Little Peanut

So I just found out that one of my best friends is pregnant.  She has known for a couple weeks now and is almost eight weeks.  It made me recall lecture and how at about 8 weeks the embryo's skeleton is made up of hyaline cartilage.  At about this time the bone tissue is developing and replacing the cartilage, also called endochondral ossification.  I just remember when my sister was pregnant with my neice she had her first ultrasound at about eight weeks and she looked like a little peanut.  It's crazy that in such a short amount of time developement is so far along.