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 the most accurate way to date a pregnancy is via ultrasound measurement of the fetus's crown-to-rump length between eight and 12 weeks. Extreme fatigue is very common in the first trimester of pregnancy. Your metabolic rateâthe amount of energy you burn just to existâis way above normal then, explains Low.