Kosaku Fukaya

Development of the Bovine Ileal Mucosa

The development of the bovine ileal mucosa was studied with particular reference to maturation during the fetal and neonatal period. In this region, by 4-5 months of fetal development, vacuolation of the epithelial cells had occurred on the villi, and the goblet and absorptive cells in the crypts were present. By 6-9 months, the villi were longer and more numerous than in the previous stages. At the same time, the vacuolated cells could be seen predominantly on the upper half of each villus. The absorptive cells and goblet cells were more distinct in the crypt and lower half of each villus. Moreover, the goblet cells showed differences in mucin, while in the submucosa the lymphoid follicles were seen to have enlarged to become a prominent feature of the Peyers patches at this stage. At birth, in suckled animals, the ileal cells on the lower area of each villus and in the crypt appeared more like mature cells. In contrast, there were numerous inclusion bodies in epithelial cells on the upper half of each villus. They appeared in the apical portion of the cytoplasm as vacuoles with stainable or dense contents. By 1 week, however, epithelial cells no longer contained inclusion bodies, and absorptive and goblet cell populations had begun to emerge from the crypts. These histological results suggest that the bovine ileal mucosa has two distinct turning points during its development in the fetus and the neonate. Initially all the mucosal structures are present in fetuses at 6-7 months of gestation, and then the vacuolated cells covering the ileal villi are replaced by mature, nonpinocytosing epithelium which emerges from the crypts on or before the 7th day after birth (ileal closure).

Studies on the Development of the Fetal and Neonatal Bovine Stomach

37 Holstein fetuses and 5 newborn holstein calves were used in a study of the development and neonatal anatomy of the bovine stomach. Care was taken to prevent alterations in pulmonary volume and modification of topographic relationships between stomach compartments. Polymerized synthetic polyester resin was used to form anatomic casts of stomach compartments. This technique provided the basis for a description of relative sizes and relationships of stomach compartments and the nature of the mucosal surfaces.

Developmental changes in the inner surface structure of the bovine large intestine

The developmental pattern of the bovine fetal large intestine was studied with particular reference to the appearance and decline of the intestinal villi during the fetal period. In the bovine large intestine, the first rudimentary villus and goblet cells were seen in the rectum in a fetus estimated to be 3 months old. By 5-6 months, the goblet cells, absorptive cells in the intestinal crypts, and vacuolated cells in the villi were present along all segments of the large intestine. By 8-9 months, the villi have disappeared from the colon and rectum, epithelial cells no longer contain vacuoles, and absorptive and goblet cell populations are emerging from the crypts. These histological results suggest that development in the bovine large intestine follows a recto-cecal gradient and the most distinct turning point during the fetal period is the first disappearance of fetal villi in the rectum of fetuses estimated to be 7 months old. After this stage, the mucous membrane of the colon and rectum matured rapidly before birth. In contrast, the cecum may seem to require further development in perinatal life.

Distribution of the muscle coat at the omasoabomasal junction and its vicinity in cattle.

Detailed studies on the distribution of the muscle coat at the omasoabomasal junction in cattle, especially in the pila omasi, were carried out in order to clarify the mechanism of closing of the ostium omasoabomasicum. Anatomical and histological observations revealed that the muscle coat forming the circumference of the ostium omasoabomasicum is composed of inner circular and outer longitudinal layers. The former was particularly thickened at the end of the sulcus omasi (pila omasi). Joined to the pila omasi was a thick muscle bundle which extended from the labium sinistrum (left lip) of the sulcus reticuli and ran obliquely along the floor of the sulcus omasi. Moreover, on the abomasal side of the ostium omasoabomasicum, vela abomasi were formed in such a manner as to surround the ostium omasoabomasicum. These were continuous with the edges of the sulcus omasi. Judging from its location and muscular structure, the pila omasi may contract in accordance with the contraction of the reticulum. As a result, the ostium omasoabomasicum may be narrowed and the vela abomasi pulled toward the omasum, perhaps obstructing the ostium omasoabomasicum. Accordingly, it is presumed that the retention of contents in the omasum may effectively prevent abomasal contents from moving backward into the omasum.

Anatomical Notes on the Attachment of the Diaphragm to the Abdominal Viscera Particularly to the Stomach in Bovine Fetuses and Neonates

麻布獣医科大学家畜解剖学教室,相模原市229反芻類においては,腹腔臓器に対する横隔膜の付着様式は,反芻に大きな意味を持つものと思われる.本研究においては,牛胎仔および新生仔を用い,とくに胃に対する付着様式をホルマリン固定した材料および胸腔•腹腔ならびに消化管への合成樹脂注入鋳型標本を観察することによって調べた.横隔膜と食道および胃との接着部では,食道尾側端および噴門部の表面には主として右脚から筋線維が分布していた.胃に対する主な付着は左脚からの筋線維によるものであった.胃に対する横隔膜の付着領域は,前方よりみて逆V型を示す.この逆V型を形成する左右両板のうち右板は,右脚からの筋線維とともに噴門付近を被い,背方に向かって第1胃前房背側面から第1胃背嚢右側背縁に至っていた.この逆V型の左板は第2胃背面より後方に向かい,第1胃背嚢左側背縁および脾臓に至っていた.両板の背後側端における連結部は,胎仔においては非常に薄く,新生仔に至って厚く,広く,強靱となった.これらの両板の間および橋状の連結部の下には,疎性の結合組織を伴なった漿膜に被われた盲管状の空隙があり,それによってその下に位置するいわゆるNICKEL et al.のいうSchleudermagenは常に横隔膜への付着から遊離していた.以上の観察結果は反芻機構の考究に一つの参考所見として役立つであろう.