In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria; and lower left and right ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart.
Best Answer: Well they always calculate due date based on your period. Even the doctor will. If you know your exact date of conception you either add 2 weeks to that date or just count 38 weeks from that date.40 weeks gestation is based on your last period. So technically speaking a women is never actually pregnant for her first 2 weeks.est Answer: Well they always calculate due date based on your period. Even the doctor will. If you know your exact date of conception you either add 2 weeks to that date or just count 38 weeks from that date.
But for the sake of a date, everyone's pregnancy is calculated based on an average. Therefore when you miss your first period, youâre already 4 weeks pregnant. Okay, got it, but how many weeks am I, you askâ¦. To find out how many weeks you are, use our pregnancy calculator. It will give you an estimated due date and estimated date of conception. It will also tell you how many weeks pregnant you are, and how long you have to go until you reach the end of full term pregnancy at 42 weeks. What If I Donât Know When My Last Period Was? If you donât remember when your last period arrived or if youâve not had a period for a while, you can book an early pregnancy ultrasound to try and work out how many weeks pregnant you are.