Bai 28. DIEN THE NGHI VA DIEN THE HOAT DONG
2. Co che hinh thanh dien the nghi
Co che:
- Cd su chenh lech vt nong do Na"" va K"^ giiia dich md va dich bao (trong va ngoai mang).
* Lien he: GV giang giai:
Con ngudi da ung dung dien te bao vao nhi6u llnh virc trong cuge song.
Do dien the ciia dia phoi triing gia cam de xac dinh miic song cua ga, vit ngay tCr ngay dau phat trien ciia ph6i. Tren co so dd chgn triing td't tiep tuc cho a'p nd, loai bd triing xau.
+ Nong do K"* trong dich bao Ion hon ngoai dich md.
+ Nong do Na"" trong dich md Idn hon dich bao.
- K"" cd xu hudng di chuyen ra ngoai mang.
- Na* cd xu hudng di chuyen vao trong mang thuan gradian ndng do.
- Trang thai nghi mang CO tinh tha'm chgn Ige ddi vdiK*
+ Kenh K* md -^ K" di ra kenh Na"" ddng.
- K"" di ra mang dien duong (+) bi anion (-) giii lai nen khdng di ra xa khdi mang.
- Bom Na" / K"' thudng xuyen chuyen Na' ra va K"^ vao nen duy tri dugc tinh dn dinh tuong ddi ciia dien the nghi.
Hoqt dong 2. TIM HIEU DIEN THE HOAT D O N G
Muc tieu:
- HS trinh bay dugc khai niem dien the boat ddng, co che hinh thanh dien thd' boat dong.
- HS biet lien he thuc ti6n.
Hoqt dong ciia GV - GV treo tranh hinh dd thi dien the boat dong va yeu cau HS:
+ Quan sat d6 thi
+ Tra Idi cau hdi: The nao la dien the boat dong?
- GV nhan xet, danh gia va giiip HS hoan thien kien thiic.
Hoqt dong cua HS
- HS boat dong dgc lap vdi SGK va hinh ve.
- Yeu cau chi ra dugc:
+ Khi cd kich thich tdi ngudng te bao than kinh hung pha'n.
+ Bien ddi dien the nghi thanh dien the boat dong.
- Dai dien HS trinh bay
—> Idp nhan xet, bd sung.
Noi dung 1. Khai niem
Dien the boat dong phat sinh la do su chenh lech ciia dien the giiia vung boat dong va vung yen tinh.
- VCing da hung phan mang dien tich am, cdn vung yen tinh mang dien tich duong.
- GV yeu cau HS:
+ Quan sat hinh 28.3 va dgc thdng tin SGK muc 11.1 trang 110.
+ Chii thich vao do thj 28.3 cac giai doan phan cue, dao cue, tai phan cue.
+ Tra Idi cau hdi:
Nguyen nhan nao dSn den hien tugng mat phan cue, dao cue, rdi lai tai phan cue.
- GV yeu cau:
+ Quan sat hinh 28.2 va hinh 28.3.
+ Phan tich su di chuyen ciia cac ion Na" va K* qua mang va tac dung ciia su di chuyen nay.
- GV nhan xet, danh gia va giiip HS hoan thien kien thiic.
- HS phan tich van dung kien thiic d boat dong 1 de khai quat.
Hien tugng phan cue, dao cue, tai phan cue la do mang bi thay ddi dien the giua trong va ngoai mang ciia te bao.
- HS hoat dong nhom.
+ Ca nhan nhan biet kien thiic tCr viec phan tich tranh hinh.
+ Trao ddi trong nhdm th6'ng nhai y kien.
- Yeu cau neu dugc:
+ Chenh lech ndng do Na", K'^ trong va ngoai mang liic binh thudng.
+ Khi bi kich thich do cac kenh Na"", K'" md nen ion Na*, K* di chuyen 6 at gay ma't phan cue va dao cue -ằ xuat hien dien the hoat dong.
- Dai dien nhdm trinh bay tren tranh hinh -^ lop nhan xet.
2. Co che xuat hien dien the boat dong
- GV bd sung:
+ Tit dien the nghi chuyen thanh dien the boat ddng phai bien ddi dien.
+ Khdng dung dien ke de do dien the hoat ddng vi su bien ddi dien qua Idn phai diing dung cu khac va ghi dugc dd thi hinh 28.3.
+ Cdng Na* ddng md 1/lOOOs.
* Lien he: GV thdng bao v6 ling dung ciia ddng dien sinh vat.
- San xuat thiei bi dien tu phat hien thdi ki dong due ciia bd de giao phoi.
chan doan thdi gian de ciia bd.
- Ghi dien nao do va dien tam dd de chan doan benh.
- Khi bi kich thich tinh tha'm cua mang tai dd thay ddi.
- Kenh Na" md rgng -^Na' 6 at tran qua mang vao dich bao gay mat phan cue (khii cue) rdi dao cue (ngoai mang tich dien am, trong mang tich dien duong).
- Kenh K* md va kenh Na* ddng, K* tran qua mang ra ngoai dich mo gay nen tai phan cue (ngoai mang lai tich dien duong +, trong mang lai tich dien am - ) .
- Qua trinh bien ddi dien d mang da xuat hien dien hoat ddng (xung thSn kinh).
* Luu y:
- Na* trong dich bao nhieu hon ngoai dich md.
- K* trong dich bao lai it hon ngoai dich m6.
- Can phan phoi lai Na*
va K* giiia trong va ngoai mang nhd bom Na*, K*
Hoqt dong 3. LAN TRUYEN XUNG THAN KINH TREN SOl THAN KINH Muc tieu:
HS hieu va trinh bay dugc each Ian truySn xung than kinh tren sgi than kinh cd bao mielin va khdng cd bao mielin.
Hoqt dong ciia GV
- GV hdi:
+ Xung than kinh la gi?
+ Xung than kinh Ian truySn do dau?
- GV nhan xet, danh gia va giiip HS hoan thien kien thiic.
- GV can lun y HS la: De dan truySn dugc cac xung thdn kinh tren cac sgi th^n kinh thi dieu kien bat bugc cac sgi than kinh phai toan ven ve ca'u tao va chirc nang sinh li.
- De tim hieu each Ian truyen xung than kinh tren sgi than kinh GV yeu cau.
+ Quan sat tranh hinh 28.4. 28.5 SGK.
+ Hoan thanh cac noi dung cua phieu hgc tap:
"Lan truyen xung than kinh tren sgi than kinh'
Hoqt dong ciia HS
- HS boat dong d6c lap vdi SGK de tra Idi cau hdi -> Idp nhan xet.
- HS boat dong nhdm: