• enzymes
  • In this process, enzymes are secreted into the environment surrounding the organism, where they break down an organic material, and some of the products diffuse back to the organism. (wikipedia.org)
  • mucosa
  • Neck cells produce mucopolysaccharide, glycoprotein, and HCO 3 - in response to stimulus by prostaglandins, which protects mucosa and lubricates food. (lifeinthefastlane.com)