The wall of digestive tube was composed of mucous membrane, thin submucosa, tunica muscularis and tunica adventitia, but duodenal gland in duodenum was not found.
The wall of digestive tube was composed of mucous membrane, thin submucosa, tunica muscularis and tunica adventitia, but duodenal gland in duodenum was not found.
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。