Sinh lý bệnh thú y

1 I HC THI NGUYN TRNG I HC NNG LM PGS. TS. NGUYN QUANG TUYN - ThS. TRN VN THNG

GIO TRNH SINH L BNH TH Y (Gio trnh dng cho h i hc) NH XUT BN NNG NGHIP H Ni - 2007 2 LI NI U Gio trnh Sinh l bnh th y c bin son p ng vi nhu cu cp thit v ti liu hc tp ca sinh vin ngnh Th y trong cc trng i hc thuc khi Nng nghip, cng nh nng cao cht lng ging dy v hc tp khi p dng phng php ging dy mi. Sinh l bnh hc l mn hc nghin cu v nhng thay i chc nng ca c quan, m v t bo khi c thm bnh, ng thi l mn hc tin tm sng ca ngnh Th y v cu ni gia cc mn hc c s nh sinh l hc, sinh ha hc, vi sinh vt hc v cc mn hc lm sng nh bnh ni khoa, bnh k sinh trng, bnh truyn nhim, bnh sn khoa... Cng vi mn Gii phu bnh hc, mn Sinh l bnh hc h thng hoa kin thc cho cc sinh vin ngnh Th y v cn b nghin cu th y v cc quy lut chung ca qu trnh sinh bnh ng vt, cc bin i bnh l ca qu trnh sinh bnh trong c th, s thay i ca cc m bo, t bo, c quan, h thng do ri lon chc nng... ng dng trong cng tc chn on, phng chng bnh cho vt nui, gp phn nng cao hiu qu chn nui v thc y ngnh chn nui pht trin. Bin son gio trnh ny, chng ti c gng th hin tnh c bn, tnh khoa hc, tnh hin i v tnh h thng ca chng trnh mn hc, ng thi c lin h thc tin nhng do trnh v kh nng c hn nn kh trnh khi nhng thiu st. Chng ti rt mong nhn c nhng ng gp kin ca ng nghip v bn c trong qu trnh s dng ti liu ny. Xin chn thnh cm n! Tp th tc gi 3 Bi m u NI DUNG V PHNG PHP NGHIN CU MN SINH L BNH TH Y 1. NH NGHA MN HC Sinh l bnh (PHthophysiology) theo ngha tng qut nht l mn hc v nhng thay i chc nng ca c th, c quan, m v t bo khi chng b bnh. Sinh l bnh hc l mt mn khoa hc nghin cu nhng hot ng ca s sng trong c th bnh, c th l nghin cu nhng bin i bnh l v c nng cc c quan, h thng v m bo, ng thi nghin cu nhng nguyn nhn, iu kin gy bnh v tm ra quy lut chung ca s pht sinh, pht trin v kt thc ca qu trnh bnh l. Mn sinh l gia sc nghin cu tt c c nng, h thng trong c th gia sc (ng vt) bnh thng v tm ra c quy lut nht nh, cng nh vy trn c th bnh

chng ta cng nghin cu tun t v so snh li vi quy lut bnh thng thy c nhng thay i nh th no v t rt ra kt lun vi tng trng hp. Chnh v vy ngi ta thy mi mt bnh c mt quy lut ring v n cng c nhng biu hin bnh l chung. V d: Trong tt c cc loi nhim khun chng ta u thy cc qu trnh bnh l nh vim, st, khi kim tra mu thy bch cu tng v l nhng quy lut chung. Trong khi bnh dch t ln chng ta thy c th ln st, vim nhng bch cu h; bnh lao phi chng ta li thy c th vt bnh st lin min, thng hay st vo bui chiu, ra mi hi nhiu v l nhng quy lut ring. Nhng quy lut ring to nn nhng bin i trn c quan, t chc gi l qu trnh bnh l in hnh v cc qu trnh ny to nn bnh tch in hnh. T nhng quy lut khi qut li v nu ln quy lut hot ng ca tng bnh, to c s l lun cho cc mn hc lm sng tm bin php khng ch. 2. NI DUNG MN HC Ni dung ca mn sinh l bnh hc c chia lm ba chng: Chng 1 : Cc khi nim v quy lut chung v bnh Bao gm: khi nim v bnh, nguyn nhn gy bnh, sinh bnh hc, c tnh ca c th i vi s pht bnh (bnh l ca qu trnh min ch). Chng 2: Sinh l bnh cc qu trnh bnh l chung Bao gm: ri lon tun hon cc b, ri lon chuyn ha cc cht, vim, ri lon iu ho thn nhit, qu trnh bnh l ca s pht trin m bo. Chng 3: Sinh l bnh cc c quan, h thng Nghin cu ri lon chc nng ca cc c quan, h thng: h thng mu v c 4 quan to mu, h tun hon, h h hp, h tiu ha, h tit niu v h thng thn kinh. Vi nhng ni dung trn mn sinh l bnh hc l mn hc c s ca ngnh th y, c lin quan cht ch vi nhiu mn hc khc nh: sinh l gia sc, sinh ha hc, dc l hc, vi sinh vt hc v cc mn lm sng th y nh: bnh ni khoa, chn on bnh, bnh k sinh trng, bnh truyn nhim, bnh sn khoa... c bit sinh l bnh v gii phu bnh l hai cu thnh ca mn Bnh l hc, l hai mn hc c cng chung mt i tng nghin cu nhng sinh l bnh ch yu nghin cu nhng bin i v c nng, cn gii phu bnh th nghin cu nhng bin i v hnh thi trn c th bnh. 3. PHNG PHP NGHIN CU MN SINH L BNH TH Y Phng php nghin cu ca mn sinh l bnh hc l phng php thc nghim, mt phng php rt khch quan v khoa hc. Phng php ny tin hnh gy bnh nhn to trn c th ng vt, sau quan st ton b qu trnh din bin ca bnh, cui cng phn tch v rt ra quy lut chung ca qu trnh bnh l. Trong phng php thc nghim, thng s dng hai phng php l phng php thc nghim cp tnh hay cn gi l cp din v phng php thc nghim mn tnh hay cn gi l trng din. 3.1. Phng php thc nghim cp tnh (cp din) Phng php ny thng phn tch cc chc nng ca cc c quan ring bit, c khi c lp ra khi c th nghin cu, tc l lm nhanh c kt qu ngay c th nm c cc quy lut Ngi ta thng s dng phng php ny trong mt s trng hp chn on nhanh v dng ging dy cho sinh vin. V d: Ngi ta thng c lp tim ch hoc c lp mt on rut nghin cu.

u im: phng php ny tng i n gin, quan st bin i v c nng trong mt thi gian ngn. Nhc im: Gy tn thng trn c th bnh, kch thch tng c quan ring bit mt cch nhn to, thm ch cn tch ri mt s c quan khi c th hoc tin hnh nghin cu di iu kin gy m. Trong nhng iu kin thc nghim nh vy th khng th biu hin c bn cht ca bnh mt cch y , kt qu thu c khng st so vi khi con vt hot ng bnh thng. 3.2. Phng php thc nghim mn tnh (trng din) Phng php thc nghim mn tnh do Pp-lp ra. Phng php ny tin hnh trn con vt sau khi c phu thut v hon ton hi phc, c th con vt trng thi tnh to gn nh bnh thng. V d: ngi ta lm mt ng hng dch v d dy, lm mt ng hng nc bt. 5 - u im: Lm th nghim trn con vt trng thi bnh thng nghin cu c lu di, chnh xc hn, c th rt ra nhng quy lut bin i c th bnh mt cch ton din trong sut qu trnh bnh l, tn t ng vt th nghim. - Nhc im: Ch p dng nghin cu trong mt s trng hp c thi gian nghin cu lu di. Nhng ngi ta thng kt hp c hai phng php trn nghin cu qu trnh bnh mt cch ton din hn. Ngy nay c nhiu phng php nghin cu tin tin nh: phng php ni soi, hoc phng php ct lt b c xem c u no khng, phng php dng my siu m kim tra hot ng ca thai... cng c p dng trong nghin cu sinh l bnh. Ngoi ra sinh l bnh hc cn ng dng nhng thnh tu v phng php mi nht ca khoa hc nh: min dch hc, sinh ha hc, phn t hc (nui cy en, ct en) nghin cu cc qu trnh bnh l. 6 Chng 1 CC KHI NIM V QUY LUT CHUNG V BNH 1. KHI NIM V BNH K t thi nguyn thu ti nay, qua bao ngn nm, khi nim v bnh l bt bin. iu khng ng m n thay i theo thi gian. Ni chung, s thay i ny ph thuc ch yu vo hai yu t: - Trnh vn minh ca x hi ng thi. - Th gii quan (bao gm c trit hc) ca mi thi i. Trong mt x hi, c th ng thi xut hin nhiu khi nim v bnh, k c nhng khi nim i lp nhau. l iu bnh thng ni ln nhng quan im hc thut khc nhau c th cng tn ti trong khi ch i s ng ng. Tuy nhin, trong lch s c nhng trng hp quan im chnh thng tm cch n p cc quan im khc. Mt quan nim v bnh bao gi cng chi phi cht ch cc nguyn tc cha bnh, phng bnh. Do vy n c vai tr rt ln trong thc tin. 1.1. Mt s khi nim trong lch s 1.1.1 Thi nguyn thu Ngi nguyn thu khi bit t duy cho rng bnh l s trng pht ca cc ng siu linh i vi con ngi v trn th. y c s ln ln gia bn cht ca bnh vi nguyn

nhn gy ra bnh (tr li cu hi "bnh l g" cng ging cu hi "bnh do u"). Khng th i hi mt quan nim tch cc hn khi trnh con ngi cn qu thp km, vi th gii quan coi bt c vt g v hin tng no cng c cc lc lng siu linh can thip vo. ng ch l quan nim ny bc sang th k 21 vn cn tn ti nhng b tc lc hu hoc mt s b phn dn c trong cc x hi vn minh. Vi quan nim nh vy th ngi xa cha bnh ch yu bng dng l vt cu xin, c th cu xin trc tip, hoc thng qua nhng ngi lm ngh m tn d oan. Bao gi cng vy, gi tr ca vt l lun lun nh hn gi tr ca iu cu xin. Tuy nhin, trn thc t ngi nguyn thu bt u bit dng thuc, khng phi ch ph mc s phn cho thn linh. 1.1.2. Thi cc nn vn minh c i Trc cng nguyn nhiu ngn nm, mt s vng trn th gii t trnh vn minh rt cao so vi mt bng chung. V d: Trung Quc, Hy Lp, La M, Ai Cp hay n . Trong x hi hi xut hin tn gio, tn ngng, vn hc ngh thut, khoa hc (gm c y hc v trit hc). Nn y hc lc mt s ni t c nhng thnh tu ln v y l cng nh v phng php cha bnh v a nhng quan nim v bnh ca mnh. 7 1.1.2.1. Trung Quc c i Khong hai hay ba ngn nm trc cng nguyn, y hc chnh thng Trung Quc chu nh hng ln ca trit hc ng thi cho rng vn vt c cu to t nm nguyn t (Ng hnh: Kali, Mc, Thu, Ho, Th) tn ti di hai mt i lp (m v dng) trong quan h h tr hoc t ch ln nhau (tng sinh hoc tng khc). Cc nh y hc c i Trung Quc cho rng bnh l s mt cn bng m dng v s ri lon quan h tng sinh tng khc ca Ng hnh trong c th. T nguyn tc cha bnh l iu chnh li, kch thch mt yu (b), ch t mt mnh (t). Trong thi k ny quan nim v bnh y l duy vt, cc th lc siu linh bt u b loi tr khi vai tr gy bnh. C nhin, y mi ch l trnh duy vt ht sc th s (cho rng vt cht ch gm nm nguyn t) v trong nhiu ngn nm, quan nim ny t ra bt bin, khng h vn dng c cc thnh tu v i ca cc ngnh khoa hc t nhin khc vo y hc. Y l Trung Quc c i kh phong ph v cht ch, thc s c vai tr hng dn cho thc hnh, ng thi c th t ho v tnh bin chng su sc. Tuy nhin, trnh bin chng y ch l rt chung chung, tru tng. Do vy, y l ch dng li mc l thuyt (do quan st v suy lun m c) cha th gi l t mc l lun (dng thc nghim kim tra v chng minh m c). Y hc v y l Trung Quc c i c nhng ng gp rt ln cho chn on v cha bnh. nh hng ca n lan c sang phng Ty, xm nhp c vo y l ca mt nn y hc c chu u. Ngi ta cho rng chnh l thuyt v "bn nguyn t" ca Pythagore v "bn cht dch" ca Hippocrat cng chu nh hng r rt ca y l Trung Quc c i. Tri qua hng ngn nm tn ti v pht trin, nn y hc ny c nhng ng gp ht sc to ln, vi v s bi thuc phong ph v cng hiu. Tuy nhin, cho n khi ch ngha t bn chu u bnh trng sang phng ng tm thuc a ng thi mang theo y hc hin i sang chu - n ch vn dng mc y hc c truyn m cha h c yu t hin i no. Nguyn nhn do ch phong kin Trung Quc tn ti qu lu, vi quan nim "cht m khng ton vn c th" l iu ht sc au kh, nhc nh cho c ngi cht

v thn nhn h. Do vy, mn gii phu khng th ra i. Cc nh y hc ch c th dng tng tng v suy lun m t cu trc c th. Tip sau l mt chui di nhng suy lun v suy din, mc d t nhiu c i chiu vi quan st thc tin nhng khng sao trnh khi sai lm (v khng c thc nghim chng minh). Tuy nhin, y vn ch l nhng quan st trc tip bng cc gic quan (d rt t m) m khng c trang thit b h tr nn ch c th dng li hin tng v sau li tip tc dng suy lun mong hiu c bn cht. 8 1.1.2.2. Thi vn minh Hy Lp v La M c i Mun hn Trung Quc hng ngn nm. Y hc c i ca nhiu nc chu u cng chu nh hng kh r ca Trung Quc, ni bt nht l Hy Lp -La M c i. Gm hai trng phi ln: - Trng phi Pythagore (600 nm trc cng nguyn): da vo trit hc ng thi cho rng vn vt do bn nguyn t to thnh vi bn tnh cht khc nhau: th (kh), kh (m), ha (nng), thu (lnh). Trong c th, nu bn yu t ph hp v t l, tnh cht v s cn bng s to ra sc kho; nu ngc li, s sinh bnh. Cch cha bnh cng l iu chnh li, b sung ci thiu v yu, loi b ci mnh v tha. - Trng phi Hippocrat (500 nm trc cng nguyn): khng ch thun tu tip thu v vn dng trit hc nh trng phi Pythagore m tin b v c th hn, quan st trc tip trn c th sng. Hippocrat cho rng c th c bn dch, tn ti theo t l ring, c quan h cn bng vi nhau to ra sc kho, l: + Mu : do tim sn xut, mang tnh nng; ng nhn xt rng khi c th lm vo hon cnh nng (st) th tim p nhanh v mt, da u bng. l do tim tng cng sn xut mu . + Dch nhy: khng mu, do no sn xut, th hin tnh lnh; xut pht t nhn xt khi c th b lnh th dch mi chy ra rt nhiu, ngc li khi nim dch xut tit nhiu cng l lc c th nhim lnh. + Mu en: do lch sn xut, mang tnh m. + Mt vng: do gan sn xut, mang tnh kh. Bnh l s mt cn bng v t l v quan h gia bn dch . L thuyt ca Hippocrat c nh hng rt ln i vi y hc chu u thi c i. Bn thn Hippocrat l nh y hc c truyn v i, c cng lao tt ln; tch y hc khi nh hng ca tn gio, ch trng chn on bng pht hin triu chng khch quan, cao o c y hc. thi k ny quan nim v bnh kh duy vt v bin chng, tuy cn th thin. C th ni y l c im d t c khi l thuyt cn s si, dng li trnh chung chung v tru tng. Tuy nhin, nhng quan st trc tip ca Hippocrat li kh c th nh bn cht dch l c tht v cho php kim chng c. Nh vy, cc th h sau c iu kin kim tra, sa i v pht trin n, nht l khi phng php thc nghim c p dng vo y hc, a y hc c truyn tin ln hin i. Chnh v vy, Hippocrat c tha nhn l ng t ca y hc ni chung c y hc c truyn v hin i. 1.1.2.3. Cc nn vn minh khc - C Ai Cp: Da vo thuyt Pneuma (sinh kh) cho rng kh em li sinh lc cho c th. C th phi thng xuyn h hp a sinh kh vo. Bnh l do ht phi kh xu khng trong sch. T , cc nh y hc ra nhng nguyn tc cha bnh. 9 - C n : Y hc chnh thng chu nh hng su sc ca trit hc o Pht cho

rng cuc sng l mt vng lun hi (gm nhiu kip), mi kip tri qua bn giai on: sinh, lo, bnh, t. Nh vy, bnh l iu khng th trnh khi. Tuy nhin, cc nh y hc c i n vn sng to c rt nhiu phng thuc cng hiu cha bnh. o Pht cn cho rng con ngi c linh hn vnh vin tn ti, nu n cn ng tr trong th xc tn ti tm thi l sng, e do thot khi xc l bnh, thot hn khi th xc l cht. 1.1.3. Thi k Trung c Chu u thi k Trung c (th k 4-12) c coi l "m di" v din ra sut 8 th k di s thng tr tn bo v h khc ca nh th, tn gio v ch phong kin. Nguyn nhn do s cung tn vo nhng l thuyt mang tnh tn gio khin cc gio s da vo cng quyn sn sng n p khc lit cc kin i lp. Tuy nhin, nguyn nhn su xa hn l tng lp gio s v phong kin mun bo v lu i c quyn thng tr ca h. - Cc quan nim tin b b n p nu tri vi nhng tn iu trong kinh thnh, khoa hc lm vo tnh trng tr tr v tht li. Cc nh khoa hc tin b b khng b. - Quan nim chnh thng v bnh t ra rt m mui, khng coi trng cha bng thuc, thay bng cu xin, y l phi tun theo cc gio l ca nh th, mi v thnh trn gi mt b phn trong c th, mt s gio s cm c sch thuc... Nhng nh y hc c quan im tin b b ngc i. Tuy vy, cui thi Trung c vn lc c c vi quan nim duy vt nhng rt s si, PHracelsus (1493-1541) cho rng lu hunh c vai tr biu hin sc mnh ca linh hn, tr tu, cn thu ngn v mui c vai tr trong duy tr sc mnh th cht. Tuy vy, cc quan im ny khng c coi l chnh thng nn t nh hng trong gii y hc. 1.1.4. Thi k Phc hng Th k 16-17, x hi thot khi thn quyn, vn hc ngh thut v khoa hc phc hng li n r vi nhiu tn tui nh Newton, Descarte, Toricelli, Vesali, Harvey... Gii phu hc (Vesali, 1414-1564) v Sinh l hc (Harvey, 1578-1657) ra i t nn mng vng chc y hc t c truyn tin vo thi k hin i. Nhiu thuyt tin b v y hc lin tip xut hin. Tnh duy vt tuy cn th s, tnh bin chng vn cn my mc nhng so vi thi k y hc c truyn th c nhng bc tin nhy vt v cht. thi k ny c c im l: - Mi thuyt u c th hn trc, gim mc tru tng, khin c th dng thc nghim kim tra d dng tha nhn hoc bc b; ng thi c tc dng gim bt tnh ngh thut tng thm tnh khoa hc v tnh chnh xc trong hnh ngh ca ngi thy thuc. 10 - Cc thuyt u c vn dng cc thnh tu mi nht ca cc khoa hc khc nh co hc, l hc, ha hc, sinh hc, sinh l, gii phu. V d: + Thuyt c hc (Descarte): Coi c th nh mt c my, v tim nh ci my bm, mch mu l cc ng dn; cc xng nh nhng n by v h c nh cc lc. Bnh c v nh trc trc ca my mc... + Thuyt ha hc (Sylvius, 1614-1672): coi bnh tt l do s thay i t l cc ha cht trong c th, hoc s ri lon ca cc phn ng ha hc. + Thuyt lc sng (Stalil, 1660-1734): Cc nh sinh hc hi cho rng cc sinh vt c nhng hot ng sng v khng b thi ra l nh trong chng c ci gi l lc sng. Lc sng cng chi phi sc kho v bnh tt ca c th bng lng v cht ca

n. 1.1.5. Thi k th k 18 -19 y l thi k pht trin ca y hc hin i vi s vng mnh ca hai mn Gii phu hc v Sinh l hc. Nhiu mn y hc v sinh hc ra i. cc nc phng Ty, y hc c truyn hon ton tin sang thi y hc hin i. Phng php thc nghim t vt l hc c ng dng mt cch ph bin v c h thng vo y hc mang li rt nhiu thnh tu. Rt nhiu quan im v bnh ra i, vi c im ni bt da trn nhng kt qu c thc nghim kim tra v khng nh. Mt s quan nim ch yu v bnh trong thi k ny l: - Thuyt bnh l t bo: Wirchow l ngi sng lp mn Gii phu bnh cho rng bnh l do cc t bo b tn thng, hoc cc t bo tuy lnh mnh nhng thay i v s lng, v tr v thi im xut hin. - Thuyt ri lon hng nh ni mi: Claud Benard - nh Sinh l hc thin ti, ngi sng lp mn y hc thc nghim, tin thn ca mn Sinh l bnh - a thc nghim vo y hc mt cch h thng v sng to, ra khi nim "hng nh ni mi" cho rng bnh xut hin khi c ri lon cn bng ny trong c th. - Mun hn, sang th k 19-20, Frend (1856-1939) v mn cho rng bnh l do ri lon v mt cn bng gia thc, tim thc, bn nng. Mn Pp-lp lm dng qu mc cc cng trnh ca ng th cho rng bnh l kt qu ca s ri lon hot ng phn x ca thn kinh cao cp. Cc khi nim ny c ng gp nht nh trong mt phm vi no , ng thi cng biu hin nhng thin lch hiu bit v bnh. 1.1.6. Thi k hin i (Th k 20) Th k ny l thi k ca in t, ca cc cht cao phn t v cng l thi k ca sinh hc. Mt s ngnh sinh hc pht trin mnh nh: di truyn hc, min dch hc, sinh hc phn t... c nh hng ln ti y hc, do cng c nhiu khi nim khc nhau v bnh. 11 Ring Nga, tip thu cc cng trnh ca cc nh khoa hc nh Sechenov, Botkin, Pp-lp ra hc thuyt thn kinh ca bnh. Theo thuyt ny ni mi v ngoi cnh l mt khi thng nht, trong hot ng ca thn kinh cao cp ng vai tr quyt nh i vi kh nng thch ng ca c th (tc ni mi) vi nhng thay i bn ngoi. S kt hp cht ch gia v no v nhng on di ca h thn kinh, gia h thng tn hiu th nht v th hai ca ngi, gia thn kinh v ni tit c tc ng iu ho chnh xc v kp thi mi hot ng ca c th, m bo mi tng quan chnh xc gia ni mi v ngoi cnh. Bnh tt l do ri lon hot ng phn x ca h thn kinh, ri lon tng quan gia cc khu vc khc nhau ca h thn kinh. Pp-lp ch r: "trong ngi bnh c hai qu trnh tn ti song song: qu trnh bo v sinh l v qu trnh hu hoi bnh l". Qua cc l lun trn cc nh khoa hc Nga nhn nhn vn bnh tt mt cch ton din hn. Tuy nhin vn cha gii thch mt cch hon ho khi nim v bnh. Trong thi k ny, ngnh ha cht, nht l sinh ha pht trin mnh m, ngi ta nhn thy tnh cht tng i n nh ca cc thnh phn ha hc trong c th. Da vo Hens Selye a ra kin "Bnh l s ri lon cc kh nng thch nghi". Nghin cu cc tc ng mnh ca ngoi cnh (stress) th Selye cho rng bao gi c th cng p li bng nhng thay i ca hot ng ni tit v thn kinh. Theo Selye s mt cn bng v hip ng gia h no v thng thn th sinh ra bnh gi l bnh thch nghi.

Theo tin ha lun khoa hc th mi sinh vt u bt ngun t mt n bo, sau phc tp dn thnh c quan, t chc khc nhau, c cc hot ng ring nhng nhm mc ch chung l duy tr s sng. Do , s ngn cch gia cc b phn (t bo, c quan), gia c th trong cng ng, gia c th vi thin nhin ch cc tnh cht tng i, m v thc cht c s lin quan trao i mt thit qua li vi nhau, nh hng ln nhau. Gia ngoi cnh v c th c s thng nht v c s mu thun, ngoi cnh th lun lun thay i v c th nh kh nng thch nghi ca mnh m duy tr hng nh ni mi mt cch tng i, duy tr s sng. 1.2. Quan nim v bnh hin nay 1.2.1. Hiu v bnh qua quan nim sc kho - T chc Y t th gii (WHO - 1946) a ra nh ngha: "Sc kho l mt tnh trng thoi mi ton din v th cht, tinh thn v x hi, ch khng ch n thun l khng c bnh hay tt". y l nh ngha mang tnh mc tiu x hi, phn u, c chp nhn rng ri. - Tuy nhin di gc y hc, cn c nhng nh ngha ph hp v cht ch hn. Cc nh y hc cho rng: "Sc kho l tnh trng lnh ln ca c th v cu trc, chc nng, cng nh kh nng iu ho gi cn bng ni mi, ph hp v thch nghi vi s thay i ca hon cnh". 1.2.2. Nhng yu t nh ngha v bnh 12 a s cc tc gi u a vo khi nim bnh nhng yu t sau: - S tn thng, lch lc, ri lon trong cu trc v chc nng (t mc phn t, t bo, m, c quan n mc ton c th). , - Do nhng nguyn nhn c th, c hi; tm ra hay cha tm ra. - C th __________c qu trut phn ng nhm loi tr cc tc nhn gy bnh, lp li cn bng, sa cha tn thng. Trong c th b bnh vn c s duy tr cn bng no , mc d n lch ra khi gii hn sinh l. Hu qu ca bnh tu thuc vo tng quan gia qu trnh ri lon, tn thng v qu trnh phc hi, sa cha. Bnh lm gim kh nng thch nghi vi ngoi cnh. - Vi ngi, c tc gi ngh thm: bnh lm gim kh nng lao ng v kh nng ho nhp x hi. 1.2.3. Mt s nh ngha v bnh "Bnh l tnh trng tn thng hoc ri lon v cu trc v chc nng, dn ti mt cn bng ni mi v gim kh nng thch nghi vi ngoi cnh". - "Bnh l s ri lon cc hot ng sng ca c th v mi tng quan vi ngoi cnh, dn n gim kh nng lao ng". "Bnh l s thay i v lng v cht cc hot ng sng ca c th do tn thng cu trc v ri lon chc nng, gy ra do tc hi t mi trng hoc t bn trong c th". - "Bnh l s ri lon i sng bnh thng ca c th sinh vt, do tc ng ca cc yu t gy bnh khc nhau, gy ra mt qu trnh u tranh phc tp gia hin tng tn thng bnh l v hin tng phng v sinh l, lm hn ch kh nng thch nghi ca c th i vi ngoi cnh, lm cho kh nng sn xut v gi tr kinh t b gim st". - "Bnh l mt iu kin m mt c th ch ra s sai khc v gii phu, ha hc, sinh l so vi bnh thng". - nh ngha "th no l mt bnh" hin nay ang c s dng ph bin l:

"Bnh l bt k s sai lch hoc tn thng no v cu trc v chc nng ca bt k b phn, c quan, h thng no ca c th biu hin bng cc triu chng c trng gip cho thy thuc c th chn on xc nh v chn on phn bit, mc d nhiu khi ta cha r v nguyn nhn, v bnh hc v tin lng" (T in y hc Dorlands, 2000). 2. I CNG V BNH NGUYN HC 2.1. nh ngha Bnh nguyn hc (Etiology) hay nguyn nhn bnh hc l mn hc nghin cu v 13 nguyn nhn gy bnh, bn cht ca chng, c ch m chng tc ng, ng thi nghin cu cc iu kin thun li hay khng thun li nguyn nhn trn pht huy tc dng. Vic nghin cu nguyn nhn gy bnh c ngha rt to ln trong l lun cng nh trong thc hnh. V l lun n biu hin mt lp trng r rt; v thc hnh n gip cho vic phng tr c hiu qu. Pp-lp ni: "Vn pht hin ra nguyn nhn gy bnh l mt vn c bn ca y hc v ch khi no bit r nhng nguyn nhn gy ra bnh th mi tin hnh iu tr c chnh xc, hn na mi ngn chn chng t nhp vo c th v iu ny l quan trng bc nht". 2.2. Mt s quan nim sai lm v bnh nguyn hc c c nhng quan im v khi nim khoa hc ng n nh hin nay, bnh nguyn hc tri qua mt qu trnh nghin cu lu di v u tranh gay gt gia cc hc thuyt khc nhau. Trong c mt s hc thuyt sai lm v nguyn nhn bnh hc nh: - Thuyt "nguyn nhn n thun" (Pure Etiology) cho rng vi khun l nguyn nhn ca mi bnh, h c vi khun l c bnh (tc l mi bnh u do mt nguyn nhn v ch khi no c nguyn nhn th mi c bnh). Vi thi cc oan, qu nhn mnh n vai tr ca mt nguyn nhn gy ra bnh l vi khun, thuyt ny b qua vai tr v nh hng ca nhng iu kin khc thun li cho s pht sinh ca bnh, cng khng ch n c ch bo v ca c th chng li s t nhp ca cc yu t gy bnh v n cng khng xt n cc nh hng khc trong bnh nguyn hc. Thc t cho thy rng, trong nhiu bnh khng pht hin thy vi khun nh bnh cao huyt p, cc bnh o tc ng ca cc yu t l, ha hc gy nn v ngc li, trong nhiu trng hp c vi khun nhng li khng thy bnh xut hin, v d: c ti 80-90% g mang vi khun PHsteurella trong ng h hp trn m khng gy bnh t huyt trng hoc c ti gn 100% vi khun E, cn sng trong rut gi ca ng vt v ngi m khng gy bnh. Mt quan nim sai lm, phin din v bnh nguyn hc nh trn, ch ch n mt nguyn nhn gy bnh, tt nhin cng s dn n sai lm trong cng tc phng bnh v iu tr bnh. Nh ta bit vic chng li yu t gy bnh, nht l vi khun mt cch tch cc cng mi ch l mt mt trong cng tc phng bnh v iu tr. Cn c nhng mt khc cng khng km phn quan trng l to ra nhng iu kin, nhng hon cnh yu t gy bnh khng pht huy c tc dng nh tng cng sc khng ca c th, v.v Thuyt "iu kin n thun" (Pure Condition) cho rng bnh tt l do kt qu tc ng tng hp ca mt s iu kin v cc iu kin c th gy bnh m khng cn c nguyn nhn c hiu. Quan nim ny l hon ton sai lm, bi v tng iu kin tch ring ra, cng nh nhiu iu kin kt hp li khng th quyt nh c s pht sinh ra bnh v tnh c hiu ca bnh, v d: nu khng c vi

14 khun lao th khng c bnh lao. Cc iu kin ch c tc dng to nn c s d dng cho bnh pht sinh khi c nguyn nhn gy bnh tc ng. Hc thuyt ny mang tnh cht tiu cc: cng mt lc a ra nhiu iu kin i hi phi tho mn th mi c th gii quyt c vn bnh tt. V vy n gy tr ngi cho cng tc phng bnh v tr bnh. N khng phn bit nguyn nhn v iu kin v cng khng ch r c vai tr ca mi yu t trong qu trnh gy bnh. Thuyt "th tng" (Constitution) cho rng nguyn nhn gy bnh khng phi t bn ngoi ti m chnh l do c im ca c th, do th tng ca con vt m ra. y l quan nim ca thuyt di truyn my mc, n khng k n cc yu t ngoi cnh tc ng n qu trnh pht trin v di truyn ca sinh vt. Nh vy n chng li vic v sinh phng dch, bo v sc kho cho gia sc ngn nga bnh tt. 2.3. Quan nim khoa hc v bnh nguyn hc Mt s quan nim ng n v bnh nguyn hc l phi da vo phng php duy vt bin chng nu ln c mi quan h ng n gia nguyn nhn v iu kin gy bnh. 2.3.1. Mi quan h gia nguyn nhn v iu kin gy bnh - Nguyn nhn c vai tr quyt nh v iu kin th pht huy vai tr tc dng ca nguyn nhn. Nguyn nhn gy bnh l yu t c hi, khi tc ng ln c th s quyt nh bnh pht sinh v cc c im ca bnh, v d: Bn bnh ca ln (l bnh ph thng hn, t huyt trng, ng du, dch t) do bn nguyn nhn khc nhau gy ra v pht sinh ra bnh c biu hin ring. Nhng yu t gy bnh khi vo c th phi t cng nht nh (c lc, liu lng cao...). c im ca bnh chnh l do nguyn nhn quyt nh v chnh da vo nhng c im ca bnh m ta c th khm ph ra nguyn nhn t m xc nh phng php cn thit iu tr. Song nguyn nhn gy bnh ch c th pht huy tc dng trong nhng iu kin c th nht nh, v d: Bnh t huyt trng g pht trin di tc dng ca vi khun PHsteurella nhng phi c th yu, dinh dng km v c bit l khi thi tit thay i t ngt. Ngc li, khi c y cc iu kin thun li nhng khng c nguyn nhn th bnh khng th pht sinh v xy ra c, n ch pht sinh ra bnh khc nh suy dinh dng, ci xng. Nguyn nhn v nhng iu kin nht nh gy nn mt bnh c gi chng l nhng yu t bnh nguyn. - Trong nhng iu kin nht nh, nguyn nhn c th tr thnh iu kin, ngha l trong nhng hon cnh no , mt s yu t c th l nguyn nhn nhng trong hon cnh khc n c th tr thnh iu kin. V d: nui dng km l nguyn nhn ca suy dinh dng, thiu vitamin l nguyn nhn ca bnh thiu vitamin, song c th li l iu kin cho cc bnh nhim khun pht trin. Hoc bnh ghp t huyt trngdch t ln, dch t-t huyt trng ln. 15 V d: Khi khu phn n thiu protein s gy nn ph do protein trong huyt thanh gim m p lc keo da vo nng protein huyt thanh. Nu protein huyt thanh gim lm cho p lc keo trong mu gim t lm cho nc b y t ng mch ra ngoi gian bo gy ra hin tng ph (bnh thn), hoc khi thiu vitamin B1 th cng gy ra ph. 2.3.2. Quy lut nhn qu trong bnh nguyn hc - Mi bnh (tc l hu qu) u c nguyn nhn nht nh gy ra v nguyn nhn bao gi cng c trc hu qu. Nguyn nhn gy bnh d t ngoi vo hay t trong ra

u tc ng ln c th sinh ra hu qu l bnh. Bt c mt bnh no cng u c nguyn nhn nht nh gy nn. Mc d hin nay rt nhiu bnh cha tm c nguyn nhn nhng ai cng tin rng bt c bnh no cng phi c nguyn nhn. - C nguyn nhn nhng khng nht thit pht sinh ra hu qu (tc bnh) nu khng c iu kin thun li. Nh trn ta ni v mi quan h gia nguyn nhn v iu kin, trong iu kin pht huy tc dng quyt nh ca nguyn nhn. Song cng cn phi hiu r rng, trong sinh hc ni chung cng nh trong y hc ni ring, v tnh cht phc tp ca hin tng sng, phn ng ca sinh vt cn ph thuc vo nhiu yu t m trnh khoa hc, k thut hin nay cn cha pht hin v kim sot c. Cho nn p ng ca sinh vt i vi yu t gy bnh c th thay i tu theo iu kin bn ngoi cng nh bn trong. iu kin bn ngoi th mun hnh mun v, cn iu kin bn trong th v cng phc tp cho nn tnh phn ng thng thay i theo tng c th. Do vy, cng mt nguyn nhn trong nhng iu kin nht nh th tc ng gy nn bnh nhng nhng iu kin khc th li khng gy ra bnh. Cng mt nguyn nhn, c th c nhng hu qu khc nhau tu theo iu kin, v d: bnh cm ngi, kh iu kin sng nh nhau nhng tu thuc vo tng c th m c ngi b nng, c ngi b nh, c ngi khng mc bnh. Cng mt nguyn nhn tu ni tc ng v tu theo p ng ca c th m hu qu (l bnh) c th khc nhau, v d: T cu khun c th gy nn p xe khi vo da, gy nn a lng khi vo rut v gy nhim khun huyt khi vo mu. - Mt hu qu (triu chng bnh) c th do nhiu nguyn nhn khc nhau gy ra nh vim, st l nhng qu trnh bnh l in hnh, trong cc triu chng rt d dng c xc nh song li do rt nhiu nguyn nhn gy nn: cm lnh cng dn n st; chn thng cng gy nn st. Chnh y l kh khn thng gp khi i t nhng triu chng ti xc nh c bnh v nguyn nhn gy bnh, i hi phi c phng php suy lun ng n v logic phn bit gia hin tng v bn cht. Nh vy mt quan nim khoa hc v bnh nguyn hc phi c tnh cht ton din, nhn nhn c vai tr ca nguyn nhn, iu kin cng nh th tng. Song mi mt yu t c tm quan trng v v tr nht nh trong qu trnh gy bnh. Ngn nga nguyn 16 nhn, hn ch tc dng ca iu kin gy bnh, tng cng hot ng tt ca th tng, l nhng mt hot ng tch cc, l iu kin quan trng trong cng tc iu tr v phng bnh. iu tr khng ch tm ra c nguyn nhn m cn phi thy c c nhng iu kin trong bnh cnh din ra. 2.4. Phn loi cc yu t bnh nguyn 2.4.1. Yu t bnh nguyn bn ngoi 2.4.1.1. Yu t c hc Ch yu l chn thng cho cc m bo v cc c quan, h thng ca c th. Hu qu ti ch b tn thng, mt mu, nhim khun th pht...v hu qu ton thn l c th b sc. 2.4.1.2. Yu t l hc - Nhit : + Nu nhit qu 500C c th gy bin tnh cc protein v men trong t bo, nh hng xu ti chc nng hoc gy cht t bo. + Nu nhit qu cao: gy vim, bng hoc chy ti ch tip xc; + Nu nhit cao v tc ng ln ton thn: gy nhim nng;

+ Nhit qu lnh gy t cng, hoi t ti ch tip xc hoc gy nhim lnh khi tc ng ln ton thn. - Tia phng x: Gy hu hoi cc men t bo, tc hi tng t nhit trn 500C nhng ch yu l tc hi ln ADN, nht l khi t bo ang phn chia (nh t bo non tu xng). C ch tc ng: tia.x vi nng lng mang theo chng to ra cc sn phm ton ha v cc gc t do, gy ri lon chuyn ha cho t bo, k c gy cht t bo. - Dng in: tu thuc din tip xc rng hay hp v in tr thp hay cao. + Tu thuc vo in p: in p cng cao th cng nguy him, nht l t 220V tr ln. + Tu thuc vo dng in: dng mt chiu tc dng rt nhanh; dng xoay chiu: tn s 25-50 rt nguy him. + C th gy bnh ti ch (bng) hay ton thn. + Tu thuc c quan (nu dng in qua tim, no gy nguy him; qua c gy co cng). + Tu thuc vo kh nng in ly ca cc dch trong c th. 2.4.1.3. Yu t ha hc v c cht Tu bn cht ha hc v liu lng ca ha cht m c th gy bnh ti ch (ni 17 tip xc) hay ton thn (khi xm nhp vo c th) vi cc c ch rt khc nhau. - Hai cch tc ng ch yu l gy tn thng, ph hu (hoi t, tan huyt...), hoc gy ri lon chuyn ha, suy gim hay kch thch qu mc chc nng c quan (ng c, suy thn, suy gan, hn m, co git...). Cc axit mnh, kim mnh v mt s cht khc c th gy bng, chy, hoi t da v nim mc khi tip xc. - Nhiu cht c tc dng hu men trong t bo, hoc gy ng c ton thn do lm ri lon chuyn ha (vi cc c quan ch khc nhau nht l cc c quan tch lu v o thi chng nh gan, thn) vi mc , hu qu khc nhau. - Cc cht ha hc bao gm: + Cht v c (ch, hp cht thu ngn, arsenic...); + Cc cht hu c (benzen, phenylhydrazin, mt s dc cht nu qu liu...); + Mt s sn phm ca ng vt hay thc vt (nc rn, nc b cp, cht c trong mt c trm, gan cc, trong mt s nm c, l ngn, l han...). 2.4.1.4. Yu t sinh hc Bao gm cc loi sinh vt, vi khun, vi rt, k sinh trng, cn trng. Tu theo nguyn nhn gy bnh m ngi ta xp vo hai loi bnh l: - Bnh truyn nhim - Bnh k sinh trng 2.4.2. Yu t bnh nguyn bn trong 2.4.2.1. Yu t di truyn l nhng bin i bnh l thng qua c ch di truyn t th h trc sang th h sau qua t bo sinh dc mang n bnh. Qua nghin cu ngi ta thy, mt s bnh pht sinh l do thiu mt s tin ch huy tng hp nn cc loi men, m thiu cc men y s pht sinh ra bnh. V d: Bnh phenylxeton niu l do thiu men pHrahyroxylaza nn phenylalanin khng chuyn thnh tyrxin c m phn hu thnh phenylxeton v c o thi ra ngoi qua nc tiu. Yu t di truyn c th cng l iu kin cho bnh pht sinh. mt s con gi sc ci y khng biu hin ra bnh nhng mang gen ln trong

nhim sc th. V d trn ln mang bnh c k hiu l x+, en khng bnh k hiu l x, con ci c k. hiu l Xx+, con c khng c bnh c k hiu l XY. Ta c s sau: 18 Nh vy 1/2 s con c (x+Y) sinh ra mc bnh 1/2 s con ci (x+X) sinh ra mang gen bnh Nu c con c v ci mang n bnh th khi chng giao phi ta c s sau: Nh vy ta thy: 1/2 s con c sinh ra mc bnh (x+Y) 112 s con ci sinh ra mc bnh (x+x+) 1/2 s con ci sinh ra mang n bnh (x+X) Tm li ch c 1/4 s con sinh ra l kho mnh v 3/4 s con khc l mc bnh hoc mang n bnh. Lu : C mt s trng hp trc khng b bnh nhng do b t bin trn sau khi b cht phng x hoc b nhim c ha hc tr thnh ngi mang n bnh v di truyn c. 2.4.2.2. Yu t th tng Th tng c th nh ngha nh l tng hp cc c im chc nng v hnh thi ca c th. Nhng c im ny kh bn vng, c hnh thnh trn c s tnh di truyn v quyt nh nhng.phn ng ca c th i vi tc nhn bn ngoi trong qu trnh sng. Nh vy th tng c tnh cht rt phc tp trong yu t di truyn ng vai tr ch cht, quyt nh. Trc mt yu t gy bnh, nhng c th c th tng khc nhau s c p ng khc nhau hay ni cch khc th tng l c s vt cht ca tnh phn ng v chu nh hng ca mt s yu t nht nh nh chng loi, gii tnh, tui tc, hot ng ca h thn kinh, ni tit v mi trng m trong con vt sinh sng. Cho nn thay i mi trng sng c th lm thay i phn ng tnh ca c th v do lm thay i phn no th tng. V d: Bnh chm th tng ging nh bnh Eczema do c th thch hp vi mt loi nm no , cho nn khng th cha c nhng khng ly lan sang ngi khc, m n c di truyn t th h ny qua th h khc. 3. I CNG V BNH SINH HC 3.1. nh ngha 19 Bnh sinh hc hay sinh bnh hc (Pathogenesis) l mn khoa hc nghin cu nhng quy lut c bn ca s pht sinh, pht trin, din bin v kt thc ca mt qu trnh bnh l hay c ch sinh bnh. i vi mi mt bnh nh ta bit u c mt nguyn nhn nht nh tc ng v sau l s pht sinh din bin ca bnh. V vy nm c c ch sinh bnh l yu cu c bn trong cng tc phng tr bnh, trn c s c th ngn chn sm c nhng din bin xu ca bnh, hn ch c tc hi, ng thi xc nh nhng bin php tch cc bo v n vt nui. 3.2. nh hng ca bnh nguyn ti qu trnh bnh sinh Cng mt yu t bnh nguyn nhng bnh sinh c th thay i tu theo cng , liu lng, thi gian tc dng v v tr tc dng ca bnh nguyn. 3.2.1. nh hng ca cng v u lng bnh nguyn C rt nhiu bng chng v v d trong thc tin ni ln hai yu t ny ca bnh nguyn nh hng ln ti qu trnh bnh sinh. Cng tc ng vo mt v tr trn c th nhng cng dng in hoc cc tc nhn vt l khc nh nhit , tia x, nh sng, lc c hc... mnh hay yu s lm

bnh din ra rt khc nhau. - Cng mt cht c, cng mt ng xm nhp nhng liu lng khc nhau (ln hay nh) s gy ra nhng bnh c din bin khc nhau. - Cng mt loi vi khun, nu c lc hay s lng khc nhau cng lm bnh sinh din ra khng ging nhau. Cc tc nhn ha hc v sinh hc khc cng c nh hng tng t. - Nhng yu t vn khng gy bnh li c th gy bnh nu cng v s lng t mt ngng no . m thanh c cng cao, hoc khng kh c p lc qu ngng u tr thnh nhng yu t bnh nguyn rt hiu qu. 3.2.2. Thi gian tc dng ca bnh nguyn Nhng yu t bnh nguyn c cng cao hay liu lng ln thng ch cn thi gian ngn cng lm bnh pht sinh. Nu cng thp hn hoc liu lng nh hn th thng cn thi gian tc ng di hn. Nhng iu ng lu l din bin ca bnh cng thng thay i. V d: khi n lc b mc trong thi gian di c th dn ti mc bnh ung th; ting n d cng khng cao nhng nu c tc ng lin tc ngy m ln c quan thnh gic s gy bnh v din bin ca bnh khc hn trng hp c th chu mt m thanh cng qu cao (ting n). Tng t nh vy, tc dng lp i lp li nhiu ln ca mt yu t bnh nguyn d cha t ngng cng c th sinh bnh (ln, mt ng). 20 3.2.3. V tr tc dng ca bnh nguyn Mi c quan ca c th phn ng khc nhau vi cng mt bnh nguyn. Mt khc, tm quan trng sinh hc ca mi c quan cng khng ging nhau. Do vy, v tr tc ng ca bnh nguyn trn c th nh hng rt r ti bnh sinh. Bnh cnh, din bin ca bnh lao rt khc nhau, tu theo l lao phi, lao xng, lao thn hay lao mng no tuy bnh nguyn l mt. - Bnh nguyn d cng mt cng v liu lng nhng gy c bnh hay khng, nng hay nh, cp tnh hay mn tnh cn tu thuc v tr tc ng. nh sng chi ch gy c bnh nu chiu vo vng mc m khng phi vo u khc. Chn thng vo u c bnh cnh khc hn vo c bp hay vo xng. Dng in chy qua tim hoc qua no gy hu qu khc hn qua cc chi. V d: Bnh lu ngi: khi cu khun lu tc dng ng sinh dc gy vim mn tnh, cn khi cu khun lu gic mc mt gy vim cp tnh. 3.2.4. ng ly lan ca nguyn nhn bnh trong c th ng ly lan thng ph thuc vo tnh cht ca nguyn nhn bnh v v tr sinh bnh. Thng thng bnh nguyn lan theo ba ng chnh: , - Lan theo t chc: t ni pht bnh lan rng ra vng ln cn tip gip. - Lan theo dch th: thng cc yu t bnh nguyn l c t, vi khun, vi rt lan theo dch lm ba, mu n ton thn. - Lan theo thn kinh: cc yu t bnh nguyn cn l nhng xung ng au. Cc loi vi rt nh vi rt bnh di, c t un vn lan theo thn kinh. Trong thc t khi bnh pht sinh th yu t bnh nguyn c th lan theo nhiu ng ch khng phi lan theo mt ng ring bit, v trong kt cu t chc ca c th sinh vt ni no cng c mt cc h thng mch qun, thn kinh v mch lm ba. V vy, chng ta phi xem xt nhng bnh no lan theo ng no l ch yu bit v kp thi ngn chn.

3.3. Quan h gia cc b v ton thn trong qu trnh bnh sinh Theo thuyt thn kinh ca Pp-lp th c th l mt khi thng nht, cc c quan, m bo u c s lin h cht ch vi nhau v chu s iu tit chung ca thn kinh. Bt c mt c th no, hot ng no cng u chu s iu tit chung ca v no. V vy cc qu trnh bnh l d xy ra b phn cc b no cng ph thuc vo trng thi chung ca c th v ngc li thng qua cung phn x n nh hng ti ton thn. 3.3.1. Mi Lin h gia ton thn v cc b Ton thn kho mnh th sc khng ti ch cng s tt hn, do yu t gy bnh kh xm nhp hoc nu c vo c th cng nhanh chng b tiu dit hoc b o thi ra ngoi. Ngoi ra, ta thy tui c lin quan n sc khng. Tui trng 21 thnh c th kho mnh, vt thng mau lnh, phn ng nhanh, tui gi d mc bnh, phn ng km, vt thng lu lnh. 3.3.2. Mi lin h gia cc b v ton thn Bt k mt tn thng no (vim nhim) cc b cng u nh hng ti ton thn, u tin thy au, c th mt mi, cc cht c ti vim s ngm vo c th gy trng thi nhim c. Thnh phn ca mu thay i, nu bch cu a nhn trung tnh m tng ln th nht nh s b vim nhim mt ni no v gy st ton thn, ng thi lm thay i hot ng ca h thng nc tiu. Nh vy, khi cc b b tn thng th tt c cc c quan khc tng cng hot ng, c quan h hp thay i, c quan tiu ha gim, tit sa gim v tt c tp trung lc lng vo u tranh bo v c th. V vy c th ni bt k mt qu trnh bnh l no cng biu hin ti ch ca tnh trng bnh l ton thn. ngha: Nm c iu ny gip ta chm sc h l tt hn. 3.4. Vng bnh l Bnh din ra theo trnh t gm cc bc (gi l cc khu) ni tip nhau theo c ch phn x, khu trc l tin to iu kin cho khu sau hnh thnh v pht trin, cho ti khi bnh kt thc, nh s sau: Nhiu trng hp, mt khu no pha sau li tr thnh tin (nui dng) cho mt khu trc : t hnh thnh mt vng bnh l, vi c im l c kh nng t duy tr. Vng ny c th din bin cp tnh hoc ko di. Trong a s trng hp, vng bnh l lm cho qu trnh bnh sinh ngy cng nng hn, c th quan st d dng qua cc biu hin lm sng. Xem s di y: Thng th vng bnh l khng t mt i m cn c s can thip. Khi pht hin vng bnh l cn tm cch ct t nhiu khu, nht l khu chnh. Sau y l mt vi v d: - bnh ln ng du mn tnh, vi khun ln ng du gy vim ni tm mc, lot si van tim, do nh hng ti tun hon chung gy thiu oxy. T thiu oxy gy 22 ri lon chuyn ha ri tc ng tr li gy ph i tim dn n suy tim. Khi suy tim dn n thiu oxy v lp li thnh vng kn. - Khi t ngt mt i 20% lng mu, c th s huy ng mt lot bin php do h giao cm v h tim mch chi phi nhm b p mt phn khi lng mu, duy tr huyt p mc cn thit ti thiu, m bo c bn v lu lng tun hon v nhu cu oxy cho cc c quan quan trng nht. C th thch nghi dn, vng bnh l s khng hnh thnh trong thi gian ch i tu xng sn xut lng hng cu cn thit.

Nu mt ti 40% lng mu, cc bin php trn ch gip c th thch nghi c mt thi gian ngn v mu thun s pht sinh, h tim mch b qu ti chc nng li km c nui dng. C th thy huyt p tt dn, mch nhanh v yu dn, km theo tnh trng l m, da lnh, th trng xu dn i... ra khi tnh trng trn, h giao cm v tun hon li cng phi tng cng sut. Nh vy vng bnh l hnh thnh. ngha: Nm c s tin trin ca bnh, ta c th pht hin c khu chnh trong qu trnh sinh bnh v c tc ng cn thit ngn cn din bin xu ca vng bnh l. Qua y thy rng khu chm sc h l nhm ct c vng bnh l i l khu v cng quan trng. 3.5. Cc hin tng bnh l Trong mt c th b bnh ta c th nhn thy c nhiu hin tng bnh l khc nhau. Chng ta cn phi phn bit v xc nh nhng hin tng mt cch chnh xc. Cc hin tng l: 3.5.1. Phn ng bnh l Phn ng bnh l l phn ng ca t bo, ca t chc hay c quan i vi tc nhn gy bnh vi cng v cht lng vt ra ngoi gii hn bnh thng. V d: Khi b lnh, c th phn ng li bng cch co mch gim thi nhit, tng sn nhit trong c th, l phn ng sinh l. Nu co mch qu mc dn n thiu mu t dn n hoi t c. Nhng nu trung tm iu ho nhit b ri lon dn n hot ng qu mc ca c quan sinh nhit th sinh ra st, cn trong mt s bnh khc th biu hin ho, nn... ve thc cht l phn ng bo v sinh l nhng nu qu mc th s gy bnh. 23 3.5.2. Qu trnh bnh l Qu trnh bnh l l mt phc hp gm nhiu phn ng bnh l. V d: Trong qu trnh vim ngi ta thy c phn ng vn mch (co, gin mch), phn ng tng sinh t bo, phn ng ca thn kinh... Trong qu trnh st ngoi phn ng tng sn nhit cn c nhiu phn ng nhm gim thi nhit. Quan nim v qu trnh bnh l c tnh cht ng, n bao gm c qu trnh din bin ca bnh. 3.5.3. Trng thi bnh l L mt qu trnh bnh l bin chuyn chm, ko di thnh c tt. V d: Nhng ngi b lit, nhng ngi b vim khp sau khi khi li vt vim lm cho khp khng c ng c na hoc l vim v lm cho tuyn v teo i khng cho sa. 3.6. Cc giai on pht trin ca bnh Trong qu trnh pht trin ca bnh, c th c nhng bin i khc vi khi trng thi bnh thng. c trng cho nhng bin i l triu chng. Khi cc nguyn nhn gy bnh tc ng gy nhng bin i trong c th biu hin ra bn ngoi gi l triu chng. Hoc triu chng l nhng biu hin ca ng vt sng c quan st v miu t nh b n, a chy, bn chn, mt nc... v l kt qu ca nhng bin i t chc. Triu chng ca bnh th mun hnh, mun v, n bao gm nhiu bin i v hot ng, v chc nng, bin i v chuyn ha vt cht, bin i v thn nhit, v h hp, v tim mch n nhng thay i v thnh phn ca mu, nc tiu v c, s bin i v hnh thi ca c quan hay t chc. Triu chng thay i tu theo cc loi bnh khc nhau, tu theo tng giai on

pht trin ca bnh. Triu chng ph thuc vo c im c th vo la tui vo qu trnh pht trin ca bnh, ph thuc vo mi trng ngoi cnh bn ngoi. Nhn chung qu trnh pht trin ca bnh khng nhng din bin theo nhng quy lut nht nh m qu trnh ny cn c tnh cht giai on nht nh. Ngi ta thng chia ra bn thi k c bn trong qu trnh pht trin ca bnh. S phn chia ny c ngha quan trng trong nghin cu v gip cho vic phng tr bnh c chnh xc hn. Tuy nhin, vic nh ra ranh gii cc thi k mt cch r rng chnh xc l rt kh khn, cho nn s phn chia ra cc thi k cng ch l tng i trong qu trnh pht trin lin tc ca bnh. Da vo cc triu chng ngi ta phn chia ra thnh cc thi k pht trin ca bnh nh sau: 3.6.1. Thi k nung bnh (thi k bnh) Thi k nung bnh c bt u t khi nguyn nhn bnh xm nhp vo c th 24 hoc l nguyn nhn bnh bt u pht huy tc dng cho n khi m c th c nhng phn ng u tin. Lc ny nguyn nhn bnh cha s lng v c lc lm cho bnh pht trin, ng thi sc khng ca c th cn mnh, v th cha c nhng phn ng biu hin ca bnh. C th cng c th tiu dit nguyn nhn bnh, bnh khng pht hoc c th tin trin sang mt giai on khc. Thi k ny di hay ngn l ph thuc vo cc yu t sau y: - S lng, c lc v cng tc ng ca nguyn nhn bnh. - Trng thi c th v tnh mn cm ca c th i vi s tc ng ca nguyn nhn. - V tr mm bnh xm nhp. - iu kin ngoi cnh (c iu kin bn ngoi: thi tit kh hu, ch dinh dng, ch chm sc qun l...). Bng 1. Thi k bnh ca mt s bnh truyn nhim Bnh Thi gian bnh ngn nht Thi gian bnh di nht Thi gian bnh trung bnh Nhit thn Ung kh thn T huyt trng Sy thai truyn nhim Lao 2-4 gi 4-6 gi 4-6 gi 5-7 gi 6-7 ngy 14-15 ngy 14-15 ngy 6-8 ngy 1-2 thng

2-3 thng 2-3 ngy 2-3 ngy 1 -2 ngy 13-14 ngy 15-45 ngy ngha: Nm c thi k nung bnh, chng ta c bin php phng bnh bng cch l cch ly cc gia sc cha bit c l lch ca n v nui cch ly trong khong thi gian mt thng theo di tnh hnh bnh. 3.6.2. Thi k tin pht (thi k tin chng) Thi k ny bt u t khi c th c nhng phn ng u tin n khi bt u xut hin nhng triu chng ch yu. giai on ny, nguyn nhn bnh tc ng mnh lm cho c th thay i ton b cc phn ng, kh nng thch nghi ca con vt gim st, con vt c mt s biu hin du hiu ca bnh gi l tin chng. V d: Trng thi con vt thay i r, b n, hay nm, thm ch nm khng yn, nu o nhp tim c th nhanh, h hp tng, thn nhit cao, sung huyt nim mc... ngha: Cn c vo triu chng ny ta c bin php h l tt hn, chm sc tt hn v bc u chn on thm d, da vo dch t hc (ma v, vng, la tui...) bt u s chn sau ta iu tr thm d. Giai on ny v cng quan trng nn ta cn ch . 3.6.3. Thi k ton pht 25 Bt u t khi c th c nhng triu chng r rt, triu chng in hnh cho tng bnh cho n khi c th c nhng chuyn bin nht nh. thi k ny nguyn nhn bnh pht trin cc , sc khng ca con vt gim, c th c nhng c nng ri lon nghim trng. ngha: Da vo cc bnh bit c bin php i ph vi tng bnh mt theo truyn nhim hc x l, nu vi s lng ln phi bo ngay cho c quan chc nng cp trn c bin php phng nga. 3.6.4. Thi k kt thc Thi k ny di hay ngn ch yu ph thuc vo tng loi bnh v c bit l c s can thip ca Bc s Th y. C th bnh dn dn thuyn gim, cng cc triu chng gim dn ri mt ht hoc n c th tip tc theo vng bnh l v con vt c th cht khi b nng hn. Thi k kt thc ca bnh tuy phc tp nhng thng din bin di ba hnh thc khc nhau: 3.6.4.1. Khi hon ton Cc nguyn nhn gy bnh b tiu dit hon ton, cc triu chng bnh bin mt, ri lon v c nng, tn thng v hnh thi t bo, m v cc c quan c phc hi, c th tr li trng thi bnh thng, kh nng lao ng v nng sut c phc hi hon ton. Ring i vi mt s bnh truyn nhim th kh nng phn ng ca c th thay i, pht sinh trng thi min dch i vi bnh va mc (bnh u, bnh t th). 3.6.4.2. Khi khng hon ton Bnh khng ht hn, cc nguyn nhn bnh b tiu dit nhng khng hon ton, n c th c tr trong cc t bo, c bit l trong cc t bo thc bo hoc mt khu vc no m khng pht huy tc dng. Ngoi ra, khi khng hon ton cn gm: - li d chng: bnh ht nhng hu qu v gii phu v chc nng th vn

cn lu di (sau vim no tr khn gim st; gy xng lin nhng c d lch, kh c ng, vim ni tm mc ht nhng li d chng hp van tim, xut huyt no a n lit mt chi,). - li trng thi bnh l: din bin rt chm v i khi c th xu i, kh khc phc. V d: do chn thng, b ct ct mt ngn tay; vt thng cn li so ln... 3.6.4.3. Cht Cht l giai on cui cng ca s sng, do ri lon cao m c th khng th thch ng c vi cc iu kin ngoi cnh. Cht c hai t ra hn l cht sinh l v cht bnh l. Cht sinh l: do tiu ha nng lng trong qu trnh sng gim dn theo tui tc, gi ci, suy nhc n mt giai on c th khng c kh nng thch ng c vi yu t ngoi cnh. 26 - Cht bnh l: c th phi tri qua mt qu trnh bnh l do cc nguyn nhn tc ng gy nhng ri lon nghim trng khng th khi phc c. Cht l mt qu trnh, trong trng hp in hnh gm cc giai on sau: + Giai on ngng cui cng: tim v h hp ngng tm thi (trong vng 0,5 - 1 ,5 pht), mt phn x mt, ng t m rng, v no b c ch, cc hot ng sng u b gii hn. + Giai on hp hi: xut hin h hp tr li - th ngp c, tim p yu, phn x c th xut hin trong thi k ny, hot ng ca tu sng mc ti a duy tr cc chc nng sinh l, c th ko di thi k ny t mt vi pht n na gi. + Giai on cht lm sng: hot ng ca tim, phi ngng, thn kinh trung ng hon ton b c ch. Thi gian cht lm sng c th ko di 5-6 pht, trong thi gian c th hi phc c. Cn nu khng hi phc c gi l cht sinh vt. + Giai on cht sinh vt: mi kh nng hi phc khng cn na, ri lon ch yu h thn kinh trung ng. Trong cht sinh vt, cc c quan, t chc trong c th khng cht cng mt lc m trc tin l h thn kinh cao cp ri n tun hon, h hp... Nhng nguyn nhn chnh dn n cht: + Ngng hot ng ca tim nh lit tim, v tim, tc mch. + Ngng h hp, lit trung khu h hp do xut huyt no, thiu mu hnh tu, b ng c. 3.7. C ch phc hi sc kho Sau mt qu trnh bnh l th c th vt bnh c th phc hi c sc kho. Sc kho ch c phc hi sau khi nguyn nhn gy bnh ngng tc ng, trng thi c th khi tr li bnh thng, tnh hon chnh v gi tr kinh t ca n c phc hi. Khi yu t gy bnh tc ng th c th lun lun c phn ng bo v hay thch ng. C ch ny c vai tr quan trng trong s phc hi sc kho. V d: Yu t bnh nguyn kch thch ln nim mc ming, khi c th c phn ng tng tit nc bt v dch nhy. Nu yu t bnh nguyn tc ng vo nim mc mt th phn ng tit l c tng cng; tc ng vo ng h hp th phn ng ho, ht hi; tc ng vo ng tiu ha s gy nn. Trong c th xut hin phn ng min dch khi b nhim khun, phn ng lnh vt thng, ng mu khi t chc b tn thng, rch nt. C th cn c phn ng b p nhng c quan c tng cp nh thn, phi, mt. Khi chc nng ca mt trong cp c quan b tn thng th chc nng ca c quan kia s tng cng hot ng nhm b p li Ring trong h thng tun hon, khi b mt mu huyt p c khi phc mt cch nhanh chng do phn ng co huyt qun, tng ht nc vo lng mch, tng nhp

tim v h hp, tng hot ng ca cc c quan to mu, hoc khi hm lng oxy trong mu gim, gy ri lon trao i cht dn ti s ng cc sn phm trao i trung 27 gian, cc sn phm ny c toan tnh nn lm gim lng kim d tr trong c th, dn ti hin tng nhim axit, gy ri lon hot ng ca h thng thn kinh trung ng, ri lon chc nng ca cc c quan khc nh tng h hp nhanh chng o thi axit hi, tng gi mui kim ti thn iu ho axit - baz. C ch bo v ca c th khi b nhim khun l tng hot ng ca h thng li ni mc, tng cng vic to ra khng th, tng hin tng thc bo ca cc bch cu. Qua cc giai on ca bnh, cng phn ng bo v c th c th khc nhau, c khi mc cao, khng ng b c hi cho c th nh hin tng st l phn ng bo v ca c th, n lm tng sinh khng th, tng kh nng thc bo ca bch cu nhng nu st qu cao c th gy nguy hi n chc nng ca h thn kinh v h tun hon. H thng thn kinh trung ng c ngha rt ln trong vic bo v c th v trong qu trnh khi phc sc kho. iu c chng minh trong cc th nghim l khi gy m c ch v no, cc qu trnh tng sinh v ti sinh u gim, huyt p khi phc chm sau khi mt mu, gim phn ng min dch... 4. TNH PHN NG CA C TH V BNH L CA QU TRNH MIN DCH 4.1. Tnh phn ng ca c th 4.1.1. Khi nim v tnh phn ng ca c th Trc tc ng ca mt kch thch no (gy bnh, hoc khng gy bnh), c th ng vt p ng li bng mt hay nhiu phn ng. Trc mt kch thch nht nh, c loi phn ng l chung cho nhiu loi, v d: ng t co nh li khi nh sng cng chiu vo vng mc; tng glucoza huyt khi au n... C loi phn ng ch l chung cho cc c th trong mt loi; v c loi phn ng ca c th (khng hon ton ging nhau gia cc c th ca mt loi). V d, phn ng chung ca mi ngi l tng nhp tim khi b stress nhng c ngi tng qu nhiu (qu hi hp, lo lng), ngc li, c ngi li tng rt t. Nu nhiu c th c chung mt phn ng trc mt kch thch, ngi ta xp h thnh nhm v thnh kiu phn ng. a s cc phn ng in m du vt di truyn mang tnh bm sinh nhng cng c nhiu phn ng hnh thnh trong qu trnh sng, chu nh hng ca tui, gii tnh, trng thi thn kinh-ni tit, mi trng, thi tit,... Vy tnh phn ng l tp hp cc c im phn ng ca c th trc cc kch thch ni chung v trc bnh nguyn ni ring. Tnh phn ng khc nhau c th lm qu trnh bnh sinh mi c th v mi nhm khng ging nhau, a li cc kt qu khc nhau (tt, xu, nng, nh). 4.1.2. Nhng yu t nh hng n tnh phn ng 4.1.2.1. Thn kinh - Trng thi v no: Nu v no trng thi hng phn, thng to ra nhng phn 28 ng mnh v nu c ch th ngc li. Con vt b gy m p ng km vi cc kch thch (tim adrenalin, mt mu,...) so vi khi n cn tnh. Loi hnh thn kinh: loi hnh thn kinh mnh cn bng th tnh phn ng mnh, nhanh chng; loi hnh thn kinh mnh khng cn bng th tnh phn ng mnh nhng ko di; loi hnh thn kinh yu th tnh phn ng yu. - Vai tr thn kinh thc vt: nu kch thch thn kinh giao cm thy tng qu trnh

trao i cht v tng tnh phn ng ni chung i vi protein l, vi khun, hormon. Cn nu kch thch thn kinh ph giao cm th s tng cng vic to ra khng th, tng phn ng bch cu, tng kh nng ngn cn ca gan v h thng bch huyt. 4.1.2.2. Vai tr ni tit Cc tuyn ni tit nh: tuyn yn, tuyn thng thn, tuyn gip trng, tuyn tu u nh hng n tnh phn ng ca c th nhng ch yu l tuyn yn v v thng thn. Theo nh bc hc Hans Selye: Bt c mt tc ng mnh no tc ng vo c th u gy ra mt chui phn ng. Chui phn ng ny kt hp vi nhau thnh hi chng chung m c s hot ng ca n l cc tuyn ni tit. C th l hom lon ca tuyn yn adrenocorticotropic hormon (ACTH) v v thng thn. Khi b kch thch mnh th cc trung tm di th tit ra mt s hom lon thn kinh (hay yu t gii phng), cc hormon ny c dn ti tuyn yn bng ng mu lm tng tit ACTH v cortisol v sau tit STH dn n kch thch tit ra aldosteron. * Vai tr ca ACTH v cortisol: c tc dng chng hin tng vim v chng d ng Chng hin tng vim c hiu hn ch cc phn ng thc bo, c ch pht trin cc t chc lin kt, t chc ht, gim tnh thm ca thnh mao mch, cho nn lm gim hin tng ph n v tit dch. Mt khc ngi ta thy n hn ch s hnh thnh mao mch tn to, gim vim c hiu, lm thoi bin cc t chc bch huyt, lm tan v cc tng bo, lympho bo dn n gim khng th. * Vai tr ca STH (Somatotropic hormon) v aldosteron: c tc dng i lp vi hai nhm hormon trn. STH lm tng qu trnh vim, kch thch t chc lin kt tng sinh qua chng nhim trng, chng hoi t t chc. STH lm tng t chc bch huyt, tng tng hp globulin v khng th. Aldosteron ch yu iu ho nc v in gii, ngc li ca cortisol tng tnh vim, tng sinh cc t chc x non ca t chc ht, pht trin mnh mao mch, tng cng phn ng thc bo, gi li ton kali v con natri. 4.1.2.3. La tui ng vt non, h thn kinh c bit l h thn kinh cao cp cha hon thin cho nn phn ng gy ri lon iu ho nhit rt mnh, hng ro min dch chng nhim trng nim mc, da cha hon chnh. ng vt non khng mn cm vi mt s 29 bnh v n c min dch l do c m truyn cho -globulin qua nhau thai hoc qua sa m, phn ng thc bo ca ng vt non yu. ng vt trng thnh, tnh phn ng c tng cng pht trin theo s pht trin hon thin t chc ca c th, c bit l ca h thn kinh v hng ro bo v ca da, ca nim mc. Kh nng sn xut khng th mnh lit, tnh phn ng mnh m in hnh, nhiu khi d i, vt thng mau lnh, sc kho nhanh hi phc. ng vt gi yu, tnh phn ng km v h thn kinh, hng ro phng ng b suy gim, bnh tin trin khng r rt, khng in hnh, phc hi chm, vt thng kh lnh, t l cht cao. 4.1.2.4. Yu t v mi trng bn ngoi Tiu kh hu chung nui nhim lnh lm cho sc khng ca con vt gim dn n bnh nhim nng. - Cc ha cht tc dng lu cng gy thay i tnh phn ng. V d. Ung ru nhiu gy hin tng x gan, vim d dy lm cho kh nng phng bnh gim, chng vi khun km.

- Tia phng x lm gim sc khng, ch yu l dit t bo gc tu xng. - Dinh dng: tnh trng dinh dng c nh hng su sc n tnh phn ng ca c th. i v bnh dch i song song vi nhau. + Protein l thnh phn quan trng trong khu phn n ca ng vt. Nu thiu protein lm pht sinh nhim trng, nu thiu nng dn ti ph, d pht sinh bnh lao. + Thiu vitamin A lm gim sc khng ca nim mc, gic mc gy ra mt lot cc bnh nh vim gic mc, vim hng, nt n da. + Thiu vitamin B lm yu cc hot ng thc bo, nh hng n qu trnh oxy ha ca t bo, lm cho con vt chm ln, gim to mu sinh ra bnh ci cc. + Vitamin C y tng sc khng, thiu vitamin C lm gim sc khng, c bit l trong trng hp nhim khun trong bnh truyn nhim. + Vitamin D nh hng ti s mt cn bng khong dn ti bnh ci xng, mm xng. Ni chung dinh dng thiu biu hin cc triu chng sau: nhit khng cao ngay c khi bnh cp tnh nh cm, vim phi, phn ng bch cu yu hoc l khng c. Hiu gi ngng kt ca cc phn ng huyt thanh hc yu, c khi m tnh. Cc triu chng lm sng bn ngoi yu km, c th khng nhn thy, bnh tin trin nng ko di dai dng, t l cht cao. V vy chm sc h l dinh dng tt c tnh quyt nh tnh phn ng trong qu trnh bnh l. Ngoi ra yu t gii tnh cng nh hng n c th. Trong y hc, n ng hay 30 mc bnh d dy, lot hnh t trng hn l ph n; n ng hay b nhi mu c tim, u c phi hn l ph n. ph n hay gp vim v, ti mt, u c v. 4.2. Bnh l ca qu trnh min dch 4.2.1. Khi nim v min dch bnh l Min dch l trng thi ca ng vt khng mc phi tc ng c hi ca vi sinh vt, trong khi vi sinh vt gy bnh cho cc loi vt khc hoc cho con vt cng loi, trong nhng iu kin ly lan hay truyn bnh tng t. Min dch l mt kh nng khng cng ging nh nhiu kh nng khng khc (vim, su ca c th, trong nhng trng hp nht nh, phn ng khng c th tr thnh c hi cho c th. chnh l min dch bnh l. 4.2.2. i cng v p ng min dch Trc s tn cng ca cc yu t gy bnh bn ngoi, c th sinh vt c mt lot nhng kh nng khng khng c hiu v c hiu. Kh nng khng khng c hiu l hng ro vt cht ngn cch bn ngoi v bn trong l da v nim mc, l cc cht tit nh m hi, dch nhy, l cc t bo chuyn trch bn trong c th nh cc thc bo v cc cht thot c bit gi l khng th khng c hiu nh b th lizin, cht propecdin v opsonin. Kh nng khng c hiu l nhng cht thot gi l khng th c hiu do c th tng hp sn hay n c sn xut ra di tc ng ca mt s cht gi l khng nguyn. 4.2.2.1. Khng nguyn a) Khi nim Khng nguyn l nhng d cht i vi c th nh vi khun, vi rt, c t...bn ngoi vo c th ng vt hoc ngi th kch thch c th sn sinh ra nhng cht c bit c phn ng i lp vi chng gi l khng th. Khng th sinh ra s kt hp mt cch c hiu vi khng nguyn tng ng.

b) c tnh ca khng nguyn - Tnh c hiu: c hiu ca khng nguyn l c im nh khng nguyn c th phn ng mt cch c hiu vi khng th dch th hoc khng th t bo do khng nguyn c nhm quyt nh. Nhm quyt nh khng nguyn l phn b mt khng nguyn c kh nng lin kt mt cch c hiu vi phn t khng th hoc t bo lympho mn cm. Cc axit quan c phn phi trn b mt ca khng nguyn hnh thnh cc nhm quyt nh; cc nhm ny chi phi cc c quan sinh khng th, to loi khng th c hiu n khp vi khng nguyn . - Tnh l ca khng nguyn: Khng nguyn cng khc xa loi sinh vt nhn khng nguyn bao nhiu th kh nng sinh khng th cng mnh by nhiu. V d: Ly huyt 31 thanh ngi m tim cho b th c tnh khng nguyn mnh hn l khi ly huyt thanh d tim cho b. Khng nguyn con vt hon ton khc loi gi l d khng nguyn - l khng nguyn mnh. Nhng sinh vt cng mt loi c nhng khng nguyn khc nhau gi l ng khng nguyn. Tuy nhin, tnh cht l ca khng nguyn cng ch l tng i v nhiu khng nguyn c ng thi trong nhiu sinh vt khc nhau, v d nh khng nguyn nhm mu B c ngi v c trong ht na, hay khng nguyn H c trn hng cu ngi v hng cu ln. - Khng nguyn c phn t lng cao: Thng thng cc khng nguyn c trng lng phn t ln v thng o thi chm lm tng kh nng mn cm ca c th. V d: protein ca huyt thanh nh albumin (TLPT: 60.000), IgG (TtPT: 160.000), IgM (TLPT: 90.000), Cc phn t cc ln nh vi rt thuc l (17.000.000) l nhng cht khng nguyn mnh. Khng nguyn phi l nhng cht m c th tiu c nhng li tn ti lu trong c th. Nhng cht tr khng tiu c nh methyxeluloza khng sinh khng th c l v c th khng nhn din c cu trc ca cht ny, cho nn khng thng tin cho t chc c thm quyn tng hp khng th. Nhng cht tiu qu nhanh nh cht c trng lng phn t nh cng khng c kh nng sinh khng th v chng c o thi ra ngoi qu sm cng khng kp cho c th nhn din. c) S phn ca khng nguyn trong c th vt ch Khng nguyn a vo c th vt ch bng bt c ng no, trc tin xut hin trong mu ri n mt s t bo. Trong mu, khng nguyn ho tan trong mu (t 10- 15 pht) sau khuch tn ra khoang gian bo, m khng nguyn h nhanh trong mu v ko di vi ngy ri t phn hu t t v t nhin bin mt v khng th bt u xut hin. Sau thy khng nguyn t chc lin vng ni mc trong nhng hch gn ng xm nhp ca khng nguyn nht ( cc hch bch huyt ngoi vi nu l tim bp), ri n cc ni khc. Nh vy khng nguyn c t bo ca t chc ny n i. d) Nhng yu t nh hng n tnh sinh khng th ca khng nguyn - Liu lng: Trong min dch vi khun, ngi ta nhn thy tim chng liu nh v nhiu ln tt hn l tim mt ln liu ln. Trong gy min dch ung th thc nghim li thy l nu a cc t bo ung th vo hoc qu nhiu hoc qu t th u khng gy c min dch. - ng vo ca khng nguyn: khng nguyn c th c a vo bng nhiu ng khc nhau m vn c th gy c min dch nhng n khng b bin tnh hoc hu hoi trong khi xm nhp vo c th vt ch. Cc khng nguyn dng bi, bt

phn hoa, khi, c th qua ng h hp. Vi khun, vi rt c th qua da, nim mc h hp, tiu ha. 32 - Vai tr ca t cht: Tnh khng nguyn ca mt cht c th c tng cng nu kt hp n vi mt t cht. C ch tc dng cha r rng nhng c th t cht gy vim ti ch tim lm cho khng nguyn lu tiu v c bit n kch thch mnh c quan sinh khng th. T cht thng l nhng cht tr kh tiu: du pHrafin, keo phn... 4.2.2.2. Khng th Khi nim: Khng th l nhng cht thuc loi cu n mch (globulin) c bit xut hin trong huyt thanh khi mt khng nguyn xm nhp vo c th, c th phn ng li bng cch sinh ra khng th chng li khng nguyn , lm cho khng nguyn mt tc dng gy bnh. Tnh cht c bit ca khng th l kt hp vi khng nguyn sinh ra n. Trc s xm nhp ca khng nguyn vo c th, vt ch c 2 cch p ng: - p ng min dch dch th: bng cch tng hp cc khng th ho tan trong huyt thanh. - p ng min dch qua trung gian t bo tng hp nn khng th c hiu, cc khng th ny lin kt cht ch trn b mt ca t bo sn xut ra n, khng ho tan trong huyt thanh gi l khng th c nh (khng nguyn t bo). a) Khng th dch th - nh ngha: Khng th dch th c th hiu nh tt c nhng cht dch gip sinh vt chng li cc yu t c hi xm nhp vo c th. + Khng th t nhin (khng th khng c hiu) c sn trong huyt thanh: , , lyzin, propecdin, h thng b th (c 9 loi t C1 n C9) dit khun. + Khng th c hiu bn cht ca n chnh l -globulin. Globulin min dch "Ig" (Immunoglobulin) do qu trnh min dch to ra. Theo nh ngha quc t OMS-1994 "Cc globulin min dch l tt c cc protein huyt thanh v protein nc tiu c tnh cht khng nguyn v cu trc ging nh globulin th c k hiu vit tt l Ig". Nh vy globulin min dch bao gm cc loi khng th c nhng protein c cu trc ging nh globulin min dch m n nay cha c bit r. - Cu trc khng th: Nh cc phng php v in di, sc k, chit tch, siu ly tm, min dch hp ph cho n nay ngi ta phn c 5 loi Ig trong khng th dch th. Tn Trng lng phn t m trong huyt thanh IgG hay M 150.000 1200-1400 mg% IgA hay A 170.000 100- 400 - IgM - M 900.000 50-200 - IgD - D 155.000 3-14 - IgE - E 195.000 0,1-0,14 - 33 - Khi nghin cu sinh thi hc th cu trc ca 5 loi ny u ging nhau, u gm 4 chui a peptit: 2 chui nng H v 2 chui nh L, ni li vi nhau bng "cu ni disunfua (s-s)" v ngi ta thy rng c tng chui nng ring cho tng loi min dch. Chui nng Gamma IgG Chui nng Alpha IgA Chui nng Muy IgM Chui nng Delta IgD Chui nng Epsilon IgE

S cu trc khng th (Theo Bc hc Porter) (KT: khng th; KN: khng nguyn; KHBT: kt hp b th) V tr kt hp khng th vi khng nguyn nm gia chui nng v chui nh u tn cng NH2. Nh vy, trn mt phn t globulin min dch c hai v tr kt hp khng nguyn. Thng khi kt hp vi khng nguyn th hai u tn cng m rng ra nh hai cnh tay mt n v khng th c th kt hp vi hai n v khng nguyn. l trng hp khng th hon ton tc a ha tr (nh IgM). Do khng nguyn cng c nhiu trung tm hot ng cho nn khi kt hp ny s bt vo nhau m thnh mt mng li lm cho s kt hp d lng ng trong dung mi di hnh thc ln bng, kt ta, vn my... Khi hai cnh khng m rng lm cho mt n v khng th ch c th kt hp vi 1 n v khng nguyn th gi l khng th khng hon ton hay khng th n ha tr. Cho nn kt hp KN-KT s khng ln lng ng. - c im v phn loi khng th Khng th hay globulin min dch l nhng thnh phn ca thot huyt thanh nn d b nhit (700C), cc cht axit, kim v men ph hu. IgG: Phn ln khng th l IgG, chng c hot ng hu ch l trung ho c t, to phn ng ngng kt khi gp khng nguyn tng ng, phn ng opsonin ha v khi kt hp vi b th th lm tan vi khun. Hot ng gy tn thng cho sinh vt l to phc hp khng nguyn-khng th v ng li ti cc t chc v gy tn thng ti ni . 34 IgA: ch yu nm trong thnh phn ca cc dch tit nh sa u, nc bt, dch rut, v cc hch ngoi tit cha rt nhiu tng bo sn xut IgA. Khng th ny c kh nng trung ho c t, to phn ng ngng kt v opsonin ha, gip c th chng li cc khng nguyn c b mt cc nim mc v gi mt vai tr ng k trong min dch ti ch. IgM: l loi khng th hnh thnh sm, thng c t l cao khi IgG thp. Loi khng th ny c hot ng hu ch v gy tn thng gn ging nh IgG. IgE: l loi khng th thy tng trong cc bnh qu mn nh hen, ni m ay... Khng th ny tc ng lm thay i tnh thm ca thnh mao mch. IgD: cho n nay cha bit r tc dng v ang c tip tc nghin cu. b) Khng th c nh (khng th t bo) Khng th c nh l nhng khng th c gn ngay trn b mt t bo lympho T sn xut ra chng. Nhng t bo lympho i t tu xng n tuyn c c hun luyn thnh t bo lympho T. Hin nay ngi ta cha th tch loi khng th ny ra khi t bo nn cha bit c cu trc ca n. Khi gy mn cm cho ng vt bng khng nguyn to min dch c nh (nh mnh da ghp, vi khun lao) th mt nhm t bo mi sinh sn t t bo tuyn c (T) c hnh thnh - ngi ta gi chng l t bo effector. Sau khi mn cm khng nguyn 1 -2 ngy, cc t bo ny xut hin vng tuyn c v cc c quan 1ympho ngoi bin nh lch, hch (c bit tp trung nhiu vng tu ca lch) - l nhng effector c hiu. Mt khc trong qu trnh min dch, mt s thnh phn ca khng th v b th cng c tc dng hot ha mt s t bo n nhn, i thc bo, t bo Kuppfer. Cc t bo ny cng tr thnh hot ng nhng khng do s kch thch ca khng nguyn, ngi ta gi chng l nhm t bo effector khng c hiu.

c) H thng tng hp khng th v s hnh thnh khng th - H thng min dch Hin nay, ngi ta bit r l mi t bo t chc lympho u bt ngun t loi t bo gc ca tu xng gi l t bo M. Trong thi k bo thai, nhng t bo gc M (muclocyte) s n tr ng ti hai tuyn ngoi vi: tuyn c v tuyn Bursa Fabricius gia cm (cn cc ng vt c v th c l nhng tuyn tng ng nh mng Peyer rut v rut tha, amidan...) Loi t bo tuyn c i ra s n c tr ti vng cn v ca cc hch ngoi vi: l nhng t bo T v chng ph thuc vo tuyn c. Nu ct b tuyn , qun th t bo T ny s gim rt r rt (Miller, 1961) v mi p ng min dch qua trung gian t bo s mt ht (nh phn ng loi mnh ghp d en). Nu em tuyn c ng tin 35 ghp li cho con vt ct b tuyn y th s lng t bo T li tr li nh c cng nh cc p ng min dch qua trung gian t bo. Cc t bo lympho T (ch T l ch vit tt ca ch Thymus c ngha l tuyn c) trong khi di hnh trong mu, nu gp khng nguyn trc tip hoc qua i thc bo trnh din khng nguyn th n s tr thnh qun th t bo lymph T mn cm v khi tr v hch ln cn gn nht s bit ha thnh cc nguyn bo ln, phn chia thnh mt qun th lympno mi, l nhng t bo lympho c hot tnh min dch. Mt s t bo lympho ny li c th ri hch u tin ny n cc hch khc trong c th v li sinh ra nhng qun th t bo lympho c hot tnh min dch na. Sau cng, mt s t bo lympho c hot tnh min dch s lu hnh trong mu ngoi vi, s n ch c khng nguyn nu cn, to nn p ng min dch qua trung gian t bo. Ti ch , s kt hp khng nguyn vi t bo T c hot tnh min dch s dn n s tiu dit khng nguyn nh mt lot nhng cht do cc t bo T ny tit ra, tn chung gi l lymphkin ng vai tr quan trng trong hin tng di ng chm. Loi t bo ti Fabricius vo mu ngoi vi th n khu tr ti v ca hch v gi chung l t bo B (B l ch vit tt ca ch Bursa c ngha l ti) v n ph thuc vo ti Fabricius. gia cm, nu ct b ti ny, lng t bo B s gim mt, vng v hch khng c t bo v khng th dch th trong huyt thanh gim r rt, p ng min dch dch th khng c (Gch, 1953). Khng nguyn khi xm nhp vo c th, b t bo i thc bo n, ri di chuyn n hch gn nht, y cc t bo lympho B vy ly, tng sinh pht trin thnh nhng t bo a pyronin v tng bo. S pht trin t chc ny mnh nht khi khng th c sn xut cao nht. Nh vy l r rng nhng t bo lympho B v hnh thi bit ha cao nht ca chng l nhng tng bo, l loi t bo tng hp khng th dch th v chu trch nhim v p ng min dch dch th. Ngoi ra, h thng t bo lympho T t nhiu ng vai tr h tr cho h thng B, v trong th nghim ct tuyn c, khng nhng dng T tuyt sn m c dng B cng gim st hot ng. Khng th dch th khi gp khng nguyn s sinh ra phc hp khng nguyn-khng th c tc dng trung ho khng nguyn, tiu dit n v ng thi kch thch mt s t bo khc nh mastocyte, bch cu i kim tit ra cc ha cht trung gian nh histamin, serotonin... to nn nhng phn ng thy trong p ng min dch dch th (phn v...). - S hnh thnh khng th Trc tc dng kch thch ca khng nguyn, c th sn xut khng th ngay sau mi tim u tin. Ngi ta c th thy c khng th dch th xut hin trong mu vo ngy th 4-5 sau khi tim khng nguyn. i vi p ng min dch qua trung

gian t bo th theo a s cc tc gi, phn ng xut hin sm hn, l vo ngy th 3. T l khng th tng dn vo tun th ba, sau m khng th khng tng v c th gim dn. Nng khng th trong mu gim dn thay i tu theo loi khng 36 nguyn. Nu sau ba tun li dng khng nguyn kch thch li th khng th c tng hp nhanh hn v s lng cao hn. d) Nhng yu t nh hng n qu trnh tng hp khng th Ngoi nhng yu t thuc v khng nguyn k trn (liu lng, ng vo, t cht), c mt s yu t sau y nh hng r rt n vic tng hp khng th: Phn ng th pht (hi tng hay nh) Tim nhc li khng nguyn cho mt con vt tim mt ln khng nguyn ri th t l khng th s tng sm v nhiu hn l ln u (c th gp n hn 100 ln). Cng ca phn ng ln hai tng theo thi gian k t mi tim th nht, n thi hn ti a l khong 30 ngy trn th v chut. Phn ng ko di t 100 n 300 ngy. Phn ng nh ny c th tn ti nhiu nm sau mi tim th nht. l nh nhng t bo lympho T hoc B, sau khi tip xc vi khng nguyn, tr thnh nhng t bo k c khi khng nguyn vo ln sau th s lp tc tng sinh thnh dng t bo c hot tnh min dch ng o gy nn phn ng nh y. - Mn cm vi nhiu khng nguyn Nu tim nhiu khng nguyn ng thi th nhiu loi khng th tng ng cng ng thi c to ra vi mc ngang bng hoc nhiu hn khi tim khng nguyn tng loi. l l do ca vic dng nhng vacxin a gi. Tuy nhin, nu cng mt lc tim khng nguyn liu mnh vi khng nguyn khc liu nh th c th ch c khng th tng ng vi khng nguyn mnh m thi (cnh tranh khng nguyn). Hin tng c ch ny thng xy ra nu tnh ha hc ca cc khng nguyn gn nhau. - Dinh dng v thn kinh ni tit S tng hp thot ni chung v khng th ni ring, b gim st khi thiu thot trong ch n nh i lu ngy, trong ri lon hp thu... Trong thc nghim thy thiu vitamin B v C cng lm gim khng th. Nh trn ni, tnh phn ng ca con vt quyt nh s hnh thnh khng th nhiu hay t, lu hay chng, mnh hay yu; m ni n tnh phn ng l ni mt cch tng hp v hot ng thn kinh ni tit v tnh di truyn ca sinh vt. Ring v ni tit th n nay, ngi ta bit kh r v vai tr c ch min dch ca trc tuyn ynthng thn Hon non corticoit tc ng ln t bo ang sinh sn nh t bo lympho T, n c nh hng lm ngng qu trnh sinh tng hp khng th, lm ngng qu trnh phng thch ra cht lymphokin. Tri li aldosteron kch thch ng ha protein tng sn xut ra khng th, m ngi ta thy phn ng sinh min dch l phn ng sinh hc c lin quan n tnh di truyn. Cho nn trong thc nghim cng c th to c nhng gia sc sinh khng th mnh bng cch chn lc nhng gia sc c kh nng sinh min dch cao lm ging. - Nhng yu t bn ngoi khc 37 Nhng cht thuc chng ung th nh thuc chng phn bo, thuc alkyl ha, tia phng x... u c tc dng c ch min dch lm gim tng hp khng th Hin nay ngi ta thy c mt s loi vi rt chng li s min dch nh vi rt HIV ngi, vi rt IBD gy bnh Gumboro gia cm. Ngoi ra, ngi ta cng thy ch__________t Prostaglandin c ch t bo lympho T v B tng hp khng th.

Bn cnh , mt s cht gy c ch t chc lin vng ni m nh cc cht mu trung tnh, cacbon keo... cng c tc dng km hm qu trnh tng hp khng th, c l thng qua vic c ch cc i thc bo. e) Nhng gi thuyt v sinh tng hp khng th - Thuyt thng tin hay thuyt khun Do Breinl v Haurowitz (1930) xng v nhiu nh nghin cu v sau pht trin thm nh Alexander (1931), Mudd (1932), PHuling (1940), Bumett v Fenner (1949), cho rng khng nguyn c tc dng i vi cc t bo c hot tnh min dch nh l mt ci khun v cc khng th s c sn xut theo kiu cch ca khun . Ban u, gi thuyt "khun trc tip" c ra cho rng khng nguyn vo nm trong t bo lymph nh l mt ci khun m phn t globulin phi n ly mu . Song gi thuyt khng gii thch c nhiu hin tng nh phn ng nh, dung th v t lit min dch. cho nn nm 1949, Bumett v Fenner ln u tin a ra thuyt khun gin tip cho rng khng nguyn l mt yu t bn ngoi gy nn s tng hp mt enzym thch nghi, enzym s xc tc s hnh thnh cc phn t khng th theo khun kh ca khng nguyn. - Thuyt chn lc Cho rng khng th sn c trong c th sinh vt i vi bt k khng nguyn no c trong thin nhin hay do con ngi sau ny tng hp ra v khi khng nguyn t nhp vo trong c th th s kt hp vi khng th tng ng lm tng cng qu trnh sinh tng hp khng th c sn. Nm 1964, Bumett a ra gi thuyt "chn lc dng t bo" cho rng trong m tuyn c gm hn 10.000 t bo khc nhau, mi t bo tng trng cho mt dng v sau ny v c kh nng tim tng i thnh tng bo sn xut ra mt loi khng th. S dng sinh ra mi loi khng th i vi mi loi khng nguyn c th c (t khng nguyn, ng khng nguyn v d khng nguyn). Ring i vi khng nguyn lun lun c mt vi mt m cao nh cc khng nguyn ca bn thn th chng s ph hu hay c ch cc t bo tng ng ngay t khi cn l bo thai, cho nn c th bnh thng khng sinh khng th chng cc t khng nguyn. Nhng dng t bo y c mnh danh l nhng dng cm. Thuyt chn lc dng gii thch c nhiu hin tng min dch nh dung th min dch, bnh t min dch, khng c gammaglobulin trong mu... Song v l ch khng thin nhin no c th d on c ht 38 nhng khng nguyn m con ngi tng hp nn. Sau ny Szilard cho rng ADN trong mi t bo c kh nng to ra mi loi thot (khong 30 vn loi), mi thot c k hiu trn mt en ca chui ADN gm mt b phn iu ho, mt b phn c ch. Mi khng nguyn khi vo trong t bo c tc dng gii c ch cho mt n tng ng v en c t do y s quyt nh tng hp khng th c hiu tng ng. Gn y nhng thnh tu nghin cu v cu trc globulin min dch cho thy, trong cc chui a peptit hnh thnh chui nng cng nh chui nh c mt phn tn cng NH2 rt thay i v trnh t cc axit quan, phn cn li t thay i, c bit chnh phn hay thay i ny li l ch khng th kt hp c hiu vi khng nguyn. Do , nhiu tc gi cho rng nhng t bo sinh khng th u mang hai hoc ba n n nh chng trnh tng hp mt kiu globulin min dch no nht nh. ADN ca cc en bn vng v khng b khng nguyn lm bin i. Nhng trong qu trnh phn bo, cc en c th xy ra nhng bin i bn thn. Nhng bin i

cc giai on nucleotit y do trao i cho gy nn, c th to nn nhng thay i th t cc axit quan trong phn thay i ca cc chui. Nh vy c th ni, t bo mm nguyn thu ch c n nh chng trnh sn xut globulin min dch theo mt qu trnh bnh thng nh sn xut cc loi protein khc m thi nhng s trao i cho gia cc bn trong phn bo thi k phi sinh sn xut ra rt nhiu cc t bo lympho c kh nng tng hp nhng globulin min dch tng t, ch khc l ch c nhng on axit qun khng ging nhau c thch nghi vi nhng khng nguyn khc nhau. 4.2.2.3. B th D khng phi do p ng min dch sinh ra nhng b th gi vai tr quan trng trong phn ng min dch, v n kt hp vi nhiu h thng khng nguyn-khng th v gip cho vic tiu dit khng nguyn tt hn, nhanh hn. K hiu b th l C, b th l mt phc hp dch th khng __________c hiu, c t nhin trong c th. l mt h thng gm chn th men t C1 n C9, tc dng dy truyn theo th t 1-2-3-4-5-6-7- 8-9. Khi b th lin kt vi phc hp khng nguyn-khng th th pht huy mt lot nhng tc dng sinh hc ca n: Tiu khng nguyn b gn khng th c hiu, nht l nu khng nguyn l t bo. Ln u tin, ngi ta pht hin tc dng ny i vi hng cu. Khi trn hng cu cu vi khng th chng hng cu cu (cn gi l dung huyt l) th ch c hin tng ngng kt m khng c tan mu. Nhng nu em cho thm b th vo th mng hng cu s b b th chc thng, huyt sc t chy ra ngoi. - Chun b cho hin tng thc bo: mt phc hp khng nguyn-khng th kt hp b th d c cc t bo nh bch cu a nhn trung tnh, i thc bo... n i 39 hn l khng c b th. Ngoi ra, s hot ha h thng b th ko theo hot ha nhng h thng ng mu v h thng khn huyt tng lm tng cng hot ng thc bo. - S kt hp b th vo khng th lm tng cng qu trnh lin hp mt s khng nguyn tc l y mnh s lin kt khng nguyn-khng th cn t do trong mi trng, c bit hin tng kt dnh min dch c tng cng. 4.2.2.4. S kt hp khng nguyn v khng th N l phn ng c bn ca qu trnh min dch. C ch kt hp: khi em khng th trn cng vi khng nguyn c hiu tng ng th hai th s kt hp vi nhau, nhiu khi c th nhn thy c bng mt thng di hnh thc nhng hin tng nh ln bng, kt ta, ngng kt. Trong trng hp khi khng nguyn-khng th kt hp ri m n li ho tan th c th dng nhng bin php gin tip nh theo di s tiu th b th, hay hp thu khng nguyn hoc khng th, trn mt nhng ht nh (hng cu, ht colodion...) lc khng th hoc khng nguyn s ngng t nhng ht ny. Cn i vi khng th c nh th ngi ta c th pht hin c bng phn ng qu mn: phn ng qu mn ni b. - Kt qu ca s kt hp khng nguyn-khng th thc cht n l mt phn ng bo v bi v do phn ng ny m khng nguyn mt tnh cht l ha v sinh vt ca n. Nu khng nguyn l vi khun, vi rt th khng th s ngng t n li lm cho n khng sinh si ny n hoc lm cho n b dung gii bi tc ng ca b th hoc n b tiu dit bi i thc bo.

Nu khng nguyn l c t hay thot l th khng th s kt ta chng li lm mt tc dng c, cht ta b tiu dit. Do mt tt ny m con ngi ng dng phn ng min dch trong cng tc phng v cha bnh. Nhng phn ng kt hp khng nguyn-khng th i khi n lm xut hin mt lot cc phn ng khc gy hi cho c th. V d: vim c hiu, ri lon vn mch, co tht c trn, tng sinh t bo. Nhng phn ng ny v c bn mang tnh cht bo v nhng i khi qu mnh li tr ln c hi cho c th. Phn ng kt hp khng nguyn-khng th n cng phng thch ra cc cht trung gian c hot tnh sinh l, tu theo khng th kt hp vi khng nguyn l khng th dch th hay khng th c nh. Cc cht trung gian ca khng th dch th: Khi khng nguyn kt hp vi khng th dch th u tin l n phng thch ra mt men tiu m diamin-oxydaza, men ny lm cho mt s cht trong t bo phng thch vo c th gy ra hin tng bnh l: 40 + Histamin c t bo mastocyte v bch cu i kim tit ra c tc dng tng tnh thm mao mch v co c trn. + Serotonin do tiu cu tit ra lm co c trn, tng tnh thm mao qun. + SRS-A (Slow reacting substance of anaphylaxis) do cc t chc phi tit ra c tc dng nh histamin nhng chm hn + Cc khn huyt tng ch yu l bradykinin, kallikinin do cc men tiu m nh plasmin, trypsin chuyn t cc globulin huyt tng thnh. Chng c tc dng lm tng sc thm mao qun tc gin mch - Cc cht trung gian ca khng th c nh: khi khng nguyn gy p ng min dch qua trung gian t bo th cc khng th c sn xut ra nm ngay trn b mt ca t ho lympho T l cc khng th c nh. Nu nhng khng th c nh ny gp nhng khng nguyn ln sau th phn ng kt hp khng nguyn-khng th xy ra v xy ra ngay trn b mt ca t bo ri n gii phng ra mt s cht c hot tnh sinh l gi chung l lymphkin m c th k mt s chnh sau: + Cht chuyn dng lympho bo LTF (lymphoblastic transforming factor) lm cho t bo lympho nh thnh nguyn bo v sinh si ny n thm ra. + Cht c ch i thc bo MIF (macrophage inhibitor factor) lm cho i thc bo khng i ra khi c ch kt hp khng nguyn-khng th. + Cht hot ha i thc bo MAF (macrophage activator factor) kch thch t bo i thc bo tng hot ng. Nhng ha cht trung gian ca khng th dch th cng nh lymphokin, bn thn lm tng tun hon ti ch v tp trung ti cc kh nng bo v c th (i thc bo, ng mu...) nhm nhanh chng tiu v loi khng nguyn ra khi c th. Song phn ng bo v nhiu khi cng lm cho c th kh chu, i khi nguy him na. 4.2.3. Min dch bnh l i cng Min dch bnh l bao gm nhng biu hin bnh l ca kt hp khng nguynkhng th (cn gi l d ng hc) v nhng ri lon qu trnh sn xut khng th. 4.2.3.1. Biu hin bnh l ca kt hp khng ngun - khng th (hin tng qu mn) Trong phn ng kt hp khng nguyn-khng th khng phi lun lun mang tnh cht bo v m nhiu khi cn biu hin c hi l chnh. Trng thi c gi l trng thi qu mn.

Trong thc nghim cng nh trong lm sng, trng thi qu mn thng thng qua cc giai on: - Giai on mn cm: tc l lc c th nhn liu mn cm cho n lc c th nhn 41 liu pht hin; thng t ngy th by tr i sau khi nhn liu mn cm. - Giai on qu mn: Sau khi nhn liu pht hin c th xy ra ngay gi l qu mn nhanh khi l khng th dch th, c th xy ra chm sau 2-3 ngy gi l qu mn chm khi l khng th c nh. - Giai on 3 : gi l giai on gii mn cm, l lc khng nguyn mt tc dng gy ri lon. a) Qu mn tc khc Tu theo loi khng th dch th m c th c nhng hin tng qu mn khc nhau i t phn ng cc b n nhng biu hin ton thn. Cc tn thng t chc cng c nhiu kiu khc nhau tu thuc vo bn cht l hc ca khng th v vo ni xy ra phn ng. Kt hp khng nguyn-khng th dch th to nn phn ng qu mn nhanh u c mt s nhng c im chung sau y: Phn ng xy ra nhanh sau khi tim liu khng nguyn pht hin (thi gian c th tnh bng giy hay pht). - Kt hp khng nguyn-khng th phng thch ra cc ha cht trung gian c hot tnh sinh hc nh histamin, serotonin, SRS-A... - Phn ng qu mn nhanh thng xy ra nhng b phn c nhiu c trn nh ph qun, thnh mch, thnh rut... C th c nhng hin tng qu mn nhanh nh sau: * Hin tng Arthus (sc phn v cc b) l phn v nhanh ti ch do Arthus tm ra (1905), biu hin vim cc tiu ng mch (vasculitis), trong phn ng ny khng th lu ng ch yu l IgE v IgM v n cng c s tham gia ca b th. Trong thc nghim: nu em tim huyt thanh nga cho th di da nhiu ln, cch nhau 5-6 ngy th t mi tim th bn, ch sau 15 pht n vi gi l bt u c phn ng ti ch tim nh vim , ph n, nhiu khi c km theo xut huyt v hoi t. V mt gii phu bnh th c vim huyt qun, thm nhim bch cu a nhn trung tnh. C ch sinh bnh ca hin tng ny l do khng nguyn c trng lng phn t ln cha khuch tn vo trong lng mch kp gp khng th ngay trong gian bo; phc hp khng nguyn-khng th ny hot ha yu t C3 ca b th lm cho h thng ng mu v h thng khn hot ng to nn mt vim. Bch cu a nhn do vim s phng thch ra cc men gy nn tn thng huyt qun. * Sc phn v, bnh huyt thanh v cc trng thi qu mn khc Sc phn v c th to thnh trong thc nghim khi ngi ta tim tnh mch cho ng vt mt loi protein l (lng trng trng, huyt thanh khc loi) gy cho con vt cht. Sc phn v c nh khoa hc Portier v Richet m t nm 1902 khi tim tinh 42 cht ca mt con hn bin cho ch ln hai, sau ln tim th nht khong 14-15 ngy th gy cht ch khng bo v c. Biu hin ca sc phn v l c s khc nhau nhiu loi ng vt, m phn ng c bn ca sc l s co tht c trn cc b phn ni tng. V d: chut lang th thy con vt kh th, xanh tm, giy gia ri cht, khi m thy nhu m phi khng xp do ph __________qun b co tht. ch co tht c trn tnh mch

c bit l tnh mch gan, cho nn ch au, t mu gan, gim huyt p cc c quan khc dn ti cht. Cn nga, mo, chut nht biu hin ging chut lang. chut cng tng tnh thm thnh mch dn ti xut huyt, th t mu ng mch phi gin tm tht phi. Khi quan st trn knh hin vi cc phc hp khng nguyn - khng th lng ng trn mao mch phi, ko theo s t tp cc bch cu, cc tiu cu lm tng huyt p phi hnh thnh cc huyt khi lm cho mu khng lu thng c v li dn ti lp qun v cht. ngi c mt trng thi bnh l tng t gi l bnh huyt thanh, gp khi tim huyt thanh iu tr d loi (huyt thanh nga chng un vn, chng bch hu...). Tt nhin bnh huyt thanh in hnh xy ra nhng ngi dng huyt thanh iu tr d loi mt ln trc ri, trong c th sn c khng th chng li. Triu chng xy ra mnh, rt cp tnh v bnh nhn c th cht do sc. Nhng c loi bnh huyt thanh xy ra ngay khi tim huyt thanh iu tr ln u tin, triu chng thng xut hin vo ngy th 6 sau khi tim vi ni mn, pht ban, au khp, i ra albumin. D ng nhanh l hin tng qu mn tc khc, thng ch xy ra trn ngi mt cch bt thng. Khng nguyn l loi yu v xm nhp theo ng t nhin (h hp, tiu ha...) v t t. Biu hin bnh l thng co tht c trn v hi chng vim. V lm sng, d ng nhanh bao gm rt nhiu bnh cc c quan khc nhau. C th k mt s trng hp sau: + mt: ph mi mt d ng, ph vng mc, vim gic mc d ng. + mi: vim mi d ng c ph nim mc tit dch cha nhiu bch cu a axit, nim mc qu sn, sn si, nu c nhim khun ph th s chy m. + tai: vim tai, vim tin nh d ng. + phi: hen ph qun (co tht ph qun, ph v tit dch lm hp thm lng ph qun gy ting rn, kh th, xanh tm, thng xy ra sm trc 20 tui). + da: vim da d ng, ni m ay, l sn. + ng tiu ha: vim mm, vim d dy, rut, nn theo chu k. + khp: vim ph khp, cc th thoi ha khp. + thn kinh: nhc u kiu bn thin u thng, co git th ng kinh, st ma 43 (st theo ma v c l khng nguyn l phn hoa, ph nim mc mt, mi, thm nhim bch cu a axit, tng tit dch). + mu: ban xut huyt, gim tiu cu, bch cu. - V c ch ca sc phn v cng nh bnh huyt thnh hay cc trng thi d ng nhanh l do kt hp khng nguyn-khng th (IgG, IgM v IgE). Tu theo loi khng th no ' ch yu m ta c th c bnh cnh lm sng khc nhau. IgE c i tnh mnh vi t bo nn thng bm vo cc t bo chung quanh cc c trn cho nn nu khng th ny chim a v tri th cc phn ng xy ra mt t bo v cc biu hin c tnh cht phn v r rt (co tht c trn, tng tit dch...). Nu l cc khng th IgG, IgM th ch yu hnh thnh nhng phc hp min dch tun hon trong mu ri lng ng mt t chc, c quan no to nn mt trng thi bnh l m hin ny cc tc gi gi l "bnh cc phc hp min dch". Cc phc hp ny lng ng u s ko cc t bo lymph n v tit ra lymphkin, phc hp cn hot ha C3 ca b th theo con ng tt, t c th gy tan t bo, ko cc bch cu a nhn trung tnh tit cc men tiu m, hot ha h thng ng mu, gy ng fibrin ti ch v phng thch cc khn huyt tng. Tt c nhng thay i ny s gy vim ti ch.

D ng thuc: mt s thuc khi vo c th c kh nng gn vi protein ca c th to thnh mt khng nguyn hon ton, kch thch c th sinh khng th dch th hay t bo. V d: thuc penicilin khi vo c th thoi ha thnh nhm penicilloyl gy d ng nhanh c th lm cht ngi. b) Qu mn chm tr Hin tng qu mn chm tr cng nm trong min dch qua trung gian t bo. l phn ng c bit da, xy ra 24-48 gi sau khi c th mn cm c tip xc vi khng nguyn c hiu. Trong mu ca c th b qu mn chm tr khng pht hin c khng th dch th __________cho nn khng truyn th ng bng huyt thanh c. Nhng khng nguyn gy ra qu mn chm tr rt khc nhau nhng thng l nhng khng nguyn khng ho tan, t c kh nng khuch tn trong ton c th vt ch, v d nh nhng khng nguyn t bo. Sau y l lit k mt s khng nguyn gy qu mn chm tr hay gp: - Khng nguyn vi sinh vt: Tuberculin (lao); typhoidin (thng hn); c t bch hu trong phn ng Schick; Vi rt u; khng nguyn nm: histoplasmin, coccidiomicin; khng nguyn n bo (bnh do leishmania). - Khng nguyn cn trng: dch tit ca mui, ong. - Khng nguyn t chc d loi (trong phn ng loi thi mnh ghp). - Bn khng nguyn gy d ng do tip xc nh ha cht. - Mt s t khng nguyn trong bnh t min. 44 in hnh trong d ng chm l phn ng tuberculin. Sau 48 gi khi tim ni b 0,1ml tuberculin th nu c phn ng, vt ch c th st nh, ch tim s vim , cng; v mt gii phu bnh l th c thm nhim t bo lymph quanh v bn trong cc mao qun. Phn ng ny cng c th truyn th ng bng hn dch t bo lymph mn cam. D ng chm do ha cht xy ra khi tip xc nhiu ln vi ha cht nh thuc, cht do, cao su, x phng th b ni mn, sung huyt, ni phng gy hin tng vim kiu eczema. Ti ch vim c tn thng ni b, ph t bo v thm nhim bch cu n nhn. C ch sinh bnh ca phn ng d ng chm: Khng nguyn khi gp t bo lymph mn cm th sinh ra hai kt qu: + Kt hp khng nguyn-khng th hot ha b th ko theo hot ha h thng ng mu v khn huyt tng nh trong kt hp khng nguyn vi khng th dch th. + Kt hp lm t bo lymph tit ra nhng lymphkin to nn mt lot cc phn ng t bo (c ch d tn, hot ha i thc bo, chuyn dng lymph bo...). Phn ng loi thi mnh ghp: Trn c th ng vt khi tin hnh ghp cc t chc m cc t chc l d en th s xy ra phn ng loi thi t chc ghp ra khi vt ch, hin tng gi l hin tng loi thi mnh ghp. Trong qu trnh thc hin khi ghp mt t chc cho vt ch m khc trn ngi ta nhn thy sau 1 -2 ngy mnh ghp lin v chung sng vi vt ch nhng m ko di 1 -2 tun ch ghp thm nhim cc t bo lympho T, cc i thc bo, lm cc mch qun ti ch ghp c hin tng ng mu, hnh thnh cc huyt khi gy tc mch, ph, mnh ghp khng c nui dng hoi t v bong khi vt ch, nu tip tc ghp li th mnh ghp li bong nhanh hn. Hin nay ngi ta c th ghp da, ghp thn cho cc c th v mnh ghp chnh l ca c th hoc mnh ghp ng tin vi vt ch (ghp ca hai vt sinh i cng trng). Vic ghp da, ghp thn phi c k thut tin tin, dng cc phng php c

ch min dch bng cc ha cht, cc tia phng x th mnh ghp tn ti c lu hn. Bng 2. So snh s khc nhau gia qu mn tc khc v qu mn chm tr Qu mn tc khc Qu mn chm tr - Xy ra nhanh - Khng th dch th - Ho cht trung gian -Truyn th ng bng huyt thanh - Phc hp KN-KT i ti u gy bnh ti - Loi: Phn v. d ng nhanh - Xy ra chm - Khng th c nh trn t bo - Lymphokin - Truyn th ng bng hn dch t bo - KN-t bo mn cm gy bnh ti ch c khng nguyn - Loi: D ng chm, loi ghp 45 4.2.3.2. Ri lon qu trnh sn xut khng th a) Thiu nng min dch L trng thi bnh l trong p ng min ch ca c th gim st hoc khng c. S thiu ht ny c th ton b hay b phn i vi min dch dch th hoc i vi min dch qua trung gian t bo thi. N c th l bm sinh hay mc phi, hay l thiu ht khng c hiu nh thiu b th. - Suy gim min ch bm sinh: + C th ng vt sinh ra thiu t bo M hoc l t bo ny c rt , n gim ton b c hai loi t bo lympho B v T. Trong c th hu nh hon ton khng c t chc dng lymph, trong mu khng c globulin min dch. Cc phn ng p ng min dch dch th v min dch t bo u khng thy c. Cho nn con vt d b cht v nhim trng. + Thiu t bo lympho T: khng c tuyn hay c m khng c tiu th Hassal nn h thng lymph T khng c, nhng phn ng min dch qua trung gian t bo khng c, nhng phn ng min dch dch th vn cn. Con vt cng hay b nhim khun m cht. + Thiu t bo lympho B: Biu hin ngay trong huyt thanh thiu gamma globulin. Bnh ny ngi ta thy cng c th do di truyn m thiu B lympho bo, t ngi ta thy bn loi khng th IgM, IgA, IgD, IgE khng c, cn IgG c t bng 10% bnh thng dn n khng c p ng min dch dch th, lm c th lun nhim bnh, nu c b sung y-globulin cng ch ko di trong vi thng. - Suy gim min dch do tc ng t bn ngoi + Do nhim cc vi rt m n xm nhim vo h thng min dch ( ngi nhim vi rt HIV - Hu man Immunodeficiency Virus) gy bnh AIDS (Acquired lmmunodeficiency Syndrome). Vi rt: IBD virus (Infectious Bursal Disease), vi rt leuko, vi rt Marek tn cng ti fabricius. + Ngoi ra mt s vi rt khng tn cng vo h thng min dch nhng ng vai tr tng phm nh vi rt Ca r ch, vi rt dch t ln, vi rt dch t tru b lm gim sc khng ca c th.

+ Suy gim h thng min dch cn do cc hch ung th nh u c tnh dng lympho, u tu xng. + Cc ha cht c v c v hu c u tc ng lm dit t bo, chng phn bo, chng chuyn ha. + Cc cht phng x vi liu ln: tia X, tia . + Dinh dng: i, h thn, a chy mnh, x gan c chng... u c kh nng lm suy gim min dch. 46 b) Dung np min dch Tc l hin tng khng c min dch c hiu i vi mt s khng nguyn, m cc khng nguyn ny xm nhp vo c th vt ch t lc min dch cha trng thnh: giai on bo thai, s sinh; ln sau xm nhp vo c th vt ch th vt ch khng sn xut ra khng th chng li khng nguyn . Trong t nhin hin tng dung np min dch xy ra hai tr hoc hai vt sinh i ng tin cng trng do Owen tm ra nm 1950. Trong thc nghim nh khoa hc Medawar (1951) ly t bo lch, tu, hch ca ging chut CBA c mu lng nu tim vo thai 7 ngy ca ging chut A c mu lng trng. Sau khi chut A ra i v trng thnh c hai thng th ng ly da chut CBA nu ghp ln trn nhng con chut A trng c chun b ny. Vic ghp thnh cng; tri li nhm i chng gm nhng con chut A khng chun b th mnh ghp b loi thi nh ghp d loi khc. Ngi ta c th a khng nguyn cng vi cc cht c ch min dch th c hin tng dung np min dch khng lu. Cn nu a khng nguyn qu t hoc qu cao th c th khng sn sinh ra khng th gi l hin tng c ch min dch. C ch ca hin tng dung np min dch: Nhiu tc gi cho rng: khi a mt khng nguyn vo c th trong thi k bo thai (min dch cha trng thnh) cho nn khi tip xc vi khng nguyn n khng th phn bit c l khng nguyn ca bn thn hay ca c th khc, do khng sn sinh ra khng th m cn coi l thnh phn ca bn thn mnh, do vy khi a khng nguyn vo c th khng sn sinh ra khng th m dung np khng nguyn . c) Suy gim b th (Complement deficiencies) Ch thy ngi, chut lang, chut nht v th. ngi trong thnh phn thiu C5, C3 do ti nhim khun nhiu ln v hin tng ny ch thy mt s c th; chut nht thy thiu C5; chut lang thy thiu C4; th thy thiu CO, biu hin l tng nhim trng, gim sc khng. d) Gim chc nng thc bo ca i thc bo (Macrophage) v tiu thc bo (Microphage). Ch yu l do thiu men NADPH oxydaza trong cc t bo thc bo lm cho cc chc nng tiu t bo ca t bo thc bo gim (thy xut hin ngi). e) Ri lon sn xut khng th. Bnh t min dch: l hin tng c bit ca c th sn xut ra khng th hoc sn xut ra cc t bo lympho T min dch chng li m bo hay l cc c quan l thnh phn ca chnh mnh. mt s bnh: vim cu thn do c th sn xut ra khng th chng li mng c 47 bn gy vim thn, hoc bnh vim tinh hon v tinh trng hoc vim khp dng thp. V ngi ta c th gy bnh thc nghim bng cch (ng Mansugi) dng huyt thanh

vt c khng th chng thn th tim cho th dn n lm vim thn th. Cn ng Cavelti dng thn th cng vi c t ca lin cu khun tim cho th gy vim thn th. V c ch, c nhiu gi thuyt gii thch hin tng ny nh: - Khng nguyn l cng c cu trc vi khng nguyn ca bn thn hoc l c cu trc gn ging cho nn c th sn sinh ra khng th chng li khng nguyn l, ng thi dn ti chng li chnh bn thn n. - C s gii c ch dng lympho b cm cng l do nhim khun, m cc dng lympho b cm t sinh ra khng th. Hin nay ngi ta gii thch c th do yu t di truyn c lin quan n bnh sinh t mn cm. Cn gn y ngi ta li cho rng c s ri lon cn bng gia lympho bo T v lympho bo B sinh ra khng th chng li bn thn. Ri lon globulin min ch l bnh c tnh m n sn xut ra globulin c bit (in c bit) c cu trc gn ging IgA, IgE, IgG, IgD, IgM nhng khng c kh nng p ng min dch, v th c th d b nhim khun (thng gp nhng ngi gi m pht hin ra bng phng php in di). 48 Chng 2 SINH L BNH CC QU TRNH BNH L CHUNG 1. RI LON TUN HON CC B Tun hon trong cc c quan v trong cc t chc cng c th thay i trong nhng iu kin sinh l khc nhau. Khi mt c quan no tng hot ng th tun hon ni cng tng cng. V d: Khi c bp lm vic nhiu th lng mu ti cc c tng ln gp bi hoc khi tiu ha thc n d dy th mu ti d dy tng ln. Tun hon cc b mi c quan v t chc lin quan cht ch ti tun hon chung ca ton c th. Nu lng mu tng c quan t chc no th lng mu ni khc s gim i. Cho nn trong trng hp sinh l bnh thng s thay i ch nm trong lnh vc dao ng sinh l bnh thng v nhanh chng hi phc tr li bnh thng. Trong trng hp bnh l s thay i, ri lon tun hon phi do nguyn nhn hoc bn trong hoc bn ngoi kch thch. Ri lon tun hon cc b c th biu hin qua ri lon tun hon chung ca h tim mch v ngc li ri lon tun hon chung cng c th dn ti nhng bin i tun hon ca tng c quan hay b phn no trong c th. S iu khin tun hon, trng lc mch qun gin tip l h thn kinh thng qua dch th l tit t ca tuyn thng thn, tuyn yn. V vy ri lon tun hon cc b c th xy ra do ri lon chc nng ca bn cu i no, ca cc trung khu thc vt v cc u mt thn kinh thc vt ngoi vi nm trn cc mch qun. Cc cht c hot tnh sinh l trong c th tit ra trong qu trnh min dch, qu trnh vim nh: axetylcholin, cc quan nh: histamin, typHmin, adenosin triphosphat, axit lactic... cc cht ny tc ng ln mch qun thng qua cung phn x hoc gin tip tc ng ln thn kinh co c mch qun nh hng n trng lc mch qun. V d: histamin gy co cc tiu ng mch, gin cc mao mch; axetylcholin gy gin tiu ng mch; adrenalin gy co mch da v gin mch vnh. Ri lon tun hon cc b c th xut hin do thay i thnh phn cc cht in gii, nng axit, c bit l nng ca con H+. Khi tng axit ng mch gin, cn khi tng kim ng mch co, vi tnh mch th ngc li tng axit co mch, tng kim gin mch. Ri lon tun hon cc b thng mang nhng c tnh khc

nhau, thng biu hin mt s hin tng sau y: 1.1. Sung huyt cc b (local Hypercmia) Sung huyt l hin tng tng lng mu c quan, t chc cc b trong c th. C hai loi sung huyt: sung huyt ng mch v sung huyt tnh mnh 1.1.1. Sung huyt ng mch (Artenal Hyperemia) 49 1.1.1.1. Khi nim Mu ng mch y c quan, b phn no trong c th do cc tiu ng mch, mao mch gin ra mu dn vo nhiu, trong khi dng mu chuyn i (v tim) vn bnh thng. V d: vim , i nng mt , xu h mt , bng, xoa du nng, ngm chn vo nc nng... do sung huyt ng mch. 1.1.1.2. Nguyn nhn gy sung huyt ng mch Do nhng kch thch nh: c hc (khi mt b phn no trong c th b tc ng bi mt lc c hc th ti ni s b sung huyt ng mch), ha hc, l hc (cc tia phng x tc ng; trong c th ni no b kim hoc a xt mnh tc ng th ni b sung huyt ng mch), sinh vt hc (do tc ng ca c t vi khun); - Do tng mn cm ca mch qun i vi kch thch bnh thng (mn cm d ng mn cm vi nh sng); - Do tc ng trc tip ln thn kinh iu khin mch qun, trung khu vn mch hoc thn kinh thc vt. 1.1.1.3. Biu hin bn ngoi ca sung huyt ng mch - Ni sung huyt c mu xut hin do tng hm lng mu ng mch, m mu ng mch mang nhiu oxy nn mu ti; - Cc ng mch, tiu ng mch, tiu mao mch gin rt rng; Tng s lng mch qun c th nhn thy; Bt c mch t cc ng mch nh do mu cha y trong mch qun v huyt p tng; - Tng nhit ni sung huyt do tng dng mu n v tng qu trnh trao i - Vng sung huyt