Alimentary canal

• All areas of the alimentary canal contain a four layers arrangement of tissues: serosa, muscularis, submucosa, mucosa

superficial—>deep

• serosa (viseral peritoneum)

  • Membrane that secretes a slippery, watery fluid

  • reduces friction as digestive organs contract and move

• muscularis

  • a layer of muscle extending in two directions:

    • Circular layer

    • longitudinal layer

• submucosa

  • contains glands, nerve fibers, and blood vessels

• mucosa

  • Secretes, mucus, digestive enzymes, and hormones

  • Absorption of nutrients

  • protection from pathogens (lymphatic tissue)