The First Architect

Gabrielle Woo - Cornell

Experiences

Embryonic development is by far the greatest feat of bioengineering known to mankind. –Prof. Noden of CUCVM embryology

Now before vet school I would have agreed with my professor on principle, but now that I actually have to remember how the embryo develops, this statement speaks volumes to me. It blows my mind that pretty much all animals, including humans, begin as a mere compilation of cells in the womb.

Take the mammalian heart, for example. It starts out as a hollow cylindrical tube less than 2 mm long (we were given long labeled balloons in class to practice folding) and undergoes a series of impossibly complex, coordinated folds and loops and twisting and compartment separations and cell divisions in the span of a few days to form an almost-mature beating organ – all the while still supplying blood to other body structures in the embryo. These steps are all intricately orchestrated by a host of cell-secreted chemicals and tightly controlled gene expression.

Then upon birth, the heart transitions from an aquatic to terrestrial environment in about 30 seconds. Ever wonder why they thump newborn babies on the back? It opens up the pulmonary artery bed and this abrupt pressure change closes two critical shunts in the heart, redirecting blood flow to the lungs and enabling independent oxygen intake for the first time in the baby’s life. Learning this developmental sequence has taken me several days, a few dozen colour diagrams, 10+ plasticine models, a couple of YouTube videos and a lot of vague gesturing in the air to get my right/left and cranial/caudal bearings straight. And that’s just one organ.

Incredible.