Kwayar halitta

Organogenesis shine lokaci na ci gaban amfrayo wanda ke farawa daga ƙarshen haƙori kuma yana ci gaba har zuwa haihuwa. A lokacin organogenesis, nau'ikan ƙwayoyin cuta guda uku da suka samo asali daga gastrulation (ectoderm, endoderm, da mesoderm) suna haifar da gabobin cikin kwayoyin halitta.

endoderm na vertebrates yana samar da nama a cikin huhu, thyroid, da pancreas. mesoderm yana taimakawa wajen samar da tsokoki na zuciya, tsokoki, tsokoshi mai santsi, kyallen takarda a cikin koda, da jajayen ƙwayoyin jini. ectoderm yana samar da kyallen takarda a cikin epidermis kuma yana taimakawa wajen samar da neurons a cikin kwakwalwa, da melanocytes.

Kwayoyin kowane nau'in nau'in kwayoyin cuta guda uku suna fuskantar bambance-bambance, tsari inda sel marasa ƙwarewa ke zama mafi ƙwarewa ta hanyar bayyana takamaiman tsarin kwayoyin halitta. Bambance-bambancen tantanin halitta yana gudana ta hanyar siginar tantanin halitta. Bambance-bambancen yana tasiri ta hanyar sigina na waje irin su abubuwan haɓaka da ake musayar su zuwa sel kusa da ake kira siginar juxtracrine ko zuwa ga sel makwabta a kan ɗan gajeren nesa wanda ake kira siginar paracrine. Sigina na cikin salula - kwayar tantanin halitta mai siginar kanta (siginar autocrine) - shima yana taka rawa wajen samuwar gabobin. Waɗannan hanyoyin sigina suna ba da damar sake tsara tantanin halitta da kuma tabbatar da cewa gabobin suna samuwa a takamaiman wurare a cikin kwayoyin halitta. Za a iya yin nazarin tsarin organogenesis ta amfani da embryos da organoids..

Jiki da aka samar da kwayoyin halitta

Kwayoyin precursor na jijiyoyi suna ninkawa kuma suna tsawo don samar da bututun jijiyoyi. Mesoderm cells sun taru don samar da sandar da za ta aika da sigina don sake jagorantar ectoderm cells a sama. Wannan ninka tare da bututun jijiyoyi ya kafa tsarin juyayi na tsakiya.

Endoderm shine mafi yawan kwayoyin cuta na ciki na tayin wanda ke haifar da gabobin ciki da na numfashi ta hanyar samar da suturar epithelial da gabobin kamar hanta, huhu, da pancreas. Mesoderm ko tsakiyar germ Layer na amfrayo zai samar da jini, zuciya, koda, tsokoki, da kyallen takarda. Ectoderm ko ƙwanƙwasa ƙwaya mai girma na amfrayo mai tasowa yana haifar da epidermis, kwakwalwa, da tsarin juyayi.

Hanyar samar da kwayar halitta

Yayin da kowane Layer germ ke samar da takamaiman gabobin, a cikin 1820s, masanin ilimin mahaifa Heinz Christian Pander ya gano cewa sassan ƙwayoyin cuta ba za su iya samar da gabobin su ba tare da hulɗar salula daga wasu kyallen takarda ba. A cikin mutane, gabobin ciki suna farawa a cikin makonni 3-8 bayan hadi. Yarinyar ƙwayoyin cuta suna samar da gabobin ta hanyoyi guda uku: folds, tsagewa, da ƙumburi. Folds suna samuwa a cikin takardar sel kuma yawanci suna samar da bututun da ke kewaye wanda zaku iya gani a cikin haɓakar bututun vertebrates. Rarraba ko aljihu na iya samuwa a cikin takardar ƙwayayen sel waɗanda ke yin vesicles ko elongations. Huhu da gland na kwayoyin halitta na iya tasowa ta wannan hanyar.

Mataki na farko a cikin organogenesis don chordates shine haɓakar notochord, wanda ke haifar da samuwar farantin jijiyoyi, kuma a ƙarshe bututun jijiya a cikin haɓakar kashin baya. Ci gaban bututun jijiyoyi zai haifar da kwakwalwa da kashin baya. Vertebrates suna haɓaka jijiyar jijiyoyi wanda ya bambanta zuwa sassa da yawa, ciki har da ƙasusuwa, tsokoki, da sassan tsarin juyayi na tsakiya. Bambance-bambancen ectoderm a cikin jijiyar jijiyoyi, bututun jijiyoyi, da ectoderm na sama wani lokaci ana kiran su da jijiya kuma amfrayo a cikin wannan lokaci shine neurula. Coelom na jiki yana samuwa daga tsagawar mesoderm tare da axis na somite

Tsarin shuke-shuke

A cikin tsire-tsire, organogenesis yana faruwa ci gaba kuma yana tsayawa ne kawai lokacin da shuka ya mutu. A cikin harbin, harbe-harbe apical meristems akai-akai suna samar da sabbin gabobin gefe (ganye ko furanni) da rassan gefe. A cikin tushen, sabbin saiwoyin gefe suna fitowa daga nama mai rauni mai rauni (misali xylem-pole pericycle a cikin ƙirar Arabidopsis thaliana). A cikin vitro da kuma mayar da martani ga takamaiman cocktails na hormones (yafi auxins da cytokinins), yawancin kyallen jikin tsire-tsire na iya rarrabuwa kuma su samar da tarin rarrabuwar sel masu ƙarfi da ake kira callus. Organogenesis na iya faruwa daga waɗannan sel. Nau'in gabobin da aka kafa ya dogara ne akan adadin dangi na hormones a cikin matsakaici. Za a iya haifar da kwayoyin halittar shuka a cikin al'adun nama kuma a yi amfani da su don farfado da tsire-tsire.