Sorry to ask a stupid question, but what do these terms actually refer to?
I have got a reassurance scan on Wednesday (7+4 gestation) and when I have been 'googling' about it the terms foetal pole and yolk sac keep appearing but no real explanation of what they are?
The only sort of explanations I can find are on Wikipedia but it just reads as gooble-de-gook 
Can anyone educate a new and clueless first-time-mum-to-be... 
Thank you x