Thursday 10 January 2013


The other class I started teaching this week is teeny.  Four students registered, 3 at the first class and only two for the second class today.  But they are in their Final Year and seem to be bright and engaged.  I'm tasked to teach them Environmental Chemistry which is even further from my comfort zone than human physiology.  At least in the Human Physiology class we can be sure that each of us has in their possession a human body.  I thought that the EnvChem class was more 'under control' over Christmas but it's turning out to be a bit steeper to get copy together.  ANNyway, the day before the first class, I came across a list of elements essential to the human body and thought it would be interesting to see how many of them these young biologists could brainstorm.  They were surprisingly good and were prepared to try  the task, even to the extent of not peaking at the periodic table in the front of their hard-back lab-notebooks.  C H O N Fe Na K F Mn Zn Mg Ca P came out in a few minutes. They were delighted when I added Se Co (which I know about because we live on igneous upland soil and we're encouraged to dose our sheep with them) and when I mentioned Iodine one of the girls slapped her forehead.  Se Co Mo and I are very interesting from an EnvChem point of view.
Lots of folk know about Derbyshire Neck (aka goitre) from the prevalence of thyroid problems in the English Peak District.  Iodine is an essential ingredient in the growth hormone thyroxine.  If there is no Iodine then no thyroxine is produced so that a signal goes out to the thyroid saying "make more thyroxine" which is interpreted as "start thyroid cell division", and lickedy-spit our neck is as thick as our head.
I have flagged the idea we should see if there is a correlation between the adundance of the 25 or so human-normal elements in the human body and their abudance in the geosphere.  We expect some outliers because life is about disturbing entropy, but I wonder if there is a significant trend. Watch this space!
I also tasked us all to pick one of the minor elements (minor in abundance, not importance or atomic weight) and write a mini-report outlining its abundance, physical properties, physiological properties, commercial uses and value.  I was going to take Iodine because I'd already started on that, but one of the students has a mother with some sort of thyroid imbalance (no, not Grave's Disease).  So I took Molybdenum and I recommend you to Wikipedia it up: it's spread on cauliflower fields because it's an essential enzyme co-factor and there is enormously long band of prevalence towards esophageal cancer in central Asia because the rocks are Mo deficient . . . I could go on (and on and on and . . .zzzzzzzzz)

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