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.
20 baby teeth: A child will normally have 20 baby (deciduous) teeth. These usually start to come into the mouth (erupt) when the child is around 6 months. The last baby teeth erupt around 2 years old. The baby teeth start to come out when permanent teeth start coming in. This usually starts around 6 years old and child will loose 8 front teeth. Around 10-12 years old, back 12 teeth come out. Ages can vary.