L10 panc and liver Flashcards
LO2: list secs of exoc panc.
exoc portion 90% panc mass.
-acinus prod enz. active eg amylase, lipase. proeases inact eg trypsin, chymotrypsin, elastase, carboxypeptidase- activ in duod, prev pancreatitis.
acinus enzs formed on RER to golgi to condensing vacuoles to conc zymogen vacuoles to rel with stim. zymogen grans- mem bound, cont inact precurs conv in int.
-centroacinar/duct cells prod aq neut compon. isot sol (NA, Cl, K, HCO3 ions).
-termin duct modif sec.
LO3: desc contr of panc biliary sec.
-innerv by ANS. SNS- inhibs. PNS vagus stims-Ach.
maj panc ducts join comm bile, both into duod. sphinct of oddi musc determs if panc and bile sec. ent 2nd part duod- vertic junc mid and hindg.
maj duod papilliarised area tiss arnd lumen. ampulla devata where bile and maj panc duct meet=slight widening of sphinct of oddi.
-acinus stim by vagus and CCK (gastrin fam). hypert/fat detec duod=rel CCK. =enz prod. if panc enz esp amylase high in blood suggs panc dam or pancreatitis with other symps.
-duct cells sec HCO3 stim by secretin. secretin prod by jej S cells if acidic. also by duod cells. inside duct cell- co2 and h2o form h2co3 forms H+ and HCO3-. to lumen by exch with Cl-.
opp alk tide- bicarb to ven drain of stom, rev in panc ven blood. slight decr pH as bicarb to gut lumen, H+ into blood= transient decr pH panc ven blood.
- at high flow rate incr sec HCO3- in duct cells.
LO4: desc mech of alk juice sec.
- duct cells sec alk by active pump HCO3 ECF to lumen. H+ out lumen to blood using energ of Na+ in.
LO5: rel struc endc panc to its secs.
-panc horms by panc islet-
alpha cells sec gluagon.
beta sec insulin.
LO6: desc dig funcs of liv and compons of bile.
-liver- metab, detox, plasma prot prod.
in gut- sec of bile. 250ml-1L/day.
bile= bile ac and alk juice. bile pigm.
- all gut blood drain through liv bef systemic circ through portal vein. Has some O but main func deliv nutr etc from gut. 70-80% blood to liv by portal vein, hepat art rest.
LO7: desc how microsc struc liv relates to its funcs.
-chief func cell= hepatoc. 80% mass. v active- prod prot and lip for export so cont lot s/rER (sER for fat and detox). stacks golgi mems. cont lot glycogen which flucs.
- struc unit- liv lobule. hepatocs div by CT. invag of liv caps. cent vein. portal triads at some vertices= hepat art, portal vein, bile duct drain bile out.
-func unit- acinus. long ais btw cent veins. short btw triads. zone 1 at lobule bound v oxygenat comp to 3, also gets toxins 1st. if hypotension zone 3 hit 1st with isch assault.
-bile canacliculi drain from cent to lobule periph to bigger ones to out hepat duct to biliary sys. some stored in gallb. bile ducts to duod.
-oxy blood hepat art mix deoxy portal vein to cent vein. unite- out hepat veins to VC.
BLOOD IN BILE OUT.
LO8: desc sec bile ac and entero hepat circ of bile ac.
-bile 2 compons-
bile ac dep- sec to canaliculi by hepatoc. cont bila ac and pigm.
bile ac indep- sec by duct cells. simil alk sol to aq compon from panc duct cells. stim by secretin. neut acid chyme.
bile= 61% bile salts. 12% FA. 7% prot. 5% other. 3% bilirubin. 3% Plip. 9% chol.
-2 prim bile ac- gen insol at duod pH so not inv in func of salt. cholic ac and chenodeoxycholic ac- furth bile ac formed in gut.
-bile salts- bile ac are conjug with glycine and aurine. are sol at duod pH. amphipath struc- phillic sol end, phob lip sol end. act at water/oil interface. for emulsif of lip. allow emulsif large struc lip in chyme by break to smaller unit= incr sa for panc lipase.
-entero hepat circ bile ac- reabs and recyc. some lost. bile salt not ent gut epith with lip. stays lumen. reabs in termin ileum back to liv in portal blood where liv extracts. so liv not have to synth tot bile ac reqs.
LO9: desc mechs of dig fat.
-lip tend form large globules by time reach duod. low sa for enz. bile ac emulsif and disperse drops.
bile ac then forms micelles with prods of lip breakd eg chol, monoglycerides, free FA- 1 lay, fat inside for transp through watery med. micelle diff to mvilli bord, prods diff into enterocs, leave bile salts beh.
lip diff down conc grad to int epith then re esterif back to TAG, Plip, chol. then pack with apop chylomic. chylom exoc from basolat mem, too large to ent capill, ent lacteals alongs capill. through LS to re ent circ at thoracic duct- largest LV in bod., gen delivs to L subclav vein. back to R heart.
LO10: desc func gallb and rel to gallst format.
-bile prod const but req intermitt. gallb stores- concs bile by rem water and ions, can = gallst due to precip insol compons.
sphinct oddi closed most time so path least resis to gallb.
gallst formed of constits of bile eg chol, pigm, or mixed.
CCk rel from duod stims gallb contrac- detec hypertonic chyme and fat= relax sphinct oddi. match to reqs.
gallb to duct to cystic duct to comm bile duct.
-streatorr- if bile ac, salts or panc lipase not adeq sec= fat in faeces= pale, float, smell.
-bile pigm- excret prods-
bilirubin- breakd prod of Hb. conjug in liv makes sol. sec to bile. brok down in gut and excret in faeces=brown. accum in blood if cant be excret= jaundice, pale stool, dark urine (as conjug and sol). =block biliary tree eg gallst, panc head CA. gallst in neck gallb or bil tree= bil cholic/obstruc.
func applic liv, gallb, panc.
-cirrhosis-comm cause portal hypert, alc. prog destruc hepatoc= repl by fib tis. surr intrahepat BV and bile ducts and prevs circ. =incr press in veins ent liv= varicosed vains= incr heamorr.
LO1: desc key props of chyme leaving stom.
- slight hypertonic, incr rap as dig. acidic. partly dig.
want isotonic when leave duod so - water from ECF/circ. duod more perm. solute in chyme draws water in, also ion transp.
-sec:
panc- enz and bicarb ions.
liver- bicarb ions and bile.
-hypertonicity- because food prod lot solutes diss in gastric juice. stom wall largely imperm.
-chyme rel must be contr or overwh duod, pH, osmot press etc.
