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.
Your baby is teething when his or her first set of teeth, called primary teeth, break through the gums. Teething usually begins around 6 months of age. But it is normal for teething to start at any time between 3 months and 12 months of age.By the time your child is about 3 years old, he or she will have all 20 primary teeth.The lower front teeth usually come in first.eething usually begins around 6 months of age. But it is normal for teething to start at any time between 3 months and 12 months of age.