Cardiac Valve Formation

Our hearts began beating as early as four weeks after conception, even before they had fully developed. Heart valves formed shortly afterwards, ensuring blood always flows in the right direction – a similar valve is developing in this beating zebrafish heart. By recording layers of endocardial cells lining the zebrafish heart (artificially colored grey here), researchers were able to assemble this 3D video of two consecutive heartbeats. Looking a bit like a school of swarming fish, the endocardial cells reveal the shape of the heart chambers pumping blood between the atrium (outlined on the right) and ventricle (on the left).

Later in the video, the second heartbeat highlights cells in the developing valve (known as valve leaflets) in bright colors. The leaflets come together to close the opening between the atrium and ventricle, the atrioventricular canal – a developmental milestone that allows life to progress past this delicate early stage.

Article:
http://dev.biologists.org/content/143/12/2217

Video source:
https://vimeo.com/173342370
Info by John Ankers via BPoD

The Heart Wall – Read & Learn:
http://biology.about.com/od/Heart/ss/The-Heart-Wall.htm

AV Deffect
Atrioventricular canal defect is a combination of heart problems resulting in a defect in the center of the heart. The condition occurs when there’s a hole between the heart’s chambers and problems with the valves that regulate blood flow in the heart.

Sometimes called endocardial cushion defect or atrioventricular septal defect, atrioventricular canal defect is present at birth (congenital). The condition is often associated with Down syndrome.

Atrioventricular canal defect allows extra blood to flow to the lungs. The extra blood forces the heart to overwork, causing the heart muscle to enlarge.

Untreated, atrioventricular canal defect can cause heart failure and high blood pressure in the lungs. Doctors generally recommend surgery during the first year of life to close the hole in the heart and to reconstruct the valves.

Reference:
http://www.mayoclinic.org/diseases-conditions/atrioventricular-canal-defect/basics/symptoms/con-20024932  

Source: Scents of Science – Think different. (myfusimotors.com)