1. The document describes the general histological structure of the gastrointestinal tract, specifically focusing on the esophagus of cats and dogs. 2. It notes that the esophagus of dogs contains mucous and compound tubulo-alveolar glands in the submucosa that drain into the lumen via ducts, while the esophagus of cats lacks glands and has a well-developed muscularis mucosa. 3. The document also discusses the gastroesophageal junction and identifies histological structures like the inner circular and outer longitudinal muscle layers, as well as Auerbach's plexus.

1. General Plan of GIT IC OL A (1) M : Mucosa: Epithelium Lamina Propria Muscularis Mucosa (3) MUSCULOSA IC: Inner circular OL: Outer longitudinal (4) A: Adventitia/ Serosa M S (2) S: Submucosa

2. E E : Non-Keratininzed Stratified Squamous Epithelium on a clear wavy BM.

3. G D Oesophagus Dog G: Oesophageal glands in submucosa: *Mucous Glands *Compound tubulo-alveolar *D: Ducts pierce mucosa to open into lumen G D

4. Oesophagus Cat Well-developed Muscularis Mucosa No Glands in submucosa

5. Digestive Tract Histology Department / Faculty of Medicine / Cairo University

6. Digestive Tract Histology Department / Faculty of Medicine / Cairo University

7. Auerbach´s Plexus between the inner circular ( C) and outer longitudinal (L) muscle layers Arrows:

8. Gastro-oesophageal junction Oesophageal glands Inner oblique submucosa Gastric glands non ker. St . sq.epith.

9. Gastro- Oesophageal Junction

10. Data Show Trial Exam for Oesophagus

11. Identify the organ. 2) Mention the type of epithelium (E). 3) Black arrow Blue arrow Green arrow. Astreix. Arrow head . Square. E ▲ ■ 1 *

12. 1) Identify the structures Indicated by the arrow. Be specific for the type. 2) In which layer are they present? 2

13. E * Identify (E), Arrows: Black, Blue & Green. Identify astreix. 3

14. Is this slide oesophagus cat or dog? Mention the criteria for differentiation. 4

15. 1 2 Identify the type of junction. 2) Which side is 1 and which is 2 ? 3) Identify: Arrows : Black, red & green. 4) Identify layer marked by astreix. * 5