Lub pov haum cov khaubncaws sab nraud povtseg yog lub ntsiab lus tseem ceeb hauv embryology. Lawv xaiv cov khaubncaws sab nraud povtseg ntawm lub cev ntawm tus menyuam hauv plab thaum ntxov ntawm nws txoj kev loj hlob embryonic. Feem ntau, cov khaubncaws sab nraud povtseg yog epithelial nyob rau hauv cov xwm.
Lub pov haum txheej feem ntau muab faib ua peb hom:
• ectoderm - daim ntawv sab nrauv, uas tseem hu ua epiblast lossis txheej txheej tawv nqaij;
• Endoderm - txheej txheej hauv hlwb. Nws kuj tseem hu ua hypoblast lossis entero-glandular;
• txheej nruab nrab (mesoderm lossis mesoblast).
Cov nplooj ntawv Germinal (nyob ntawm lawv qhov chaw, lawv muaj cov yam ntxwv ntawm tes. Yog li, txheej txheej ntawm lub embryo muaj lub teeb thiab siab hlwb, uas zoo sib xws hauv cov qauv rau cylindrical epithelium. Cov nplooj sab hauv muaj nyob hauv. Feem ntau ntawm cov hlwb loj, uas tau ntim nrog cov yolk lamellae tshwj xeeb thiab muaj lub ntsej muag flattened uas ua rau lawv zoo li squamous epithelium.
Mesoderm ntawm thawj theem muaj cov spindle thiab stellate hlwb. Tom qab ntawd lawv tsim cov txheej txheem epithelial. Needless hais, ntau tus kws tshawb fawb ntseeg tiasmesoderm yog cov txheej hauv nruab nrab cov kab mob, uas tsis yog txheej txheej ntawm cov hlwb.
Cov kab mob khaubncaws sab nraud povtseg thaum xub thawj muaj qhov tshwm sim ntawm lub hollow tsim, uas yog hu ua blastodermal vesicle. Ntawm ib qho ntawm nws cov ncej, ib pawg ntawm cov hlwb sib sau ua ke, uas yog hu ua cell mass. Nws ua rau lub plab thawj (endoderm).
Nws yuav tsum tau hais tias cov kabmob sib txawv yog tsim los ntawm cov embryonic nplooj. Yog li, lub paj hlwb pib los ntawm ectoderm, lub plab zom mov pib los ntawm endoderm, thiab lub cev pob txha, circulatory system thiab cov leeg nqaij los ntawm mesoderm.
Nws kuj yuav tsum tau muab sau tseg tias tshwj xeeb embryonic daim nyias nyias yog tsim thaum lub sij hawm embryogenesis. Lawv yog ib ntus, tsis koom nrog hauv kev tsim cov kabmob thiab muaj nyob tsuas yog thaum lub sij hawm embryonic txoj kev loj hlob. Txhua chav kawm ntawm cov kab mob muaj sia muaj qee yam hauv kev tsim thiab cov qauv ntawm cov plhaub no.
Nrog rau kev txhim kho ntawm embryology, lawv pib txiav txim siab qhov zoo sib xws ntawm embryos, uas tau piav qhia thawj zaug los ntawm K. M. Baer xyoo 1828. Ib me ntsis tom qab, Charles Darwin tau txheeb xyuas qhov laj thawj tseem ceeb rau qhov zoo sib xws ntawm embryos ntawm tag nrho cov kab mob - lawv cov keeb kwm. Severov, ntawm qhov tod tes, sib cav tias cov cim qhia ntawm embryos yog txuam nrog evolution, uas tshwm sim feem ntau los ntawm anabolism.
Thaum muab piv rau theem tseem ceeb ntawm kev loj hlob ntawm embryos ntawm cov chav kawm sib txawv thiab hom tsiaj, qee yam tau pom, uas ua rau nws muaj peev xwm tsim txoj cai ntawm embryonic zoo sib xws. Cov kev cai tseem ceeb ntawm qhov notxoj cai yog tias embryos ntawm cov kab mob ntawm tib hom nyob rau hauv thaum ntxov theem ntawm lawv txoj kev loj hlob yog heev zoo sib xws. Tom qab ntawd, lub embryo yog tus cwj pwm los ntawm ntau thiab ntau tus neeg cov yam ntxwv uas qhia tias nws koom nrog cov genus thiab hom. Nyob rau tib lub sijhawm, cov embryos ntawm cov neeg sawv cev ntawm tib hom tau sib cais los ntawm ib leeg, thiab lawv qhov zoo sib xws tsis tau taug qab lawm.
