Saptamana 12 de sarcina (dezvoltarea sarcinii pe saptamani)

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Inapoi la Blog Tei Vezi si alte articole din DEZVOLTAREA SARCINII PE SAPTAMANI

La 12 saptamani, fatul masoara de obicei intre 5,4 cm si 7 cm de la cap pana la bazin si cantareste aproximativ 8,5 g pana la 14,2 g. La 12 saptamani bebelusul este sustinut prin intermediul placentei, care este acum complet formata, desi va continua sa se dezvolte pana in saptamana 14.

Organele vitale sunt acum dezvoltate in masura in care sunt capabile sa indeplineasca sarcini mai complexe. Ficatul produce acum bila, iar rinichii secreta urina in vezica. Tractul digestiv fetal manifesta peristaltism intestinal, contractiile musculare necesare pentru a digera alimentele, iar maduva osoasa produce globule albe. Glanda pituitara din creier produce hormoni reproductivi atat la barbati, cat si la femei. Fatul de sex feminine a dezvoltat deja ovare, in timp ce cel de sex masculini isi dezvolta testiculele.

Pana la 12 saptamani de gestatie, bebelusul raspunde la atingeri usoare oriunde pe membre sau pe fata.

Primele miscari oculare inregistrate au loc in saptamana 12.

Fatul incepe sa inghita lichid amniotic in jurul saptamanii 12 de gestatie. Comportamente mai complexe pot fi observate la 12 saptamani, cum ar fi loviturile cu picioarele, loviturile cu pumnul si strangerea pumnilor. Bebelusul continua sa-si atinga fata, sa se intinda si sa caste.
Inca de la 12 saptamani, se formeaza conexiuni intre talamus si restul creierului, despre care cercetatorii sustin ca ajuta la procesarea senzatiilor, inclusiv cea de durere.

Amprentele digitale incep sa se formeze in jurul saptamanii 12. Pana la 26 de saptamani, modelul final de amprente se fixeaza permanent. Unghiile de la degetele de la maini si de la picioare, de asemena, incep sa creasca.

Sunetele sunt detectate in cohlee, un tub in forma de melc din urechea interna. Cohleea tanara creste in spirala, astfel incat pana in saptamana 12 a parcurs doua rotatii si jumatate si a atins forma sa adulta.

Pana la 8 saptamani de sarcina, apar primele semne ale unui dinte pe masura ce mici muguri dentari incep sa creasca in interiorul maxilarului bebelusului. In urmatoarele cateva saptamani, fiecare mugure dentar trece prin etapele de mugure, calota si clopot, luand treptat forma unui viitor dinte. In acest timp, celule specializate incep sa formeze coroana, pulpa, smaltul si dentina dintelui. In jurul saptamanii 12, un al doilea mugure dentar apare in spatele fiecarui dinte de lapte. Acesti muguri ascunsi vor deveni in cele din urma dintii permanenti ai adultilor.

La 12 saptamani de gestatie, aproximativ 10% din greutatea corporala totala este reprezentata de ficat. In acest moment, ficatul este principala sursa de globule rosii si albe fetale. In aceasta saptamana, maduva osoasa incepe, de asemenea, sa produca celule sanguine insa aceasta nu va deveni principala sursa de globule rosii pentru copil decat la aproximativ 7 luni de gestatie.

Intre saptamanile 8 si 12, intestinele cresc atat de repede incat se extind in afara corpului fatului, fiind plasate intr-o cavitate din cordonul ombilical. Pana in saptamana 12, abdomenul fatului este suficient de mare incat intestinele incap din nou in abdomen.

Bibliografie

Week 12 of pregnancy (Days 84-90), HCA Healthcare UK
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Week 12, Charlotte Lozier Institute official website