GIT

Slide 1 X50 In this cross section through the upper third of the oesaphagus note: Mucosa with epithelium, lamina propria and muscularis mucosae and submucosa. Which layer(s) of the wall is/are not present in this field? In which layer do you see the deep eosophageal glands? What do they secrete? Explain the presence of lymphoid tissue around the duct. TECHNIQUE: Haematoxylin and eosin A313

Slide 2 X400 In this cross section through the upper third of the oesophagus note: The muscularis externa. The two layers of muscle (what type?) separated by connective tissue supporting a nerve and large ganglion cells (a nerve plexus). Name the nerve plexus. What is its function? Account for the presence of this particular muscle type in this region of the oesophagus. TECHNIQUE: Haematoxylin, eosin and elastic stain CB32

Slide 3 X50 In this section through the mucosa of the fundus of the stomach note: The gastric pits lined by palely stained epithelium; The closely packed simple tubular glands extending from the muscularis mucosae and opening into the gastric pits; The lamina propria between the glands. Why are the middle portions of each gland eosinophilic and the basal portions basophilic? TECHNIQUE: Haematoxylin and eosin B454

Slide 4 X50 The magenta colour where mucus is present in The surface epithelial cells; The epithelial cells of the gastric pits; and The neck of the glands (mucous neck cells). What is the function of the abundant mucous secretion in the stomach? TECHNIQUE: PAS and Haematoxylin C115

Slide 5 X1000 In this section through the mucosa of the fundus of the stomach note: The brightly eosinophilic parietal (oxyntic) cells in the middle regions of the gastric glands The frothy looking cytoplasm of the mucous neck cells. Why are the parietal cells so called? What shape are they? What do they produce? Why are they so intensely eosinophilic? What are the pale-stained regions in the parietal cells? (See electron micrograph). Account for the appearance of the cytoplasm in the mucous neck cells. TECHNIQUE: Haematoxylin and eosin B450

Slide 6 X1000 In this section through the mucosa of the fundus of the stomach note: The chief (zymogenic) cells in the basal region of the gastric glands (the eosinophilic secretory granules have not been adequately fixed). What shape are the chief cells and where are their nuclei situated? What do they secrete? Account for the basal basophilia and the apical eosinophilia of the chief cells. What are other cell type can you see at the base of these fundic glands? TECHNIQUE: Haematoxylin eosin and elastic stain B45

Slide 7 X50 Compare the structure of this section to that in slide 8. This slide demonstrates a plica circularis which is characteristic of the small intestine. Note: The core of submucosa containing the duodenal (Brunner’s) gland; Villi and intestinal glands, lined by a continuous epithelium (what type?); and A duct of the duodenal gland passing through the muscularis mucosae and entering the mucosa. How is the surface area of the small intestine increased? For what function? How is the surface area of the columnar cells increased? TECHNIQUE: Haematoxylin and eosin CB84

Slide 8 X100 This slide has been stained to demonstrate PAS positive mucus. Note the magenta colour where mucus is present in: The goblet cells of the villi and intestinal glands; The secretory end pieces of the duodenal (Brunner’s) glands in the submucosa; and One of the ducts of the duodenal glands opening into an intestinal gland. What is the function of the abundant mucous secretion in the duodenum? TECHNIQUE: Periodic acid – Schiff and Haematoxylin A618

Slide 9 X100 Note: The abundance of lymphoid tissue in the lamina propria and the submucosa (nodular or diffuse?); The eroded surface epithelium; and The discontinuous and barely discernible muscularis mucosae. What is the function of the appendix? TECHNIQUE: Haematoxylin and eosin B486

Slide 10 X50 This section was cut through one of the teniae coli. Note: The oblique/longitudinal/transverse section through the colonic glands (what type?) in the mucosa; The eosinophilic muscularis mucosae; The submucosa with large blood vessels and Two layers of muscle in the muscularis externa In which plane was this section cut? Account for the thickness of the outer longitudinal band of muscle in this region. TECHNIQUE: Haematoxylin and eosin CB91