Cau 9 : ap suat am trong khoan mang phoi : dinh nghia, co che hinh thanh, bien doi trong chu ky ho hap, y nghia va UDLS

DN: A's trong khoang mang phoi thap hon A's khi quyen dc goi la A's am trong khoang mang phoi . A's am trong khoang mang phoi co the do dc bang cach do truc tiep hoac do gian tiep

Co che hinh thanh ;bien doi trong chu ky ho hap :

Mo phoi co tinh dan hoi do do treo tinh chat cua cac soi dan hoi thi neu cang bi keo cang ra thi luc co lai cang lon. Phoi o thi hit vao bi cang gi•n ra do do co xu huong co ve phia ron phoi. Phoi cang gi•n no to thi luc dan hoi co ve phia ron phoi cang lon trong khi do long nguc dc coi la 1 binh kin va cung tuy co kha nang dan hoi nhung nho hon rat nhieu so voi nhu mo phoi. o thi hit vao long nguc tang kinh thich, la thanh ap sat vao thanh nguc con la tang ap sat vao phoi, do tinh chat dan hoi cua phoi la tang co xu huong tach ra khoi la thanh lam cho the tich trong khoang ao cua mang phoi tang len. Theo dinh luat vat ly: trong mot binh kin, neu nhiet do ko thay doi, ap suat trong binh se giam khi the tich cua binh tang len. Chinh vi ly do tren nen khi the tich cua khoang ao mang phoi co xu huong tang len thi A's trong khoang ao se giam xuong lam cho A's trong khoang mang phoi d• am lai cang am hon. Khi phoi cang no ra o thi hit vao thi luc dan hoi co lai cua phoi cang lon va lam cho A's cang am. Khi phoi cang thu nho lai o thi tho ra thi A's se bot am hon do luc dan hoi co lai ve phia ron phoi giam xuong, la tang giam bot luc co tach khoi la thanh va the tich o khoang ao dan tro ve trang thaI ban dau.

Ngoai ra nguoi ta con dua vao su tang truong kich thich cua long nguc o dua tre sau khi sinh, kich thuoc cua long nguc thuong tang nhanh hon phoi. Vi the khien cho thanh nguc va dI lien voi no la la thanh co xu the tach khoi may ngoai cua phoi tuc la tach khoi la tang vi la tang ap sat mat ngoai cua phoi. Mat khac ap suat khi quyen thong qua duong dan khi tac dong vao cac phe nang luon lam phoi no them va bam sat theo thanh nguc. Do tinh chat dan hoi cua mo phoi nen phoi co xu huong co nho lai ko theo do no cua thanh nguc. Su co nguoc chieu nhau( long nguc no to ra, mo phoi co nho lai) d• tao ra ap suat am trong khoang mang phoi

1 yeu to nua gop phan tao ap suat am trong khoang mang phoi la dich mang phoi dc bom lien tuc vao cac mach bach huyet

- o cuoi thi tho ra binh thuong a's am trong khoang mang phoi khoang -4mmHg

- o cuoi thi hit vao binh thg a's am trong khoang mang phoi khoang -7mmHg

- Khi hit vao het suc a's am trong khoang mang phoi co the xuong toi -30mmHg

- Khi tho ra het suc a's am trong khoang mang phoi con khoang -1mmHg

*y nghia:

AS am trong khoang mang phoi co y nghi db quan trong trong ly hoc ho hap va tuan hoan

- AS am trong khoang mang phoi lam cho phoi de dan mo ra bam sat voi thanh nguc lam cho la tag luon dinh sat vao la thanh, lam cho phoi dI theo cac cu dong cua long nguc 1 cach de dang

- AS am trong khoang mang phoi lam cho long nguc cps as thap hon cac vung khac nen mau ve tim de dang va mau len phoi de dang, lam nhe ganh cho tim phai

- AS am trong khoang mang phoi lam cho hieu suat tao doi khi dat dc cao nhat vi khi hit ko khi vao phoi nhieu nhat la luc ap suat am nhat va mau ve phoi nhieu nhat tao nen su tdoi khi tot nhat nho su tg dong thong khi va tuoi mau phoi

*UDLS:

- ap suat am tro len duong khi tran dich, tran mau, tran mu, tran khi mang phoi, khi bi vet thuong long nguc.

- thung mang phoi tu ngoai vao -> ap suat duong -> ho hap dao nguoc -> khi hit vao phoi xep lai. Nuu nang gay lac lu trung that ( tim + phoi deu rung ) -> tu vong nhanh