- Cac qui iuit van chuyen mau trong he mach Phan xa dieu hoa tim mach.
1. Hoat dpng cua tim
-
Hoqt dpng cua GV
tu dpng.
- GV dat cau hdi din dit. + Hoat dpng tu dpng cua tim cd dugc la do ciu tao nao cua tim?
- GV ggi y:
+ Quan sat "tranh trung khu phat nhip va hp thd'ng din Uuy6n ciia tim".
+ Nghien ciiu SGK trang 73-
Hoqt dpng cua HS
- GV danh gia bd sung
kie^n thlie.
Ndi dung
- HS thue hien cac thao
tac.
+ Quan sat uanh, chii y tdi ngan tim, bo sgi...
+ Thao luan nhdm thdng nhat y kie'n.
- Dai dipn mpt vai HS trmh bay tren tranh ve ->• Ldp nhan xet.
- HS khai quat ki^n thiic.
a) Co tim cd khd ndng hoqt dpng tu dpng
Ke't luan
• Tim ed kha nang hoat ddng tu ddng la do ciu tao cua tim, chu ye'u la he dan truyen tim:
+ He dan truydn nam trong eac sgi co bop dd duy tri su CO bdp tu dpng eua tim. + He din truydn gdm: • Ndt xoang nhi nim tren thanh nhT phai.
• Nut nhi thit: nim d thanh tam nhT phai giiia la trong cua van 3 la va 15 xoang tinh mach vanh.
- Bd His: xuit phat tii hach nhT thit chia thanh hai
Hoqt dpng cua GV
- GV dan dit; ngoai hoat
dpng tu dpng tim cdn ed cae boat dpng khac.
Dd tim hieu cac hoat dpng nay, GV yeu ciu HS: + Quan sit tranh hinh. + Hoan thanh phie^u hoc tap sdi.
- GV ke phie'u hgc tap len bang dd HS chiia bai. - GV nhan xet danh gia va thong bao dap an diing va yeu cau GV rut ra ke't luan va GV ghi muc b.
Hoat dpng cua HS
'
- HS boat dpng nhdm.
+ Ca nhan thu nhan ki^n thiic tir tranh hinh, SGK muc a,c trang 75, kie'n thiic sinh hgc 8.
+ Trao ddi de thdng nhit y kien vi ghi phieu hgc tap. - Dai dien nhdm ghi dap an phie'u hgc tap len bang. - Ldp cilng thao luan.
Npi dung
nhinh di den cae co cua 2 tam thit. Mdi nhanh lai phan chia tao thanh mang ludi Pud'c~km.
* Hoat ddng tu dpng ciia tim.
- Nut xoang nhi tu phat nhip, xung dugc truydn tdi 2 tam nhi, tdi niit nhi thit, truydn theo bd His tdi mang Pud'c-kin tdi tam thit lam tam thit co.
b) Hoqt ddng theo qui luat vd chu ki cua tim
Dap an phieu hgc tap so 1 T I M HIEU HOAT DONG C D A T I M
* Dac diem hoat dpng
Cd tim + Hoat dpng tU dpng khdng theo y mudn Cd XUdng + Theo y mudn 191
- Tfnh quy luat - Tfnh chu ki + C6 + C6 + Khdng + Khdng, hoat ddng khi cd kich thfch
Hoqt ddng cua GV Hoqt dpng cua HS Npi dung - GV neu eau hoi.
+ Hoat dpng ed qui luM va theo chu ki cua tim the
hipn nhu thi nao?
+ Hoat dpng cua ctJ tim khac boat dpng co xuong nhu the' nao?
+ Vi sao tim hoat dpng sudt ddi ma khdng mpt mdi?
- GV bd sung kie'n thu'c: + Hoat dpng eua tim ed tCnh quy luat va chu ki la do cau tao ciia tim dac biet, CO tim chi co bdp don ma khOng CO Cling (Tiic la khong cd hien tugng chudt rdt d CO tim nhu co tay, co chan...).
- HS van dung cac k i ^ thiic d phie'u hgc tap vi
SGK trinh bay. K^t lu|n:
- Co tim hoat ddng theo qui luat "tat ca hoac khdng CO gi"
+ Kich thich vdi cudng dp dudi ngudng -> co tim khdng CO bdp.
+ Kich thieh tdi ngudng -> tim CO tdi da.
+ Kich thfch tren ngudng tim khfing co manh hon. - Tim boat ddng theo chu ki. Chu ki tim gdm 3 pha: + Pha CO tam nlu. + Pha eo tam thit. + Pha gian chung.
Hoqt ddng cua GV
+ Nhip tim ling vdi chu.ki tim (70 lin phut).
- GV eho HS nhic lai thanh phin eua hp mach va vai tro ciia nd.
- GV hoi: mau chay Uong he mach dugc la do ye'u td nao?
Hoqt dpng cua HS
- GV dan dit: boat dpng
cua he mach lien quan dg^n huyet ap, van tdc mau. - GV yeu ciu tim hieu ve huyet ap bang cau hdi:
+ Huydt ip la gi? do dau
micd?
+ Huy^t ap thay ddi nhu the' nao Uong he mach? Su thay ddi dd do dau va cd y nghia gi?
- HS neu dugc: Hp mach gdm: Dpng mach, tinh mach va mao mach.
- HS nghien ciiu SGK va ke't hgp kien thiic sinh hgc tra idi.
- Ldp theo ddi, nhan xet bd sung.
- HS nghien ciiu SGK trang 76, quan sat hinh 19.3 va tranh:"Bie'n ddi huydt ap tren vong tuin hoan", nim bit kien thiic.
- Thao luan nhdm, thdng nhat y kien.
- Yeu dn neu duoc:
Npi dung