I. MUCTIEU 1 Kien thurc
3. Din truyen xung than kinh trong cung
than kinh trong cung phan xa
- GV nhan xet, danh gia va giiip HS hoan thien kien thuc.
- GV bd sung kie'n thiic: + Cung phan xa cd nhieu noron tham gia thi phan ling dien ra cham.
+ Toe do dan truydn xung than kinh qua xinap bi cham lai.
- GV hdi md rgng:
+ Vi sao khi hang loat xung than kinh lan de'n xinap lam vd rat nhieu bdng, nhung khi lai cd
- Dai dien eac nhdm trinh bay -> Idp nhan xet.
- Trong 1 cung phan xa, xung than kinh di theo mdt chidu nhai dinh qua cac xinap la do:
+ Xung than kinh truyen de'n tan cung cua mdi sgi than kinh tdi chuy xinap se lam thay ddi tinh tham ddi vdi Ca**
+ Ca** tiir ngoai dich md tran vao dich d chuy xinap lam vd cac bdng giai phdng chai trung gian hoa hgc vao khe xinap.
+ Cac phan tii chai trung gian hoa hgc gan vdi cac thu the d mang sau xinap -> lam thay ddi tinh tha'm mang sau xinap, lam xuat hien xung than kinh va tie'p tuc lan truydn dgc sgi than kinh, va nhu the' cho den ca co quan dap ti-ng.
hang loat xung than kinh mdi de'n vSn thay bdng bj vd va giai phdng chat trung gian vao khe xinap? + Tai sao chat trung gian hoa hgc khdng bi li dgng lai d mang sau xinap?
* Lien he:
- Thudc tay giun san cho Ion la Dipterex sau khi Ign uong thud'c vao rugt, thuoc nga'm vao giun pha buy enzim d xinap, axetylc6lin se tieh tu nhieu d mang sau xinap gay hung pha'n lien tuc, CO cua giun san co tetanos lam giun san ciing dd khdng bam dugc vao niem mac rugt.
- Thudc Atropin phong be' mang sau xinap lam mat kha nang nhan cam eia mang sau xinap, lam giam CO that nen cd tac dung giam dau.
- HS thao luan van dung kie'n thiic.
- Yeu cau neu dugc: + Mang sau cd cac enzim phan buy axetylcdlin thanh axetat va cdlin.
+ 2 ehai nay quay lai mang trudc vao chuy xinap va da dugc tai tdng hgp lai thanh axetylcdlin, chiia trong cac bdng xinap.
Hoqt dong 2. TIM HIEU MA THONG TIN THAN KINH
Muc tieu:
- HS hieu khai niem ma th6ng tin thdn kinh. - HS biei duoc cac kieu ma hoa than kinh.
Hoqt dong cua GV - GV yeu cau HS trinh
bay each xii li du lieu d may vi tinh de hudng suy nghi cua HS vao bai hgc. - GV hdi: Hang ngay chiing ta thu nhan dugc nhiing thdng tin gi tir cupc song?
- GV dat van de:
+ Cac th6ng tin tii' co quan thu cam dugc truydn vd dau? va dugc xii li nhu the' nao?
- GV nhan xet, giiip HS hoan thien kie'n thire.
Hoqt dong cua HS
- HS cd the tra Idi:
+ Con ngudi nhin tha'y mau sac cua vat, hinh khdi cua vat.
+ Con ngudi nghe dugc nhieu loai am thanh khac nhau, cam nhan dugc mui vi ciia thiic an.
- HS van dung kie'n thire sinh hgc Idp 8 tra Idi dugc:
+ Thdng tin dugc truyen ve cac vung khac nhau ciia vd nao.
+ Thdng tin dugc ma hoa va giai ma tuong tu nhu hoat ddng cua may vi tinh.
- Dai dien HS tra Idi -^
Idp nhan xet, bd sung.
Noi dung
* Khdi niem md thong tin
- Thdng tin tCt cac thu
quan khac nhau gui vd trung uong dudi dang cac
- GV neu va'n dd:
Ngudi va ddng vat nhan biei dugc cac kich thich khac nhau nhu the' nao? - GV ggi y: Cac thdng tin dugc phan chia thanh 2 loai: Thdng tin cd tinh chai dinh tinh va thdng tin cd tinh chai dinh lugng.
- GV nhan xet, danh gia va sii dung cac thdng tin bd sung d sach GV de giang giai.
- HS van dung kie'n thiie sinh hgc 8 tra Idi:
+ Kich thich am thanh dugc truyen theo day than kinh thinh giac ve vung thinh giac.
+ Kich thich' anh sang, mau sac, -liinh dang cua vat dugc truydn theo day than kinh thi giac vd vung thi giac d nao.
+ Kich thich: vd mui vi theo day than kinh khiiu giac vd vung khiiu giac d nao.
- Cac kich thich dugc phan tich d eac vung va cho biei dugc dac diem ciia cac kich thich.
- HS trinh bay -^ Idp
nhan xet, bd sung.
xung than kinh da dugc ma boa (ggi la ma thdng tin) va trung uong than kinh se giai ma de nhan biei thdng tin mot each chinh xac.