The lining of the colon is different from the small intestine in that there exists a large number of mucous cells that do not secrete enzymes but rather mucous. The mucous helps protect the wall from the bacterial fermentation inside. About 1.5 L of liquid digestive contents, chyme, pass into the colon.
One important difference between communicable and non-communicable disease is that non-communicable diseases tend to be chronic, which means they last a long time and progress slowly. Communicable diseases are more likely to be acute, which means the disease develops quickly.
In brief: Spread. A communicable disease is a disease many others may get and that is why we have vaccinations. A contagious disease is a disease someone in contact with the person may catch. An infectious disease is a disease that may be spread within the person such as a virus or a bacterial or a fungal infection. An infectious disease may be contagious and communicable but does not have to be. In brief: Spread.