Final answer:
Saliva is continuously produced to keep the oral cavity mucous membranes moist and lubricated, aiding in digestion, oral hygiene, and the protection against infections.
Step-by-step explanation:
The main answer to the question of why smaller amounts of saliva are produced continuously is to ensure that the oral cavity mucous membranes remain moist and lubricated. Saliva, which is predominantly water mixed with ions, glycoproteins, enzymes, growth factors, and waste products, plays a crucial role in not only the process of digestion but also in maintaining oral hygiene and health. In detail, saliva contains salivary amylase that initiates the breakdown of carbohydrates and salivary mucus that helps lubricate and facilitate the movement of food, making swallowing easier. Furthermore, saliva's antibacterial components, such as immunoglobulin A and lysozyme, protect against oral infections by combating harmful microbes that inhabit the mouth.