How much blood do we have when the heart beats for the first time?

It should be between the third and fourth week of embryonic life.

  • 1
    $\begingroup$ Note: there is a heart "beat" but no pumping at 3-4 weeks. The blood vessels and chambers of the heart have not developed. The "beat" is just electrical activity in cells that will eventually become part of the heart. $\endgroup$
    – Bryan Krause
    Feb 6 '20 at 15:08
  • $\begingroup$ From your comment I guess we don't even have blood at 4 weeks $\endgroup$
    – francesco
    Feb 6 '20 at 16:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.