The villi , crypts, goblet cells and endocrine cells were presen - ted during 9 th week.十二指肠的绒毛、肠脲 、 杯状细胞和内分泌细胞于第9周胎出现.The wall is thin and almost transparent probably due to atrophy of the villi.肠壁薄,几乎是透明的,这可能是因绒毛萎缩.The...