Question

Imagine you are eating something hard like a green guava.What kind of changes takes place in it from the time you bite a piece and put it in your mouth to swallow it?Think what does the saliva in your mouth do?

Answer 1

Hint: Saliva is a watery and typically slightly moist fluid formed in the mouths of certain animals , including humans. Saliva is 98 percent water produced in salivary glands, but contains many important substances, including electrolytes, mucus, antibacterial compounds and various enzymes.

Complete answer:
The digestive functions of saliva include moisturising food and helping to make the food bolus so that it can be swallowed quickly.
Saliva produces the enzyme amylase that breaks down some of the starches into maltose and dextrin. Thus, the digestion of food happens in the mouth, well before food enters the stomach.
As saliva circulates in the mouth, it picks up food debris, bacterial cells, and white blood cells. One to two litres of fluid is excreted into the human mouth every day. Three large pairs of salivary glands and several smaller glands distributed around the surface tissues of the cheeks, lips , tongue and palate contribute to the overall volume of saliva.

Small amounts of saliva are secreted into the mouth constantly, but the presence of food, or even the mere smell or thought of it, will rapidly increase the saliva flow..Saliva helps to regulate the body's water balance; if there is no water, the salivary glands become dehydrated, making the mouth dry, which creates a feeling of thirst and increases the urge to drink.By destroying food waste, dead cells, bacteria and white blood cells, saliva prevents tooth decay and infection. It often contains small amounts of the digestive enzyme amylase that chemically breaks down carbohydrates into simpler compounds.

When I bite a slice of green guava, it's hard, and it may even taste a little bitter. After chewing it properly, however, it becomes soft and sweet. Saliva makes the food moist and also helps to digest it.

Note: You produce quite a lot in a day. Your saliva production changes depending on your posture. It also changes depending on the light. It increases taste sensitivity. It helps battle bacterial infections. It protects against the corrosion of the enamel. Stress will change your salivary flow rate.