L11 dealing with toxins

Question 1

LO2: desc defs mechsm in GIT to deal with toxins.

Answer 1

INNATE- phys.

• sight, smell, mem
• saliva- 1.5l/d, most swall and reabs. pH7 not dam teeth. lysosome hole gram pos, lipoperox gram neg. complem. IgA sec to gut/RT. polymorphs. washes tox to stom.
• gastric ac. would= ulcer w/o mucus. 2.5l gastric sec/d. pH down to 0.87. mTB resis (ac and alc fast bact AAFB) so gastric wash diag. H pylori urease =NH3 from urea. enterovirs eg hep A, polio, coxsackie, noro.
• small int sec 4.5l/d. colon mucus ESSEN. anaer envs. small int us no bact as bile, proteolytic enzs, lack nutr, anaer, shedd epith, peristal. colon lot flora, faeces 40%, mucus protec. peristal/segm- norm int transit 12-18hr, if slow= prolong gut infec eg shigelloisis.
• oesoph- flow liq and peristal.

Question 2

LO3: desc conseqs of def fail.

Answer 2

-sev illn/dehyd= decr saliv flow=xerostomia=microb overgrowth and dent caries. can= parotitis- S aureus ent whartons duct, 25% mort today, tight fascia= swell and pain.
xerostomia- dry, candida infec, black hairy tongue fung.
-stom ac fail- achlorhydria not prod ac due to eg pernic anaem, H2 antag, PPis. = incr suscep to shigellosis, chol, salmonella. C.diff in hosp PPI.
-tonsils fail= sore throat and cervic llymphadenopathy v comm. most due to adenovir, minority bact eg strep viridans and pyogenes.
-PP fail= mesent adenitis- comm cause RIF pain kids, simil append, cause us adenov/coxsackie. inflamm mesent LN.
typhoid fever- inflamed PP termin ileum can perforate and kill.
-appendicitis- from myphoid hyperplasia at base=obstruc outflow, anaer stasis and infec. purilent (bact) cause appendicitis more comm dur chicken pox epidemics in kids as vir= LT at base enlarge, bact attr and prolif. also cause by faecoliths and worms.
-chem tox mod, hum not resis yet eg metalloids, metals, solvents, drugs. so lead, Al, mercury etc toxic. arsenic- unsafe levs Bangladesh tube wells, organ fail, hand dam.
-gut isch- GIT def req blood supp. int/hepat isch due to art dis,systemic hypot, or int ven thrombosis. freq= overwh sepsis and rap death. decr gut perfus= decr mucus. comm fatality in ICU.

Question 3

LO2:

Answer 3

INNATE cellul: neur, mac, NK, mast, eosin.
- neutroph- to gut from blood. superox format kill bact. polymorphonuc. trap bact. cant kill worms.
- eosin- grans cont: perforins hole mem, peroxidases, cationic prots, maj basic prots. eosinophilia feat of- asthma, hayfever, parasitic infec.
parasitic infec: antihelminth. guinea worm ghana sudan.
-circ basoph- become mast in tiss eg gut. grans histam. gut infec that activ complem eg chol rec mast, rel histam=vasodilat and incr capill perm= mass fluid loss, chol 1l/hr, 60% mort untreat.
-NK mig to gut, hole in bact.
-mac- circ monoc to tiss mac. phagoc to phagos to lysos kill by oxid activ, expell. lot lung, spleen, liv.

Question 4

LO4: role of liv in handling bile pigm, horms, drugs and toxins.

Answer 4

-liv dis incr due to alc and obes. most nutr and tox abs SI. colon norm full bact- mucus fail=bact to ven drain to SMV joined by spleen=port vein. to liv to rem tox from GIT so not distrib rnd bod.
-portal sys in bod- 2 capill sys in series-
hepat port sys largest. hypothalamo-hypohyseal port sys convey horm hypoth to pit.
villus link by port vein to hapat lobule. microbes out and flow out in bile canaliculi. kupffer mac in sinusoid wall.
-liv fail- vir hep, alc, drugs eg paracetamol and halothane, indust solvents, mushroom pois.
incr suscep to infec- 80% bact, also fung. high mort. incr suscep to tox, drugs, horms. incr blood nh3 as fail clear via urea cyc. nh3 prod by colonic bact and demain aa= hepatic enceph, incr comm.

Question 5

LO5: how liv dis= portal hypert and its assoc pathol.

Answer 5

-cirrhosis= heapt fibrosis. shrunken, hard. early stages enlarged liv and spleen as port tens. hepat fib= port ven hypert- vains not drain prop, incr press in leaving veins so blood can go from port ven circ direc to norm circ= portosystemic shunt. so toxin shunt. = oesoph varices, haemorrh, caput medusae.
-ano rectal junc- in most of gut veins sit ons serosa outs, at anorectal junc and gastro oesoph junc veins inside submuc so incr abdo press= incr vein size=mucosa pushed togeth=swell prev anyth pass. if port cven hypert veins full blood at high press= oesoph varices or haemorrh- dang if bleed.
caput medusae- if PVH- L umb vein opens, blood to umb. paraumb veins that carry O blood from mum to fetus, norm close fater birth recanal due to hypert. blood up from umb and down from.
also occ if IVC occlus above. drain lower limbs not get in so open other ven paths abdo wall. blood all up.

Question 6

LO2:

Answer 6

ADAP DEFS:
cellul- B lymphoc prod Ab incl IgA+E partic eff ag EC microbes. T lymphocs ad intracell.
LT- mucosl assoc lymphat tiss/ GALT- diffusely distrib but nodular in 3 locats:
-tonsils- lingual back tongue, palatine, nasophar (adenoid). conjug LT. drain to cervic LN.
-PP- lymphoid follic come up to just below surf.
ileocecal LT- valve prev mater wrong way. incompet valve= colon bact to ileum, less mucus. so have PP termin ileum below muc.
-appendix- lot LT through length. lymphat nodules.

Question 7

LO1: desc range toxins GIT and liv exposed to.

Answer 7

-chem
bact
vir
protoz
nemat (roundworm)
cestode (tapeworm)
trematode (flukes)