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来自维基百科,自由的百科全书
卵黃囊(英語:yolk sac,拉丁語:saccus vitellinus)是一個連結在胚胎上、由胚胎盤附近的下胚層細胞所組成的膜狀囊。這個構造也在胚胎學的術語中被稱為臍帶囊(拉丁語:vesicula umbilicalis),儘管卵黃囊是比較被廣泛熟知的名稱。卵黃囊提供了胚胎發育早期的所需的血液供應,並且在發育四週後併入原腸中存在。
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