4.The brown products of positive expression of C fos gene were abundant in lamina propia and muscularis in the aganglionic colon and were absent in the proximal dilated segment and normal colon.

• 消化壁一般分为4层，由内向外为粘膜、粘膜下层、肌层和外膜，其中粘膜下层很薄，十二指肠粘膜下层无十二指肠腺。