The 2 carotid arteries on each side of the neck are the most important because they supply blood to the parts of the brain that are involved in thinking, movement, sensation and speech. The other 2 arteries that bring blood to the brain, called the vertebral arteries, supply the brainstem.
The vast majority of babies sprout their first tooth when they're between 4 and 7 months old. An early developer may get his first white cap as early as 3 months, while a late bloomer may have to wait until he's a year old or more.y age 3, your child should have a full set of 20 baby teeth, and they shouldn't start to fall out until his permanent teeth are ready to start coming in â around age 6.
The average child gets his first baby tooth at age six months and then gets three to four new teeth every three to four months. This continues until the second molars erupt at about age two to two and a half years, at which time your child should have all twenty baby teeth. If your child got his first tooth early or finished getting all of his baby teeth early, then he might start losing his baby teeth early too. On the other hand, if he didn't get his first tooth until age twelve or fifteen months, then he might be a little later than average in shedding or losing his first tooth.