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.
Infectious diseases are caused by germs, such as viruses, bacteria, and parasites. Contagious or communicable diseases are those that can be spread from one person to another. Infectious diseases that commonly occur among children are often communicable or contagious and may spread very easily from person to person.