Friday, 26 May 2017

Naming of heart

For more than four years, I've been bloggin' about the process of teaching in The Institute. It will be the work of moments to find out where that place actually is . . . and indeed the name that appears on my pay-cheque. But I have been careful to formally anonymise the place where I work. I've also been pretty careful to be silent about my colleagues: there is neither catharsis nor future in unloading about their oddities in this public forum. My students haven't been so well protected from criticism but I hope that I have been respectful about them and their mistakes. It's important to say that being wrong is not a bad thing; realising you are wrong is after all the first step to getting things right. And I don't think, on balance, that I have moaned about them more than I have celebrated their successes.  Earlier this year I set my 1st Year Human Physiology students a task under exam conditions:
Make a sketch of the heart, naming i) the main chambers and showing where 
the blood is oxygenated or not ii) the valves, indicating the direction of blood flow.
This is easy to do only if you haven't attempted it!
1. The heart is a 3-dimensional object and you are asked to flatten onto a 2-D page.
2. As the heart develops, it makes an axial rotation so the blood-vessels are entangled at the top.
3. All the blood vessels are attached at the top. This is particularly hard for showing the connexion of the L and R ventricles, which form the lower part of the heart, to the outgoing vessels [aorta & pulmonary artery]. The question is essentially a naming of parts but it is cast in such a way that should elicit an understanding of the process - the flow-diagram, if you will. I got a variety of responses: some beautiful anatomically correct drawings; some functional cartoons bearing little resemblance to reality. And almost everyone forgot at least one valve or some other functional part. Then I got this:
What I like about this answer is that most of the heart-parts are named . . . but in a totally random way.
  • the left ventricle and the tricuspid valve float in the middle unattached to anything else [island in centre] - tricuspid usually on the edge of the right ventricle;
  • the right ventricle is correctly attached to the pulmonary artery but are likewise totally independent [island on left] they need a pulmonary semi-lunar vale between them; 
  • there is a mysterious third blob [island on right] where two key parts on the list - pulmonary and bicuspid valves - are propping each other up as another independent republic
  • there is neither left nor right atrium
    • indeed there is no septum separating the left side from the right
  • the inferior vena cava is by-passing the heart entirely [bottom L]
  • are the three funnels at the top one aorta or three? One is labelled as 'to lungs' and that's not true of any aorta.  This has nothing to do with a triple bypass
I gave the student some credit for getting most of the heart-part inventory and spelling things correctly but it is clear that s/he doesn't have the least idea what happens inside her heart. I have repeatedly commented on the naming of parts in science: how names are essential to establish what we are talking about but largely irrelevant for revealing out how things work. There are some exceptions, of course: pulmonary semi-lunar valve gives clues as to its shape, location and function. Meles meles, on the other hand, just tell us what Romans called a badger - nothing about its habitat, family structure, gestation period, diet, size or colour.  As Richard "Nobel" Feynman famously said [parrotting his Dad]: “You can know the name of a bird in all the languages of the world, but when you're finished, you'll know absolutely nothing whatever about the bird... So let's look at the bird and see what it's doing -- that's what counts.” Option: great man tells the story on film.
It is always nice to read Henry Reed's dreamy WWII poem Naming of Parts.
I don't usually snicker at the wild and woolly things students put down in exams; but eeee I 'ad to larf at this answer to the question sketch the crystal structure of the two forms of pure carbon: graphite and diamond.
I bet you €5 that student spent far too much time as a girl watching Disney princess movies and drawing tiaras.

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