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.
Dental development. All 20 baby teeth usually come in by the time your child is three years old. Tooth eruption varies from child to child. Most children start to get teeth around six months, but it is not unusual for teeth to begin appearing as early as three months or as late as one year.