Thursday, 27 February 2020

Esophagus, histology, discussion, viva, oral questions

  1. What are the layers of esophagus?
    • From lumen outwards
      • Mucosa
      • Submucosa
      • Muscularis externa
      • Serosa or adventitia
  2. Name the layers of mucosa?
    • Epithelial layer lined by stratified squamous non-keratinized epithelium
    • Lamina propria
    • Muscularis mucosa
  3. Why is it lined by stratified squamous non-keratinized epithelium?
    • It protects the esophagus from physical wear and tear occurring when it comes in contact with various types of food (hot, cold, spicy, junk)
  4. What are the components of lamina propria?
    • Loose connective tissue
    • Blood vessels
    • Nerves
    • Lymphatics
    • Smooth muscle cells
  5. What is muscularis mucosae?
    • Muscularis mucosae is a thin layer of smooth muscle arranged as longitudinal layer around the lamina propria
  6. what are the components of submucosa?
    • Dense connective tissue
    • Larger blood vessels
    • Mucosal or esophageal glands
    • Submucosal or Meissner's plexus of autonomic nerves
  7. What are the components of muscularis externa?
    • In the upper 1/3rd skeletal muscle layer
    • In the middle 1/3rd smooth and skeletal muscle layer
    • In the lower 1/3rd only smooth muscle layer
    • Myenteric (Auerbach's) plexus of autonomic nerves along thin layer of connective tissue
  8. What is serosa or adventitia? 
    • Abdominal part of esophagus: Serosa
    • Thoracic part of esophagus: Adventitia
  9. Difference between serosa and adventitia
Serosa
Adventitia
Thin layer of loose connective tissue with numerous blood vessels, lymphatics, adipose tissue covered by simple squamous epithelium (mesothelium)
Loose connective tissue with numerous blood vessels, lymphatics, adipose tissue which merges with surrounding tissues. Mesothelium is absent

10. What is mesothelium?
    • It is a simple squamous epithelium covering a thin layer of loose connective tissue in the abdomen surrounding the viscera
11. What is the function of Meissner's plexus?
  • Meissner’s plexus regulates the configuration of the luminal surface, controls glandular secretions, alters electrolyte and water transport and regulates local blood flow

12. What is the function of Myenteric plexus?
  • Myenteric plexus supplies the GIT and controls the gastric motility

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