H Min Dch Ca C Th Ngi
H min dch l h thng cc cu trc v qu trnh sinh hc trong mt c th bo
v bnh tt ca c th sinh vt bng cch xc nh cc khng nguyn l v git cht cc
vi sinh vt l, t bo bt thng.1. H min dch l g?
H min dch l mng li v cng phc tp ca cc t bo, m v cc b phn gip bo
v c th con ngi khi cc tc nhn xm nhp nh vi khun, virus, k sinh trng,
cng nh cc ri lon ca t bo.
H min dch to ra cc khng th v cc t bo c bit tn cng cc sinh vt l
thm nhp c th sng.
H min dch c xem l h thng bo v t nhin ca con ngi, c v nh hng ro
chn trc tc nhn xm nhp nh vi khun, virus, k sinh trng, nm; sa cha cc
t bo h hng; phng trnh ung th H min dch khe mnh s gip y li s xm nhp
ca cc tc nhn gy hi gip tr trnh c cc loi bnh, gip c th pht trin khe
mnh.
2. C ch hot ng ca h thng min dch
H thng min dch ca chng ta gm c 2 phn, c th chia lm h thng min
dch khng c hiu (MDKH) v h thng min dch min dch c hiu (MDH). Thut ng
min dch khng c hiu cn c cc tn gi khc nh min dch t nhin, min dch bm
sinh. Thut ng min dch c hiu cng c cc tn gi khc nh min dch thu c,
min dch thch nghi.
Cc p ng min dch khng c hiu (min dch t nhin) c hnh thnh rt sm t
khi em b mi c sinh ra, h thng min dch ny b c tha hng t m. Qu trnh
pht trin ca c th hon thin dn h thng min dch. H thng min dch t nhin
v h thng min dch c hiu b sung cho nhau bo v c th trc nhng tc nhn c
hi ca mi trng.
S khng chng li vi sinh vt trong c th ban u l nhng phn ng ca h
thng min dch bm sinh. H min dch bm sinh (cn gi l min dch t nhin)
bao gm cc c ch khng tn ti trong c th khi cha c nhim trng v sn sng p
ng rt nhanh khi vi sinh vt xm nhp.
Cc thnh phn chnh ca min dch bm sinh bao gm: (1) cc hng ro vt l v
ho hc nh da, nim mc, cc cht khng khun c tit ra trn cc b mt ny; (2)
cc t bo thc bo (t bo trung tnh, i thc bo) v t bo NK (t bo git t
nhin); (3) cc protein trong mu, bao gm cc thnh phn ca h thng b th v
cc cht trung gian khc ca phn ng vim; v (4) cc protein gi l cytokin
c vai tr iu ho v phi hp cc hot ng ca t bo trong h min dch bm sinh.
H min dch bm sinh to ra nhng phn ng u tin chng li s xm nhp ca vi
sinh vt.
Ngc vi h min dch bm sinh, c nhng p ng min dch khc c kch thch bi
s tip xc vi vi sinh vt v to ra cng tng dn nu s tip xc ny c lp i lp
li. Bi v dng p ng ny ch xut hin sau khi vi sinh vt xm nhp c th nn n
c gi l min dch thu c.
Tnh cht c bit ca p ng min dch thu c l tnh c hiu i vi tng phn t v
kh nng nh khi phn t xm nhp tr li c th to ra mt p ng mnh hn nhiu so
vi ln xm nhp u tin. H min dch thu c c kh nng nhn din v phn ng li vi
nhiu vt l c bn cht nhim trng hoc khng nhim trng.
Ngoi ra, n cn c kh nng tuyt vi trong vic phn bit s khc nhau rt
nh gia cc vt l ny v v vy m n cn c gi l min dch c hiu. Cc thnh phn
ca min dch thu c l t bo lymph v cc sn phm ca chng. Nhng cht l to ra
p ng min dch c hiu hoc chu tc ng ca h min dch ny c gi l khng
nguyn.
3. c im h thng min dch ca b
C th tr s sinh v tr nh min dch c nh h thng khng th nhn c t khi
cn trong bo thai, trong ba thng cui ca thai k, cc khng th t m c
truyn sang con qua nhau thai, cc khng th ny c tc dng bo v b tm thi,
c gi l min dch th ng.
Tuy nhin, cc khng th t m truyn sang con ny ch tn ti trong vi
thng u sau sinh v gim nhanh chng sau . B m l cch tt nht truyn khng
th t m qua con, gip thay th lng khng th gim. Cc cht dinh dng v khng
th trong sa m s gip duy tr min dch th ng tr lu hn.
Giai on tr ngng b sa m v bt u n dm cc khng th tr nhn c t m s suy
gim nhanh chng theo thi gian, h min dch tr cha pht trin y nn tr d b
mc cc bnh do vi khun, virut tn cng.
H thng min dich trong c th b hnh thnh nhng cha hon thin, nm rai
rac trong ngi cua be, t vung hu hong, xung tuyn c, ti lach, ng rut
va h thng bach huyt rng khp, ong vai tro nh nhng cng thanh m ngay
canh gac, ngn chn s xm nhp cua cac vi sinh vt gy bnh. Do con non
nt, cha c tip xuc vi tac nhn gy bnh nhiu, nn hiu qua cua h thng
canh gac nay con rt han ch.
4. Ti sao cn tng cng min dch h hp cho tr
Lng khng th nhn c t m gim, h thng min dch ca tr cha hon thin nn
rt d mc bnh do s tn cng ca vi sinh vt trong mi trng. Trong khng kh,
t l cc vi khun gy hi rt ln nn h h hp l c quan d b mc bnh nht tr nh.
V vy tng cng sc khng cho tr phng bnh l ht sc cn thit.
