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.
When can I expect my child's first tooth to come in? Teething can begin as early as 4 months of age, but most babies don't get their first tooth until 6 months. Teeth usually come in pairs. The bottom front two teeth typically show up first, followed by the top ones (both sets are called central incisors).