Thick-walled tube with a narrow lumen, the wall contains mucosa, muscularis and adventitial layers:

• mucosa
  • forms longitudinal folds #1, #2;
  • lined with a pseudostratified epithelium, containing prismatic cells with long microvilli (stereocilia) on the surface and intercalated cells;
  • lamina propria is formed by loose connective tissue with a high content of elastic fibers;
• muscular layer is the thickest and is formed by three layers with blurred edges made up from smooth muscle cells (longitudinal internal and external, circular middle);
• adventitia is formed by loose connective tissue, contains small blood vessels #1, #2.