Cau 18: trinh bay thanh phan, tac dung cua dich vi hon hop va UDLS

Da day bai tiet khoang 3 - 4l dich vi moi ngay. dich vi co [HCl] cao ( khoang 150ml/l, pH xap xi = 1) va chua pepsin, lipase, yeu to noi, chat nhay

- hau het dich vi do cac tuyen sinh acid nam o nmac vung than va day da day bai tiet

*) bai tiet acid HCl

HCl do TB vien bai tiet. Khi bi kick thick, TB vien bai tiet 1 dung dich chua khoang 150mmol HCl/l, pH xx=1

- TB vien chua nhung kenh nho, HCl dc tao ra o mang nhung mao cua kenh, cac kenh nay do vao long ong tuyen sinh acid

- vai tro cua HCl

+) tao pH can thiet de hoat hoa pepsinogen

+) tao pH toi thuan cho pepsin hd

+) sat khuan: tieu diet cac VK co trong thuc an, nhung ng bai tiet iot HCl de bi nhiem khuan dg tieu hoa

+) pha vo lop vo boc soi co thit

+) thuy phan cellulose o thuc vat non

+) tham gia co che dong mo mon vi va tam vi

*) nhom enzym tieu hoa

- pepsin : TB chinh cua tuyen sinh acid va TB nhay cua tuyen mon vi bai tiet pepsinogen ko hd. Ngay khi pepsinogen tiep xuc voi HCl db khi chung txuc voi 1 it pepsin dc tao ra trc do cong them HCl chung dc hoat hao thanh pepsin

Pepsin hd manh nhat o pH tu 2 - 3 va bi bat hoat o pH >5

+) pepsin la 1 endopentidase co td thuy phan pr thanh proteose, pepton va polypeptid

+) pepsin cung co knang tieu hoa cellulogen, thanh phan chu yeu cua mo lket giua cac TB cua thit, chi cac soi cellulogen bi tieu hoa thi enzym tieu hoa khac moi tham dc voa thit va tieu hoa pr

+) pepsin tieu hoa khoang 10 - 20% pr thuc an

- lipase cua dich vi co cung nguon goc voi pepsinogen. Moi ngay chung ta an khoang 60 - 100g lipid. Lipid gom triglycerid(90%) cholesterol, photpholipid va 1 so it cac loai vitamin tan trong mo

+) lipase la 1 enzym yeu va chi td len nhung lipid d• nhu tg hoa nhu lipid of sua, trung

+) lipase phan giaI triglycerid thanh acid beo va diglycerid

+) pH toi thuan cua lipase tu 4 - 6. Acid beo dc giaI phong o da day se kick thik niem mac ta trang bai tiet hormon cholecystokinin. Hormon nay kthick tuy bai tiet lipase

*) yeu to noi: do tb vien bai tiet cung HCl

- yeu to noi rat can cho su hap thu sinh to B12 o hoi trang. trong benh viem da day m•n tinh, teo nmac da day, TB vien bi pha huy, BN ko chi bi thay doi toan ma con bi thieu mau ac tinh vi vitamin B12 rat can cho su chin cua HC o tuy xuong

*) Chat nhay:

Do cac TB tuyen tam vi, tuyen mon vi va TB co tuyen sinh acid bai tiet. Ngoia ra tren toan bo be mat cua nmac, o giua cac tuyen co 1 lop TB nhay gla TB nhay be mat. Cac Tb nhay be mat bai tiet nhay quanh va kiem, ko hoa tan tao thanh 1 lop gel nhay, day len tren 1 mm bao phu nmac da day

- chat nhay gom ptu glycoprotein, giau glucid, cac ptu phospholipid va acid nucleic

- mang chat nhay day va kiem bao ve niem mac da day va ta trang khoi td an mon va tieu hoa cua acid HCl va pepsin

- binh thuong su bai tiet HCl va chat nhay, pepsin tg dg nhau nen dich vi co the tieu hoa thuc an nhung lai ko the tieu hoa dc ban than da day, ta trang. khi bai tiet chat nhay giam sut, nmac da day de bi an mon -> viem loet da day

- chat nhay cung co td boi tron lam cho thuc an dc vc de dang

- chat nhay dc bai tiet khi co cac kick thick co hoc ( thuc an cham vao nmac) or kick thick hoa hoc( acetylcholin, prostaglandin). Ngc lai cortisol va aspirin uc che bai tiet nhay

*) UDLS: