissolve food
exocrine secretions, gastric acid and intrinsic factor
level of absorption in the stomach
minor
gastric emptying
key control point for further delivery and indicating satiety
cells in the stomach
parietal cells
cheif cells
enteroendocrine cells
mucous neck cells
parietal cells
produce HCl and intrinsic factor
chief cells
produce pepsinogen
enteroendocrine cells
produce hormones
gastrin in stomach
peptide hormones in small intestine
mucous neck cells
produce thin, acidic mucus
small intestine
7-10 hours transit time
continues digestion of proteins, fats and carbohydrates
receives digestive secretions from the liver and pancreas
produces enzymes, alkaline mucus
produces hormones
how much absorption occurs in the small intestine
90% (she works like a dog DAY AND NIGHT SIPPING FROM A POT NONE OF YOU WANT TO TOUCH!!!)
cells in small intestine
enterocytes
enteroendocrine cells
paneth cells
goblet cells
goblet cells
produce thick mucus
paneth cells
produce antimicrobial peptides
enterocytes
absorb water and nutrients
intestinal stem cells and migration of their progeny occurs from
crypt to villus
regenerates every 4-5 days
endocrine pancreas
regulating metabolism
produces and secretes hormones
what is secreted from endocrine pancreas and what do they do?
insulin - glucose uptake from blood
glucagon - breakdown glycogen to glucose
somatostatin - growth hormone inhibiting hormone; regulates endocrine system
exocrine pancreas
digesting food
produces and secretes enzymes
what is released from the exocrine pancreas?
proteases
lipase
amylase
enzymes are produced in the
inactive form (zymogen) and only activated when released
prevents self digestion of the pancreas
pancreas duct cells
produce and secrete bicarbonate
neutralize stomach acid
liver functions
prepares food for digestion in the SI
detoxifies blood from GI
regulates metabolism of biomolecules
produces plasma proteins
produces fats, lipids and cholesterol
gallbladder
stores and releases bile
large intestine
12-24 hrs transit time
water and electrolyte absorption
microflora process undigested food
storage of fecal waste
rectum and anus
elimination of fecal waste
1-3 days after meal ingestion
large intestines only have
crypts
NO VILLI!!!!
the small intestine has
both crypts and villi (because she does the hard work, needs more assistance)
what is the difference in cells in epithelium of the small and large intestines
large intestines do NOT have paneth cells
sphincters
help control over assimilation of nutrients
neural regulation
control over intestinal secretions and smooth muscle activity in intestinal wall and blood vessels
endocrine regulation
release of hormones into the bloodstream triggered by a meal
paracrine regulation
release of substances that alter nearby cells
neuronal signaling controls
digestion
fluid secretions and absorption
motility
blood flow
the enteric nervous system controls
every part of the GI tract
hormones in the GI coordinate
movement
secretions
digestion of food
absorption of nutrients
brain responses
peristalsis
propels contents orally to caudally
circular contraction behind contents
segmentation
forces the contents back and forth to mix
fluid and electrolyte balance
fluid ingested and secreted must equal fluid absorbed + fluid exerted
the ability to absorb 9.3 liters is due to the function of
several transport proteins
transport of Na across intestinal epithelium drives
simultaneous absorption of water into tissue by osmosis
transport of Cl across intestinal epithelium drives
simultaneous secretion of water into gut lumen by osmosis
mucosal immune system
recognizes pathogenic microbes, commensal microbes and foods
70% of immune system cells are in the GI tract
nausea
inclination to vomit or feeling in the throat alerting that vomiting is coming
vomiting
ejection/expulsion of gastric material through mouth, forcefully
regurgitation
gastric/esophageal contents rise to pharynx but no forceful ejection
symptoms of N&V
pallor, tachycardia, sweating
emetic
capable of inducing vomiting
Therapy induced causes of N&V include
antineoplastic agents (chemotherapy)
3 stages of emesis
- nausea
- retching
- vomiting
retching
labored movement of thoracic and abdominal muscles before vomiting
vomiting is coordinated
by the brainstem
vomiting requires
contractions of abdominal muscles, pyloric, antrum
raised gastric cardia
diminished lower esophageal sphincter pressure
esophageal dilation