Heart formation

<< View all animations

The embryo’s heart is the first organ that forms. It is derived from two primitive heart tubes. Between days 18 to 30, the primitive heart tubes fuse together, bend and twist to form a simple version of the heart. About half way through this process, the heart starts to beat.

At 2 months, the heart bears a close resemblance to what it will look like after the baby’s born. The resemblance is only superficial since the inside of the heart is different in both form and function.

In a newborn’s heart, oxygen-poor blood from the body enters the right atrium, goes to the right ventricle where it is pumped to the lungs to become rich with oxygen. From the lungs, the blood flows back to the heart filling the left atrium then enters the left ventricle. The left ventricle pumps the oxygen rich blood through the aorta, which carries it to the rest of the newborn’s body.

The fetal heart has the same basic components as the newborn heart, but there are a couple important differences. Because the placenta is providing all of the oxygen the fetus requires, its lungs are not needed to perform this task. Much of the fetus’ blood is detoured away from the lungs through two openings or connections: the foramen ovale, which connects the right and left atria, and the ductus arteriosus, which connects the aorta and the pulmonary artery. These two important connections will remain open up until the time of birth.

Within thirty minutes after the baby’s first breath, the ductus arteriosus will completely close, and the flap of the foramen ovale will shut off like a valve. This happens because of an increase in pressure on the left side of the heart, and a decrease on the right side. These changes in the heart anatomy cause the blood to flow to the lungs, which will take over their lifelong job of supplying oxygen to the body.

 


Need an appointment? Request one online 24 hours/day, 7 days/week or call 800-789-PENN (7366) to speak to a referral counselor.

 

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

©Copyright A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

Related Links
Request an Appointment Online or call
1-800-789-PENN (7366)

 

   
   

 

About UPHS   Contact Us   Site Map   Privacy Statement   Legal Disclaimer   Terms of Use

The University of Pennsylvania Health System, Philadelphia, PA 1-800-789-PENN © 2014, The Trustees of the University of Pennsylvania