Thaum lub sij hawm embryonic txoj kev loj hlob ntawm txhua tus tsiaj, cov txheej txheem tseem ceeb yog ua los tsim cov neeg tshiab. Ib qho kev ua tsis tiav lossis yuam kev thaum lub sijhawm no tuaj yeem ua rau muaj kev puas tsuaj loj rau cov menyuam yaus, txawm tias tus menyuam yug los tuag.
Lub embryonic txoj kev loj hlob ntawm cov ntses yog paub zoo, ua tsaug rau qhov tseeb hais tias lawv cov qe yog pob tshab thiab tag nrho cov txheej txheem yuav raug soj ntsuam los ntawm sab nraud siv cov cuab yeej xws li ib tug magnifying iav. Hauv tsab xov xwm no ntawm peb lub xaib peb yuav qhia koj qee lub tswv yim txog embryology thiab, tshwj xeeb,
Embryology Basics
Kom delve rau hauv embryonic txoj kev loj hlob ntawm ntses, peb yuav tsum xub paub ib co ntsiab lus ntawm embryology, xws li hom qe thiab cov theem uas ua rau thaum ntxov embryonic kev loj hlob..
Peb tuaj yeem pom qhov sib txawv hom qe, nyob ntawm seb cov yolk faib thiab nws muaj pes tsawg. Yuav pib nrog, peb yuav hu lub qe lub cell uas tshwm sim los ntawm lub union ntawm ib tug ovule thiab ib tug spermatozoon thiab, yolk, txheej ntawm cov khoom noj uas muaj nyob rau hauv lub qe thiab yuav ua zaub mov rau lub neej yav tom ntej embryo.
Hom qe raws li lub koom haum ntawm lub yolk sab hauv:
- Isolecytic Eggs: Lub qe yog sib npaug faib thoob plaws hauv lub qe. Ib yam ntawm cov tsiaj poriferous, cnidarians, echinoderms, nemertines thiab mammals.
- Telolecytic qe: yolk yog tsiv mus rau ib cheeb tsam ntawm lub qe, yog opposite qhov chaw uas lub embryo yuav loj hlob. Cov tsiaj feem ntau tsim los ntawm cov qe no, piv txwv li mollusks, ntses, amphibians, tsiaj reptiles, noog, thiab lwm yam.
- Centrolecyte qe: lub qe yog ncig los ntawm cytoplasm thiab qhov no, nyob rau hauv lem, ncig lub nucleus uas yuav ua rau lub embryo. Nws tshwm sim hauv arthropods.
Tom qe raws li cov qe qe:
- Oligocyte qe: lawv me me thiab muaj me yolk.
- Mesolecito Eggs: Medium in size with a moderate of yolk.
- Macrolecithus qe: cov no yog cov qe loj nrog cov qe loj.
Cov theem ntawm embryonic txoj kev loj hlob
- Segmentation: nyob rau theem no muaj cov kev faib tawm ntawm tes los ua kom cov cell uas xav tau rau theem ob. Nws xaus rau hauv lub xeev hu ua blastula.
- Gastrulation: ib reorganization ntawm blastula hlwb tshwm sim, ua rau cov blastoderms (cov txheej txheem txheej thaum ub) uas yog cov ectoderm, endoderm, thiab, nyob rau hauv ib co tsiaj, mesoderm.
- Differentiation and organogenesis: cov ntaub so ntswg thiab cov kab mob yuav tsim los ntawm cov kab mob khaubncaws sab nraud povtseg, tsim cov qauv ntawm tus neeg tshiab.
Kev sib raug zoo ntawm kev loj hlob thiab kub
Kub yog ze ze rau lub sij hawm incubation ntawm ntses qe thiab lawv embryonic txoj kev loj hlob (zoo ib yam tshwm sim nyob rau hauv lwm yam tsiaj). Muaj feem ntau yog qhov qhov kub zoo tshaj plaws rau incubation, uas txawv li ntawm 8ºC.
Qe incubated nyob rau hauv qhov no yuav muaj ntau dua ntawm kev loj hlob thiab hatching. Ib yam li ntawd, cov qe incubated rau lub sij hawm ntev ntawm qhov kub thiab txias (sab nraum qhov pom ntawm hom) yuav muaj qis dua probability of hatching thiab, yog lawv ua., neeg yug los yuav raug kev txom nyem
Ntses embryonic txoj kev loj hlob theem
Tam sim no koj paub cov ntsiab lus ntawm embryology, peb yuav delve rau hauv embryonic txoj kev loj hlob ntawm ntses. Cov ntses yog telolecithal, uas yog, lawv los ntawm cov qe telolecithal, cov uas muaj cov qe hloov mus rau thaj tsam ntawm lub qe.
Zygotic Phase
Cov qe tshiab tshiab tseem nyob hauv zygote xeev mus txog thaum thawj zaug, lub sij hawm kwv yees uas qhov kev sib cais no tshwm sim nyob ntawm hom thiab qhov kub ntawm qhov nruab nrab. Nyob rau hauv lub zebrafish, Danio rerio (feem ntau siv ntses nyob rau hauv kev tshawb fawb), thawj cleavage tshwm sim nyob ib ncig ntawm 40 feeb tom qab fertilization. Txawm hais tias nws zoo li tsis muaj kev hloov pauv thaum lub sijhawm no, cov txheej txheem txiav txim siab rau kev txhim kho tom ntej tau tshwm sim hauv lub qe.
Segmentation Phase
Lub qe nkag mus rau theem cleavage thaum thawj zaug ntawm zygote tshwm sim. Nyob rau hauv cov ntses, qhov segmentation yog meroblastic, vim hais tias kev faib tsis mus kiag li los ntawm lub qe vim nws yog tiv thaiv los ntawm lub yolk, tab sis yog txwv rau thaj tsam uas nws pom lub embryo Thawj qhov kev faib yog ntsug thiab kab rov tav mus rau lub embryo, lawv ceev heev thiab synchronous. Lawv ua rau lub pob zeb ntawm cov hlwb zaum ntawm lub qe, tsim cov discoidal blastula
Gastrulation theem
Thaum lub sij hawm gastrulation, ib qho kev hloov ntawm cov discoidal blastula hlwb tshwm sim los ntawm morphogenetic txav, uas yog, cov ntaub ntawv muaj nyob rau hauv lub nuclei. ntawm cov hlwb sib txawv twb tau tsim, nws yog transcribed nyob rau hauv ib txoj kev uas yuam lub hlwb kom tau ib tug tshiab spatial configuration. Nyob rau hauv cov ntaub ntawv ntawm cov ntses, qhov no reorganization yog hu ua involution Ib yam li ntawd, theem no yog tus cwj pwm los ntawm kev txo qis ntawm cov cell faib thiab me me los yog tsis muaj xov tooj ntawm tes loj hlob.
Thaum lub sij hawm involution, ib co hlwb ntawm lub discoblastula los yog discoid blastula migrate mus rau hauv lub yolk, tsim ib txheej rau nws. Cov txheej no yuav yog endoderm Cov txheej txheem ntawm cov cell sab laug saum toj yuav tsim cov ectoderm Al Thaum kawg ntawm tus txheej txheem, lub gastrula yuav raug txhais los yog, nyob rau hauv cov ntaub ntawv ntawm ntses, discogastrula nrog nws ob lub ntsiab kab mob txheej los yog blastoderms, lub ectoderm thiab lub endoderm.
Phase of differentiation and organogenesis
Thaum lub sij hawm sib txawv, hauv cov ntses, txheej thib peb embryonic tshwm, nyob nruab nrab ntawm endoderm thiab ectoderm, hu ua mesoderm.
Cov endoderm invaginates tsim kab noj hniav hu ua archenteronKev nkag mus rau qhov kab noj hniav no yuav raug hloov npe blastopore thiab yuav ua rau lub qhov quav ntawm cov ntses. Los ntawm qhov no, koj tuaj yeem paub qhov txawv ntawm cephalic vesicle (hlwb tsim) thiab, ntawm ob sab, optic vesicles (lub qhov muag yav tom ntej). Tom qab lub cephalic vesicle, lub neural tube yuav tsim thiab, ntawm ob sab, cov somites, cov qauv uas nws thiaj li tsim cov pob txha ntawm tus txha caj qaum thiab tav, cov leeg. thiab lwm yam kabmob.
Thaum lub sijhawm no, txhua txheej kab mob thaum kawg yuav tsim ntau lub cev lossis cov ntaub so ntswg, yog li:
Ectoderm
- Epidermis thiab paj hlwb
- Pab thiab kawg ntawm txoj hnyuv
Mesoderm
- Dermis
- Musculature, excretory and reproductive organs
- Coelom, peritoneum thiab circulatory system
Endoderm
- Cov kab mob koom nrog hauv plab zom mov: sab hauv epithelium ntawm lub plab zom mov thiab cov qog ua haujlwm.
- Lub luag hauj lwm rau kev pauv roj.
