Alimentary canal

Alimentary canal

1. structure of wall (4 layers)

   • • muscosa
     • submucosa
     • muscular layer

2. structure of wall (4 layers)

   • serosa (outer covering)
     • epithelium, CT
     • protection, lubrication
   • muscular layer (outer muscular coat)
     • smooth muscle fibers in circular & longitudinal groups
     • movements of the tube and its contents
   • mucosa (innermost)
     • epithelium, CT, smooth muscle
     • protection, secretion, absorption
   • submucosa (inner muscular coat)
     • loose CT, blood vessels, lymphatic vessels, nerves
     • nourishes surrounding tissues, transports absorbed materials

3. tube innervation by ANS branches

   • parasympathetic impulses
     • general increase in digestive activities
   • sympathetic impulses
     • generally inhibits digestive activities
     • controls mvmt of digesting food through canal
       • contracts certain sphincter muscles

4. movements in tube

   • mixing
   • propelling using peristalsis
   • receptive relaxation (just ahead of peristaltic wave)

5. muscular tube about 8 m long that passes thoracic & abdominopelvic cavities