• Question: What makes the heart the shape that it has?

    Asked by Zyatu to Praveen, Michael, Cristina on 13 Nov 2015. This question was also asked by caitlin.
    • Photo: Michael Schneider

      Michael Schneider answered on 13 Nov 2015:

      The most primitive heart, in flies, is just a long, straight, pulsing tube. So is the heart, in more advanced animals including humans, very early in embryonic life. As the heart matures, in addition to getting progressively larger, it goes through a specific series of steps. These include looping towards the right, the outer face of the loop becoming thicker, and portions of the loop narrowing to create the future heart valves. All of this is controlled by many genes, acting together to make in mammals the normal four-chambered heart.

      Here’s a nice picture of it:

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