(5 weeks was Monday, July 28th)
This is the picture that Jonathan drew of the baby, he calls it Tad.This week:
Your little embryo, which at this point resembles a tadpole more than a baby (complete with tenny tail), is growing fast and furious and is now about the size of an orange seed – still small but a lot bigger than it’s been. This week, the heart is starting to take shape. In fact, the circulatory system, along with the heart, is the first system to be operational. Your baby’s heart (about the size of a poppy seed) is made up of two tiny channels called heart tubes – and though it’s still far from fully functional, it’s already beating – something you might be able to see on an early ultrasound. Also in the work is the neural tube, which will eventually become your baby’s brain and spinal cord. Right now the neural tube is open, but it will close by next week.
(from: What to Expect when you’re Expecting)