原来,在受精卵着床于子宫内膜之后,胚胎的部分胚膜和相邻的母体子宫内膜就会逐渐融合形成胎盘。胎盘与胚胎之间又会逐渐形成包裹着脐动脉、脐静脉、脐尿管的管状结构,这个结构就是脐带,我们
%C8%AB%D7%D4%84%D3%93%E4%BF%CB%CF%B4%C5%C6%99%43%D2%95%EE%6C%2D%A1%BE%40%31%33%37%31%30%30%37%39%36%38%38%A1%BF
%C8%AB%D7%D4%84%D3%93%E4%BF%CB%CF%B4%C5%C6%99%43%D2%95%EE%6C%2D%A1%BE%40%31%33%37%31%30%30%37%39%36%38%38%A1%BF
%C8%AB%D7%D4%84%D3%93%E4%BF%CB%CF%B4%C5%C6%99%43%D2%95%EE%6C%2D%A1%BE%40%31%33%37%31%30%30%37%39%36%38%38%A1%BF
%C8%AB%D7%D4%84%D3%93%E4%BF%CB%CF%B4%C5%C6%99%43%D2%95%EE%6C%2D%A1%BE%40%31%33%37%31%30%30%37%39%36%38%38%A1%BF




