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.
Cancers are one category of non-communicable diseases that cannot be spread to others. Chicken pox and other conditions caused by viruses are communicable diseases. Non-infectious diseases involving the respiratory system are a class of non-communicable conditions.
While sometimes (incorrectly) referred to as synonymous with  chronic diseases , NCDs are distinguished only by their non-infectious cause, not necessarily by their duration. Some chronic diseases of long duration, such as HIV/AIDS, are caused by infections.on-communicable disease (NCD) is a medical condition or disease that is non-infectious or non-transmissible.