Histological structures of bursas of Fabricius were observed at the different developmental stages from chicken embryoes to chickens. The results were as follows. The bursa of Fabricius began to develop on the 13th day of post-hatching and its cell aggregated into the nodosity clique underneath the epithelium mucosae. On the 15th day of post-hatching, those cell cliques were surrounded by the flat epithelium and formed the basic structure of folliculus lymphaticus. The number of lymphocytes in the folliculus lymphaticus increased gradually, and the medulla and cortex of a majority of folliculus were not discriminated obviously. Until on the 7th day for chickens, the medulla and cortex of folliculus formed completely and the number of folliculus increased significantly. From 21 to 35 days old, the folliculus lymphaticus transformed from polygon into rectangle. Mucosa epithelial cells increased gradually and their cytoblasts arranged compactly into aline in the basilar part on the 35th day.

本研究觀察了從雞胚到出殼后的不同生長發(fā)育階段法氏囊的組織結(jié)構(gòu)黄色一级视频欧美日韩操逼视频，結(jié)果表明：胚胎13日齡時网站一区啪啪啪，法氏囊開始發(fā)育性色网国产，粘膜上皮下形成結(jié)節(jié)狀細胞集團；胚胎15日齡欧美三级日韩精选，聚集的細胞集團形成初始的淋巴濾泡AⅤ资源网影音先锋；胚胎18日齡到出殼后1日齡，濾泡內(nèi)淋巴細胞數(shù)量增多亚洲黄网站免费，多數(shù)濾泡髓質(zhì)和皮質(zhì)界限仍不明顯国产精品国产精品国产精品；7日齡雛雞法氏囊髓質(zhì)皮質(zhì)分界清晰，濾泡數(shù)量顯著增多高清色视频；21日齡到35日齡国模大尺度A片在线观看，濾泡由多邊形逐漸轉(zhuǎn)變成長方形；在35日齡時91看片淫黄大片，粘膜上皮細胞逐漸增多欧美乱人伦中文在线观看暴力，排列緊密，細胞核緊密排列成直線位于基底部国产一级婬A片AAA毛片久久。