II. Song dien nhanh va ngan noi len tinh hinh nao khi hoat dong X Noi len lao dong tri oc bat dau.
CAC TUYEN NOI TIET
Tat ca cac dong vat co xuong song (nhu ngudi, chuot, cho, meo...) deu co he thong nhting tuyen khong co ong tiet, goi la tuyen noi tiet.
Trong co the ngudi, thudng gap vo sd tuyen nhu tuyen nude bot, tuyen vi, gan, tuy ... Chung deu co ong tiet rieng, qua do, cac dich chay vao ho tieu hoa. Day la cac tuyen ngoai tiet.
Con cac tuyen noi tiet thi khong co ong tiet, ma tiet dich true tiep vao mau. San pham cua chung goi la noi tiet to hay hormon. Noi tiet to tuan hoan trong mau, chi can mot luong nho cung du anh huong toi su chuyen hoa, anh huong den sinh ly, sinh hoa, su tao hinh va su Ion cua co the.
Mot so tuyen noi tiet quan trong dac biet. Neu cat tuyen thuong than cua meo hay cho, thi it hom sau, vat thi nghiem se chet. Neu khi tuyen thuong than bi thuong ton la do mot so benh man tinh, do hoa chat hay do benh lao ch in g han, se phat sinh cac roi loan chuyen hoa ro r e t : ham luong natri trong mau giam, do dam kali trong mau tang, huyet ap ha, nguoi benh chong mat siic va yeu mon, buon non va mua, niem mac mom bi tham, da ram nau. Day la benh da nau, neu khong dieu tri co the se chet. Song, thuong thucmg benh nay rat hiem.
Tuyen tuy ciing quan trong : tuy giU hai chUc phan la vua ngoai tiet vUa noi tiet. No tiet dich tieu hoa vao ruot qua duong ong, va tiet true tiep vao mau chat insulin, noi tiet to dieu hoa su chuyen hoa hydrat carbon. Nhung thuong ton tuyen tuy cung phan anh sau sac vao su chuyen hoa, dien bien sinh ly, sinh hoa cua toan bo co the. Vi thieu insulin, su dong hoa hydrat carbon kem siit, luong duong huyet tang len. Co the lanh manh dai ra ducmg bien thanh benh nhan dai duong va rat khat nude. Khi mac benh dai duong, ta tiem insulin vao co the, cac trieu chiing tren deu giam va het.
Su roi loan hoat dong cua cac tuyen noi tiet khac nhtr tuyen giap trang, tuyen sinh due : deu gay roi loan chuyen hoa nghiem trong.
Dan them mot thi du khac :
Trong cothe ngudi co vai doi tuyen nho nhu la tuyen can giap trang ch in g han, co nhung trudng hup tuyen ay u to, tang cudng tiet noi tiet to vao mau. Noi tiet to ay qua thUa, gay can benh nang. Cac bo phan rieng khac thoai hoa, xuomg bi mat canxi nen de gay, dac biet d dui, vai, xuomg sudm va ca xuomg song. Nhieu roi loan bien di bo xuomg, lam cho benh nhan n im liet. Chi dung phau thuat cat bo cho tuyen can giap trang u thi mdi cuu duoc ngudi benh.
lQii mot trong nhting tuyen noi tiet hoat dong roi loan, co the con ngudi mac du co tap luyen, van dong den dau hay tang cudng thanh phan dinh dudng den dau thi cung kho tranh duoc mac nhting benh hiem ngheo.
He thong noi tiet vo cung phtic tap, co che cua no duoc dieu hoa mot cach tinh te va chinh xac, no duoc he than kinh kiem tra va hieu chinh, neu khi mot mAt xich ciia no bi thuong ton, thi lap ttic trong co the he than kinh dieu chinh noi khac den bu.
Noi den chtic phan dieu hoa sinh hoa, hoa hoc cua su song, ta thay no luon luon di doi vdi benh tat, bdi vi m6i su bat thudng deu cho ta thay ro horn y nghia ciia noi tiet to doi vdi stic khoe , cung nhu cac chat hoat dong khac trong co the.
Trinh bay tat ca ve tuyen noi tiet va ve vai tro cua no trong ca the, chung ta can phai noi het ve su chuyen hoa va qua trinh dien bien sinh ly hoa, hoa hoc khi yen tinh va khi lao dong, van dong. Chinh trong co the vi khong mot hinh thuc chuyen hoa nao lai khong co cac tuyen noi tiet va noi tiet to tham gia. Cac thi nghiem tren sinh vat giup chung ta hieu ro vai tro cua noi tiet to va md dudng sii dung chung de tac hop su sinh trudng va qua trinh tao lap van dong, phat trien cua ngudi.