Sputum

Sputum, less formally saliva, and more colloquially spit is a digestive fluid produced by the salivary glands surrounding the mouth. Sputum aids with chewing and contains several digestive enzymes that start the breakdown of food into usable chemicals. One of the main enzymes in sputum converts starch into sugars.
Normal sputum should be white and frothy, with no trace of color or blood. Green or yellow in the sputum usually indicates an infection in the lungs or bronchial passages. Blood in the sputum usually requires a good look for sources of bleeding, but is often the result of gum disease. Lack of sputum, or dry mouth, is often a result of dehydration, but can indicate an underlying condition. Excess sputum, or drooling, is often the sign of an underlying neurological disorder, but can also indicate difficulty swallowing.
Like blood, a culture can be taken from a sputum sample as many infections start in the mouth or spread there once a patient is infected. However, it is normal for some bacteria to be in the mouth, although the most common bacteria is the primary cause of dental caries, the most common disease in the world. However, dry mouth can often lead to even worse dental problems as there are chemicals in sputum that also help fight tooth decay.
Sputum is often consumed with food and requires the patient to drink fluids to replenish it during a meal, particularly where the meal is very low in water content, such as bread or crackers.
Saliva at Wikipedia
Category:Physiology