gastrointestinal system Flashcards
27: processing of food steps
motility secretion digestion absorption excretion
27: three key stages of gut regulation
cephalic
gastric
intestinal
27: saliva functions
lubrication
digestion (amylase, R proteins)
solution
protection
27: salivary glands (3)
parotid - shroud, amylase
sublingual/submandibular
minor glands
27: salivary gland structure - acinus
primary secretion
isotonic
plasma like
27: salivary gland structure - duct
secondary modification
low h20 permeability
27: saliva fluid secretion- primary fluid
isotonic
plasma like
27: saliva fluid secretion- secondary ductal modification
na+ and cl- reabsorption
k+ and HCO3- secretion
27: saliva fluid secretion - final saliva
hypotonic
HCO3 - rich
27: control of salivation - cephalic phase
- sight
- smell
- taste
27: control of salivation - parasympathetic(cholinergic)
- cranial nerves VII and IX
- large volume
27: stomach - gastric functions
digestion
control gastric emptying
protection
27: what is SA of the stomach increased by
gastric pits
27: composition of gastric juice
- HCL
- pepsinogen to pepsin
- mucus and bicarbonate
- intrinsic factor
27: parietal cells secretion, stimulus and function
secretion - gastric acid (HCL)
stimulus - acetylcholine, gastrin, histamine
function - kills bacteria, denatures protein, activates pepsin
27: chief cells secretion, stimulus and function
secretion - pepsin, gastric lipase
stimulus - acetylcholine
function digest protein (p) and fats (gl)
27: ph at which pepsin is inactivated and denatured
pepsin inactivated at >ph3.5
denatured at >ph7.2
27: g cells secretion, stimulus and function
secretion - gastrin
stimulus - acetylcholine, peptides and aa
function - stimulate gastric acid secretion
27: d cells secretion, stimulus and function
secretion - somatostatin
stimulus - acid in stomach
function - inhibition of gastric acid secretion
27: enterochromaffin like cells (ECL) secretion, stimulus, function
secretion - histamine
stimulus - acetylcholine, gastrin
function - stimulates gastric acid secretion
27: cephalic phase - vagal efferent nerves
direct effect
histamine release
gastrin release
27: control mechanisms - gastric phase
good in stomach
gastrin releases
negative feedback inhibition
27: control mechanisms - intestinal phase
inhibitory
28: pancreatic juice - where is primary secretion from
acing cells
28: pancreatic enzyme - carbohydrate digestion
amylolytic
- amylase
28: pancreatic enzyme - protein digestion
proteolytic
- trypsin, chymotrypsin, elastase
28: pancreatic enzyme - nuclei acid digestion
nucleoltyic
- DNAse, RNAse
28: pancreatic proteases
secreted as zymogens
28: pancreatic proteases - trypsin inhibitor
block activity of trypsin
28: pancreatic HCO3- secretion: acing cell primary secretion
isotonic NaCl secretion
28: where is HCO3 - secreted form
pancreatic duct cell
28: rustic fibrosis - lacking channel
CFTR
28: pancreatic secretion - secretion
- duodenal S cells
- increase HCO3 - rich secretion
28: pancreatic secretion - cholecystokinin pancreozymin
- duodenal I cells
- stimulate gall bladder contraction and pancreatic enzyme secretion
28: pancreatic secretion - neural (vagus)
stimulate acinar cells and duct cells
28: bile functions
eliminate waste product s
promote lipid digestion and absorption
28: bile lipids
bile acids
phospholipids
cholesterol
28: bile pigments
bilirubin
28: bile acids - primary
liver synthesis from cholesterol
28: bile acids - conjugation
conjugation to amino acids
increases solubility
28: why do biles last coat lipids
emulsions
28: emulsification of dietary lipids increases …
SA exposed to lipases which promotes digestion
28: functions of gall bladder
concentrates bile
absorbs electrolytes
isotonic
28: control of binary secretion - ductal
secretin
28: control of biliary secretion - gall bladder contraction
CCK
ACH (vagal nerves)
28: gallstones result of
failure to keep cholesterol in solution
29: 3 sections of the small intestine
duodenum
jejunum
ileum
29: small intestine electrolyte absorption
NaCl
29: small intestine secretion
fluid
NaCl
Crypts
29: luminal digestion of starch type polysaccharides
amylases
29: where are monosaccharides absorbed
small intestine
29: polysaccarides - enzymes - digestion products
starch + glycogen - amylase - dextrins
cellulose - colonic bacteria - organic acids/gas
29: disaccharides - enzymes - digestion products
sucrose - sucrase - glucose + fructose
lactose - lactase - glucose + galactose
maltose - maltase - glucose + glucose
29: carbohydrate absorption at apical membrane
SGLT1 (glucose and galactose via secondary active transport)
GLUT (fructose via facilitated diffusion)
29: carbohydrate absorption at basolateral membrane
GLUT2 via facilitated diffusion
29: luminal digestion by
gastric and pancreatic proteases
29: protein digestion - gastric pepsin
endopeptidase
29: protein digestion - pancreatic peptidases
endopeptidases and exopeptidase
29:protein digestion - membrane and systolic peptidases
endo, exo or dipeptidases
29: amino acid absorption - types of amino acid transporters
neutral
cationic
anionic
29: dietary lipids
triglycerides
phospholipids
short chain fatty acids
29: lipid digestion stages
- emulsification
- digestion (gastric/pancreatic enzymes/colipase)
29: lipid absorption
diffusion down gradient
driven by resterifictaion of fattya acids to triglycerides