II. Tim vai van dong
HO HAP VOI VAN DONG
Chung ta da biet chiic nang cua bo may ho hap gom co cac bo phan : mui, thanh quan, hau, khi quan, phoi, phe quan, phe nang va mang phoi. Khong khi khi ta hit vao qua mui va hoc mui di qua hong, qua thanh quan va khi quan, qua cac phe quan (cac phe quan miiOng tuong nhu canh cay to co nhieu nhanh nho bam va tiep do co nhieu nhanh nho hon niia bam theo) cuoi cung thanh nhiing ong phe quan cvic nho voi dudng kinh chua bang
t x
1/2 milimet. O dau tan cung cua cac phe quan nho co nhung chum nho goi la phe nang. Thanh phe nang va thanh mao mach nho cuc ky mong, nho mong den noi khong can trd su luu thong cua cac khi va chUc nang chinh cua su trao doi cac chat khi gitia khong khi va mau la phe nang. Phe nang co rat nhieu tdi gan 300 trieu, neu trai tren mot mat b in g , phe nang co di<?n tich tuong Ung tren dudi 70m2. Va chinh tren dien tich nay luon luon d iin ra
hien tuong mau hap thu oxy de dua di khap co the va qua trinh chuyen hoa thai khi carbonic can ba cua ca the.
Bo may ho hap con co cac chuc nang phat ra am thanh khi con ngudi muon noi, muon h a t , ... nhd co khong khi di qua thanh mon luc md, luc khep co luc cang tao nen mot am dieu nhu hat, noi, ho, ...
Nhiem vu ca ban cua van dong ho hap la phat trien ho hap va phat trien kha nang dieu hoa dong tac ho hap mot cach y thuc. Ngoai ra, muc dich cua van dong ho hap con lam cho su van dong ho hap thich Ung vdi dong tac, lao dong ky thuat de sdm chuyen no tii trang thai ho hap binh thudng hoa hop vdi trang thai ho hap van dong.
Neu dieu khien bo may ho hap tot thi tac dung ho hap
se trd nen thich Ung vdi tinh chat h o at d o n g c ua b3p thit,
tu do se t u dong n a y sinh ra moi lien he co dieu kien trong he t ho ng t r u n g u o ng t h a n kinh.
Co nhieu ngudi van dong ho hap bang mieng, nhat la nhieu nguoi tre, khi thd cang de mac nhu vay. Do do khi nang cao mure hoat dong cang thang cua bap thit. thuong thay xay ra tinh trang ho hap bang mieng d van dong vien tre. Dong thdi hien tuong do thay nhieu d mot so ngudi mdi luyen tap, miic do con it, chua duoc thich nghi, vua mdi bat dau lam dong tac la ho hit bang mieng. ho tudng hit nhu the cho do met. Hien tuong nay thuong thay d nhieu ngudi chua nam bat nguyen ly va phucrng phap thd, d nhiing ngudi lao dong cang thang bUc xuc
cung co the xay ra hien tuong do... Binh thuong thi ho hap bang mieng khong nhung khong do met ma nguoc lai con met them, co the dan tdi nhung hien tuong khong tot, tham chi con lam cho phoi bj cang dot ngot. Nha sinh ly hoc Durigeur, thOi con tre, ong da vuot qua nui Apech trong 22 gio dong ho, trong hanh trinh do da hai lan phai vuot hai ngon nui cao 1.700 met, nhung luc do chua dieu khien duoc viec thd bang mui. Ket qua kiem tra la c lam cho tinh trang phoi cang dot ngot, hoanh cach mo bi sa xuong, co the mat can bang, trong nguOi cam thay bun run, non nao kho chiu, muon dung hoat dong, phai nghi va hoat dong yen tinh, may horn sau mdi giam. Khi biet duoc nhu the, ong tap thd hit bang mui. Hai muoi nam sau, ong lai leo nui cao 5.500 met, duOng truOng 63 cay so, leo mat 26 gid, vay ma phoi va tim van khong co gi dot bien. Muc dich cua chuyen leo nui, ong muon thuc hien tinh chat tac dung ciia phuong phap ho hap : hit dai hoi biing mui, ngiing mot lat roi lai thd manh ra b in g mom.
Ngoai ra, ho hap (hit) b&ng mui con lam cho nhiing ngudi lao dong nang, van dong vien tap luyen trong mua dong hay van dong vien truot tuyet khong bi m i c benh viem lanh, lam cho cac van dong vien tranh duoc benh viem khi quan. Ngudi ho hap b in g mieng thi mang thd khong khoe,hoat dong yeu, nguc nd khong tot. Nhiing dieu neu ra tren day da chung to tinh uu viet cua viec thd b&ng mui. Khi mdi tap thd, hit bfing mui la dieu kho vi phai
khac phuc. Viec theo doi tac dung ho hap cua 90 van dong vien chay dudng trudng 30 cay so cua nha nghien cuu N.N Londanops da cho hay. Nhung ngudi hit bang mui, thd ra b i n g mom (ke rang) deu da vuot len hang dau, con nhung ngudi hit thd b in g mieng thi deu chay kem hon. Ho hap qua ke moi mim (cua mom) se tranh dupe tinh trang thd nong va tranh dupe hien tupng cach mo bi dang len.
Cac cong trinh nghien cuu trong nhieu nam qua da cho ta thay tam quan trong cua dudng ho hap trong viec dieu tiet nhip thd va chieu sau cua thd hit. Diem nay chung ta se dupe noi ro d muc nghien cuu ve cue diem.
Yeu cau co ban cua mon ho hap d nhting ngiitii lao dong nang, tuoi gia, lam viec doc hai, va khi thi dau the thao phai lam sao chuyen tu the nong sang the sau. cham va tu tu. Neu ket hop duoc dung tac dung ciia ho hap vdi ket cau dong tac thi ta se de dang dat dupe ky thuat ho hap deu va sau trong cac hoat dong lao dong va the thao. Thi du : Trong dong tac van dong vien chay trudc khi xuat phat bao gid cung thu minh lai, n g u n g vthd giay lat va dong tac cui nguOi de bat chay se giup ta thd ra rat manh.
Ky thuat ho hap da hinh thanh theo kieu phan xa co dieu kien. Su suy nghi cua cac nguOi lao dong tay chan va cac van dong vien bao gid cung tap trung vao cac dong tac cua hai tay, hai chan va the la dong thdi cung la luc tu dong luon ca ho hap deu va sau.
Dong tac ciia hai tay, hai chan song song voi siic bat va hoat dong cua long nguc, cach mo, da trd thanh vat kich thich co dieu kien cho bo may ho hap va cuoi cung trd thanh phan xa ho hap co dieu kien cua co the. nhu vay la tac dung ho hap da tu dong hoa chuyen no trd thanh bo phan trong ky sao dong tac chung. Khi thuc hien cac dong tac ky thuat va dong tac nang cung co qua trinh ho hap nhu vay. Trang thai tu dong ho hap do cung co the bi pha vd trong nhiing trudng hop hoat dong cua bap thit cang th in g keo dai qua met, qua ngudng nghia la ho hap sau lai bien thanh ho hap mau va nong. Trong thuc te, tam quan trong ciia tac dung dieu tiet ho hap (hit thd) mot cach co y thuc, thi lai co the ho hap mot cach deu va sau duoc.
Khi luyen ho hap, phai chii y tdi su phat trien ciia b i p thit long nguc va cung phai chu y ca tdi su phat trien cua cach mo nua. Moi lien he chinh xac giUa bap thit long nguc va cach mo trong khi hoat dong la nhan to chu yeu de dam bao tac dung thay doi hoi thd deu, sau trong phoi. Khi do, sue lam viec cua cach mo tang len va tang ca sue chong cu ciia no ddi vdi b i p thit bung muon de no vao long nguc (vi khi ta thd luc hit vao bung phong len, khi thd ra bung xep xuong). Su phat trien cua co bung co lien quan vdi su phat trien cua cac co long nguc va cach mo. Vi vay, khi luyen tap thd hop ly va siia doi duoc loi ho hap b i n g bung, vUa sura doi duoc loi ho hap b i n g nguc.
Ngoai ra, bien doi co nang cua bap thit bung se co loi cho trang thai sinh ly cua bo may noi tang, lam cho no khoi bi sa sut cudng do van dong cua toan bo to chuc trong khoang bung.
Qua trinh luyen tap “hit vao, ngung khoanh khac tting giay, roi tti tti thd ra” da gay duoc anh huong doi voi viec co dinh kha nang cua nguc d trang thai hit vao. Khi do, hoi tho ra la do thanh mon (cua ho hap) tti tti md. Vi vay, do anh hudng bdi stic dan hoi cua long nguc, phoi lai bi ep, cong them stic day cua hoi thd ra nen ngiic cang bi ep manh hon. Dieu do chi dat duoc khi ta tap luyen van dong mot cach co he thong deu va lien tuc.
De tting budc dieu khien duoc tron ven su hoat dong cua bo ho hap, chung ta can phai biet cach chu dong cho phep bap thit nay hay bap thit kia trong nhom bap thit ho hap chu yeu do hoat dong, hoac khong cho phep no hoat dong. Dong thOi phai chu y tdi trang thai bap thit ciia than the va chan tay. Trang thai cua nhting bap thit nay khong nhting la trd luc can de k h ic phuc khi ho hap, ma con la sue chi phoi than kinh cua toan co b a p doi khang lam diem tua ngan can chieu huOng phan xa cam giac cua bap thit de phat sinh thay doi tinh chat cua nhip dieu nhu ho hap (bien hit vao thanh thd ra hoac nguoc la i).
Neu ho hap nong chinh la ket qua dao dong cua than kinh cam giac khi bap thit ho hap chi co den ntia nguon da ngung lai. Nhu vay hit vao chi den ntia chting da thoi
va thd ra luon. Sau khi da tap thof, ta se biet cach dieu khien bo may ho hap, chi khi nao bap thit ho hap hit vao da co het r6i mdi thd ra va ket hop van dong md cang them long nguc.
Mon ho hap van dong giup cho bap thit ho hap phat trien duoc deu dan. Song song vdi su phat trien do, sue cang ciia long nguc cung tang len. Khi hit vao nguc se cang manh va khi thd ra thi nguc se hop lai rat nhieu. Hien tuong nay the hien ro ret d y thuc luyen tap ciia van dong vien.
Nhu van dong bai vi ho phai thd cang long nguc trong dieu kien d dudi nude kha nhieu trd luc. Dac biet trong moi mon the thao, sure manh ciia b ip thit ho hap la mot yeu to it nhieu co tam quan trong den viec kh&c phuc trd luc de thd.
Mon ho hap van dong con anh hudng tdi hinh dang ciia long nguc va sue co dan ciia phoi, song neu luc nao ta cam thay co su tang sue co dan cua phoi mdi la co ket qua thi khong dung. Rat nhieu van dong vien trong qua trinh luyen tap va nhUng ngudi lao dong nang sue co dan phoi ciia ho khong hon nhting ngudi khoe manh chua qua tap luyen bao gid. Cho nen van de khong phai chi muc dich de tang stic co dan ciia phoi ma chinh la cac van dong vien da loi dung duoc no mot cach that tot hay chua.
Tat ca moi ngudi lao dong chan tay nang va van dong vien can ren luyen the luc tdi mtic do thich dang roi mdi
tap ho hap. Khong co su hoat dong cua bap thit toan than ma da van dong ho hap thi se co the dan ten hang loat nhiing hien tuong khong thuan loi cho khi van dung ho hap vao van dong lao dong va tap luyen the thao. Chat bot trong phoi la do so ket tu cua tinh dan hoi phoi va mang phoi ma co. Khi ho hap sau co the bi cang duoi rat manh. Dieu do la co so de giai thich hien tuong tai sao co nhung ngudi mdi lao dong, van dong vien moi tap co nguOi m i c benh truong phoi dot ngot, nhat thoi khi anh ta tien hanh nhung hoat dong cang thang keo dai. Ho hap khong dung va co sure qua nhieu cung se dan tdi tinh trang nhu vay.
Cac van dong luyen tap ho hap ma khong g i n lien vdi van dong bap thit thi vo bo vi van dong ho hap ma khong song song vdi nhung hoat dong ve the luc thich dang thi he so tan dung phan oxy trong khong khi hit vao phoi se thap hon.
Hoat dong bap thit chinh la cach de dieu tiet tac dung thay doi hoi thd, no tao dieu kien cho viec tan dung oxy trong khong khi hit vao phoi duoc tot hon
Nhung tinh hinh noi dung tren day da chung minh mot quan diem, neu khong van dong bap thit de co yeu cau ve oxy thi tang cuOng dong tac ho hap la viec lam khong hop ly, chua thich dang ciia tat ca nhiing nguch luyen tap ho hap de hoat dong bang sue luc.