- DQngkinh Benh glaucom.
THU6c TAc DVNG TREN HE THAN KINH THlIC vAT
HE THAN KINH THlIC vAT. ..
1.D~ CU'dNG
H~ than kinh thuc vat con goi 130h~ than kinh tu d('mg,chuyen dieu khien cac hoat d('mgngoai y muon cua con nguoi. No giu vai tro dieu hoa chuc phan cua nhieu co quan quan trong nhu ho hap, tuan hoan, tieu hoa, than nhiet, chuyen hoa va bai tie't...Vi the', h~ than kinh thuc vat 130h~ dieu hoa cac hoat d9ng co tinh chat song con cua co th~, giup co th~ song 6n dinh va thich nghi duoc vdi nhirng thay d6i cua moi truong.
SQithan kinh thuc vat biit nguon tu cac trung tam dnao va tuy song, di tdi cac co quan, cac tang, mach mau. H~ than kinh thuc vat duoc chia thanh 2 he: h~ giao cam (sympathetic) va h~ pho giao cam (parasympathetic). Hai h~ nay co chuc nang d6i nguQcnhau trong dieu hoa cac ho~t d9ng cua cd th~.
1.1.D~cdi~m giai phau
1.1.1.Trung tam eua h~ thtin kinh th¥e vg,t
• Trung tam eua h~ giao cam
Nilm d chat xam sung ben cua tuy s6ng, tu d6t s6ng c6 VII toi d6t s6ng thiit lung III. Tu day, cac sQithftn kinh giao cam di tOi khiip cac cd quan trong cd th~, dieu hoa ho~t d9ng cua cac cd quan nay.
• Trung tam eua h~ph6 giao eam
Nam d nao giira, hanh nao va tuy cling.
Tu nao giua, hanh nao: cac day than kinh ph6 giao cam (di kern voi day than kinh SQnao) chi ph5i hoat dQngcua cac co quan vung dau, nguc va a bung: day than kinh so'III chi phdi hoat dQngcua mat (co co d6ng ti'i, co th~ mi). Day than kinh so'VII chi phdi hoat dQng cua cac tuyen dudi ham, tuyen nude bot, tuyen I~,tuyen mui. Day than kinh so' IX chi phci hoat dQngcua tuyen mang tai. Day than kinh so' X chi phdi hoat dQng cua cac co quan d nguc va a bung (tim, phdi, thuc quan, da day, toan bQruot non, nua dfiu ruot gia, gan, tui mat, t\1Yva phan tren cua nieu quan).
Tu tuy cling: cac soi ph6 giao cam chi ph5i ho~t dQngcua caccd quan trong h5 ch~u nhu bang quang, phfin thap cua ni~u quan, d~i trang xu5ng, tr\1c trang va cd quan sinh d\1cngoai.
N6i chung, caccd quan d~u chiu s\1 chi ph5i cua ca 2 h~ giao cam va ph6 giao cam (Xem hinh 4.1).
1.1.2. Cae Sl/i va synap th6n kinh th¥e vij,t
Cac sQithfin kinh th\1Cv~t (sQithfin kinh di tii trung tam Wicd quan dap ling) thudng dUQccau t~o bdi 2 neuron. Neuron tii trung tam den h:;tchgQiIa sQi trudc h~ch, neuron tii h~ch Wicd quan dap ling gQiIa sQisau h~ch.
D5i vdi h~ giao cam: sQitrudc h:;tchngtln, con sQisau h~ch dai (do cac h~ch giao cam n&mgfin trung tam ngay c~nh cQts5ng).
D5i vdi h~ ph6 giao cam: sQitrudc h~ch dai con sQisau h~ch ngtln (do cac h~ch ph6 giao cam n&m gfincd quan dap ling, th~m chi n&m ngay tren thanh cua cd quan dap ling).
Synap cua h~ thfin kinh th\1c v~t Ia nhung khdp n5i giua hai neuron ho:1\.c giua neuron vdicd quan dap ling (g6m mang trudc, mang sau va khe synap). C6 2 Io~i synap: synap giua sQi sau h~ch vdi cd quan dap ling va synap giua sQi trudC h:;tchvdi sQisau h~ch (hinh 4.2).
1.2. Chat dan truy~n than kinh
Chat d~n truy~n thfin kinh (chat trung gian h6a hQc)1:\ nhung chat h6a hQCd6ng vai tro trung gian d~n truy~n xung dQng thfin kinh qua khe synap. Chat d~n truy~n thfin kinh dUQctang hQp ngay t:;ti te bao thfin kinh, sau d6 dUQcd\1tru dudi d~ng phlic hQp trong cac h~t d:1\.cbi~t d ngQn sQithfin kinh d~ tranh bi phan huy. H~ thfin kinh th\1Cv~t g6m h~ giao cam va h~ ph6 giao cam. TUdngdudng vdi 2 h~ nay c6 2 lo:;tichat trung gian d~n truy~n thfin kinh chinh.
Th~n
Than kinh ph6 giao cam
ccnan hoa mong mat
covong mong mat
Tuyen mt& bot M~eh mau dau vac6
Tuyen nLldemat Tuyen nLtdebot Tim Tim £lLlong ho hap £lLtOngho hap Tuyen ma hoi Da day D~day Gan Laeh £l~1trang ngang Tuyenth~ngth~n £l~1trang True trang Ni~u qulin Th~n Bang quang
£l~1trang xuong Bang quang
Tnrc tranq
coquan
sinh dye ngoai Mach rnau chi dLtdi
C9t song
Hinh 4.1. H~thong than kinh thirc vat
Chat trung gian cua h~ giao cam la cac catecholamin (adrenalin,
noradrenalin hoac dopamin) cod ngon sci sau hach giao cam. Cac chat nay duoc
goi la catecholamin vi trong cau true deu co nhan catechol (gom vong benzen va 2 nhom -OH d vi tri ortho) va chuoi amin d nhanh ben. Chung con duoc goi la cac amin cuong giao cam. Tuy nhien, co nhieu amin cuong giao cam khong phai la catecholamin nhu phenylephrin, ephedrin, amphetamin ...
Chat trung gian cua h~ pho giao cam la acetylcholin, cod ngon sci truce hach pho giao cam, ngon sci sau hach pho giao cam va ngon soi truce hach giao cam.
Ngoai u
- Ngon sci sau hach giao cam chi ph6i hoat dQngcua tuyen m6 hoi tie't ra acetylcholin.
- Day giao cam chi ph6i hoat dQngcuatuyen tuy thuong than khong di qua hach nao, tan cling tiet ra acetylcholin, r6i kich thich tuyen tuy thuong than tie't ra adrenalin. HAuhe't adrenalin duoc bai tiet d tuy thuong than.
Vivay, nguoi ta goi tuy thuQng th~n la h~ch giao cam kh6ng 16.
- Day thAn kinh v~n dQngchi ph6i ho~t dQngcua cd van ciing khong di qua h~ch nao, t~n cling tie't ra acetylch9lin.
Hanhtuy
C9tsong
ACh ACh
N M
Day pho giao cam Co tim, co tron, te baotuyen Day giao cam Tuyen mo hoi
Day giao cam Co tim, co tron, te bao tuyen
D