Saturday 3 January 2015

Endocrine (Block 1) - Raging hormones and you

My favourite block of GEMP II. It's quite short, consisting of only five weeks. What I really enjoyed about the block is the logic behind everything. For the most part the hypothalamus, pituitary gland and then the target organs (thyroid gland, gonads, adrenal glands, etc.) are involved. What's nice about this is the feedback loops and axes. I'll give an example below. Oh, and the textbook I used and found super useful was Clinical chemistry by WJ Marshall & SK Bangert. Really great and not too much detail.

Week one is all about the thyroid. We all have a family member who ate just a little too much over Christmas and now suddenly has an "underactive thyroid". Usually not the case (yeah, we all saw the extra helpings, Aunty), but obviously you shouldn't say anything. It won't bode well, trust me. The thyroid axis is a great example of the feedback loops I spoke of. The hypothalamus detects that the body has low levels of thyroid hormone. It then produces thyrotropin releasing hormone (TRH) into what is called the portal circulation (the one in the brain, not the liver), which stimulates the pituitary gland to produce thyroid stimulating hormone (TSH). The TSH enters the systemic vasculature and reaches the thyroid gland (the target organ) and tells it to produce some more thyroid hormone. Once the thyroid hormone levels are replenished, it feeds back to the hypothalamus and says "K, thanks, bye." and the hypothalamus stops producing TRH. Week one doesn't have a course pack. So grab a textbook and make your own one. It won't take all that long.

Week two really should have been week one. The course pack gives the basic details you'll need for the block. Growth hormone is the name of the game. You'll learn of acromegaly and it is said to be relatively uncommon, but you might be lucky enough to see a patient with growth hormone secreting tumours. We did and I was taller than him. Oh, I'm two meters tall, by the way. So I'm easy to spot in the wards if you have any questions.

Ahh 'roid rage!! Week three covers steroids in the body. The biosynthetic pathway is very important and is, of course, not really well done in the course pack. I used Clinical chemistry and Harrison's and Google to get a comprehensive understanding of the entire pathway. Make sure you know this pathway really well. It's a favourite in the exams, both MCQs and written papers. Just a heads up - you'll notice different sources give certain enzymes different names. Try to use as many sources as possible, because you never know which one will pop up in the exam.

Week four and five are very much the same. It handles diabetes mellitus and metabolic syndrome. There are no real problems here with either week. The pharmacology here is really important. It's the bread and butter (low GI and low fat, of course) of endocrinology.

The work isn't all that bad, really. I would just advise you to try and commit the information into your long term memory. The next block was by far my biggest struggle. You will not have time to redo all of endocrine to study for the exams after block two. If you're a graduate who has never done anatomy (I know it was studied for the WAPT, but that was short term memory) I would advise you to make a point of being a boss in endocrine. It will take the pressure off.

Enjoy!


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