What is the function of saliva?
Saliva is a watery, colourless fluid which is produced by some glands inside our mouth. It contains 98% water and 2% enzymes. The most important enzyme is ptyalin which helps us in digesting the food we chew and eat. While chewing, the salvia joins the food and helps in converting the food into energy. It also helps as a lubricant to help food pass down the food-pipe more easily. Saliva keeps the mouth moist and another enzyme called lysozyme in it helps in killing the bacteria entering the mouth.
The three pairs of glands which produce saliva are (i) parotid glands (ii) sublingual glands, and (iii) submandibular glanas. These are located between the bones of the ears and the jaws, under the tongue, and under the lower jaws respectively.
These glands are very active and sensitive. Even if you think of food or imagine yourself eating your favourite dish the saliva from these glands begins to flow. These glands are able to adjust the quantity and nature of the saliva according to immediate requirement.
The three pairs of the salivary glands produce different quantities of saliva ‘for different requirements of the body: The largest I -Pair near the ears (parotid) give larger quantities of watery saliva to I dilute and moisten the food. The glands near the lower jaw give a sticky saliva to make the food ‘slippery’ for easier transfer. All the salivary glands have parasympathetic and sympathetic nerves reaching, and their stimulation produces saliva.
Small children produce more saliva. This happens because the salivary glands are more active for a few years after birth. About 1.5 liters of saliva is secreted in the mouth of an average person every day.