Cau 3 : trinh bay co che TK dieu hoa hd tim va UDLS

TK thuc vat : giao cam va pho giao cam

- he TK pho giao cam: trung tom TK pho giao cam dieu hoa hoat dong tim nam o hanh n•o, do la nhan cua day X. cac soi truoc hach cua day X dI toi hach pho Giao cam chi phoi hd cua nut xoang va nut nhi that

+) thi nghiem: cat day Tk X o daon co cua cho, dung dong dien kthick vao dau ngoai bien cua day X thay, neu kick thick voi cuong do vua phaI lam tim dap cham va yeu. Nuu tang cuong do kick thick thi tim ngung dap nhung neu cu kick thick tiep tuc thi tim lai dap tro lai, do la hien tg thoat uc che. Tim thoat uc che la do bo his phat xung dong, vi bo his ko chiu su chi phoi cua day X or do tim ngung dap mau ve tam nhi nhieu hon lam ap suat mau trong tam nhi tang len, kick thick nut xoang phat xung dongtro lai

Nhu vay, td cua day X doi voi hd cua tim:

(+) giam tan so tim

(+) giam luc co bop tim

(+) giam toc do dan truyen xung dong trong tim

(+) giam tinh hung phan cua co tim

He TK pho giao cam td len tim thong qua hoa chat trung gian la acetyl cholin

- he TK giao cam: Tk giao cam dieu hoa hoat dong tim nam o sung ben chat xam tuy song doan lung 1-3, tu day cac soi TK dI den hach giao cam nam gan cot song. Cung co 1 so soi xphat tu sung ben chat xamtuy song doan co 1-7 dI den hach giao cam den tim gay tac dung ngc voi td cua day X tang(nhip, luc, truong luc, hung phan, dan truyen)

Hei TK giao cam td len hd cau tim thong qua hoa chat trung gian noradrenalin

*) cac phan xa dhoa hdong cua tim

- binh thuong co:

+) 1 phan xa giam ap luc mau tang o quai DM C or xoang Dm canh, td vao cac receptor nhan cam as o day, lam xh cac xung dong cahy theo day TK hering ve hanh n•o, kick thick day X lam tim dap cham va yeu-> giam HA

+) 2 pxa lam tang nhip tim: khi Cm O2 trong mau giam, [CO2] tang or HA giam, tac dong len receptor o than DM canh va DMC, lam xh xung dong dI theo day TK Hering ve hanh n•o, uc che day X, lam cho tim dap nhanh.

+) 3 px tim- tim: px khi tim u mau khi mau ve tim nhieu no lam cang gi•n tam nhi dbiet tam nhi phai. xung dong truyen ve hanh n•o qua cac soi cam giac cua day X -> uc che day X -> tim dap nhanh manh thanh toan tinh trang u mau.

- phan xa bat thg:

+) 4 px mat tim: no phat sinh khi ep lien tuc ve nh•n cau se kick thick dau mut day X, tao xung dong theo daay V ve hanh n•o -> khick thick day X -> tim dap cham

+) 2 px goltz: khi dam manh vao vung nguc, thuong vi or co keo cac tang o o bung khi phau thuat , xung dong dI theo dg cam giac or TK tang len hanh n•o, dg truyen ra gay hung phan day X -> co the tim ngung dap

+) 3 phan xa hau mon - mat : khi kick thick vao vung hau mon va tang sinh mon manh truyen vao theo day TK tang truyen ra -> kick thick day X -> tim ngung dap

*) anh huong cua vo n•o va 1 so trung tam TK #:

- hd cua vo n•o: cac cam xuc manh nhu hoi hop, so h•I lam bien doi nhip tim, khi hoi hop tim dap nhanh, khi so h•I or qua xuc dong nhip tim co the tang len nhung cung co khi tim dap cham, tham chi ngung dap

- trung tam ho hap anh huong den trung tam day X owr hanh n•o uc che trung tam day X, tim dap nhanh hon 1 chut. Khi tho ra trung tam day X thaot uc che lam tim dap cham lai 1 chut

- trung tam nuot o hanh n•o anh huong den trung tam day X: khi nuot, ttam nuot uc che trung tam day X, lam tim daapj nhanh hon 1 chut

*) UDLS