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.
Most babies will have their first tooth poke through at any time from 3 to 9 months of age; this can vary greatly, however, so don't worry if your baby begins cutting teeth later or earlier. Babies usually get their teeth in pairs, and the first teeth to appear are the lower central incisors. The bottom teeth will be followed by the upper central incisors, lower and upper lateral incisors, first molars, canines and second molars.