Effects of hypophysectomy and short- and long-term propylthiouracil treatment on the rat thyroid.

The morphology and histology of the post-pharyngeal part of the gastrointestinal tract of the ferret were studied. The oesophagus was a distensible muscular tube. Its mucosa was lined by keratinizing stratified squamous epithelium. The muscle coat was striated throughout except mear the cardia. A cardiac sphincter was present. The stomach was morphologically and histologically very similar to that of man. The duodenum appeared C-shaped and had a mesoduodenum. The bile and pancreatic ducts formed a common duct in the wall of the duodenum. The sphincter of Oddi was present. Brunner's glands were present in the pyloric part of the stomach, and up to the common opening of the bile and pancreatic ducts in the duodenum. The intestine could be differentiated macroscopically and microscopically into small and large intestines. The small intestine distal to the duodenum formed coiled tubes suspended by a mesentery. It was not possible morphologically to differentiate jejunum and ileum. Histologically, however, the distal portion was identifiable as ileum by increasing numbers of goblet cells, and Peyer's patches in the submucosa. Villi were present in the mucosa throughout but there was no spiral or circular fold. The large intestine was a straight dilated tube lying in the left flank and extending from the splenic flexure to the anus in the median plane. It was suspended by a short mesocolon except for the rectal portion in the pelvis. The ileo-colic junction was differentiated morphologically and histologically. There was no caecum, appendix, taeniae coli or appendices epiploicae. The large intestine was not differentiated topographically into ascending, transverse and des