[ 2007-02-09 11:04 ]
Saliva is produced by the salivary glands.
There are three pairs of big salivary glands and countless small salivary glands
distributed on our lips, cheeks, palates and some other places. The major part
of saliva is water. Saliva also contains some amylases and sticking proteins. Saliva moistens
the oral cavity, helping us swallow and digest. Tests show that a normal adult
secretes 1000-1500 ml of saliva in a day. Under normal circumstances, people
swallow the saliva consciously and unconsciously.
Because newborn babies' saliva secreting functions are not perfect, they
generally don't slobber. After four
months, because of the increase in food intake, babies secrete a little more. In
six months, they begin to teethe. The gingival nerve is stimulated and reflectively
increases the secretion of the salivary glands. At this time, children have not
yet formed the ability to properly swallow saliva, and so the excess saliva will
'drool' out of the corners of their mouths. This is the most obvious in one and
two year olds. As children grow older, their saliva-swallowing abilities will
improve, and the slobbering will stop.
Saliva can be acidic, so it can stimulate the skin. Parents should often wipe
saliva for children; wash the skin with warm water and then use lotion to
protect the skin of children's chins and necks. The handkerchiefs used to wipe
the saliva should soft enough not to damage partial skin.
（北京林业大学通讯员黄典钰供稿 英语点津 Annabel编辑）