There is a thing I love about butterflies; it’s how they become majestically beautiful out of their old and ugly forms. It’s like having something to marvel at, after some ugly and painstaking process. This reminds me of the thing inside the body they call thyroid gland. Its butterfly shape is the form we see just below our voice box. It’s not so interesting at first but once you get to know how it functions, you are going to marvel and be amused at it too.
Viewing the plain and simple gland, you would not imagine how it does many functions from iodide trapping, synthesis of thyroglobulin, oxidation of iodide, iodination of tyrosine, coupling of T1 and T2, pinocytosis and digestion of colloid, secretion of thyroid hormones to the transport in the blood. With all of these processes, it goes down to one important fact that it serves as a bus transporting protein in the blood flow.
You can imagine the bus… but it would not function by itself without the machineries and the gas, which will make it possible for transportation. We have these machineries and fuel in the form of our thyroid hormones, which are synthesized by attaching iodine atoms to the amino acid tyrosine.
The hormones increase the Basal Metabolic Rate, stimulate the synthesis of additional sodium-potassium pumps, regulate the metabolism, enhance some actions of catecholamines and accelerate body growth with the help pf human growth hormone and insulin. See how the entire bus works? It works from the inspiration of its butterfly form, which seemingly was not something big but indeed, plays a vital role in our bodies.
Going further, how were these machineries formed? The T3 or triiodothyronine and T4 or thyroxin come from the follicular cells and their secretion is increased by the TRH (thyrotropin-releasing hormone) which works like any other thing inside the body that can balance what’s lacking and what’s too much. High iodine suppresses T3/T4 secretion and therefore many other things such as low thyroid hormone levels, low metabolic rate, cold, pregnancy and high altitudes affect production. The calcitonin, which is from the parafollicular cells, is stimulated by High blood calcium levels while low calcium level in the blood inhibits the secretion.
Some suggested video clips are listed below so as to have a better view on the topic:
http://www.youtube.com/watch?v=4l-ky_2DHLA
http://www.youtube.com/watch?v=2AFiMipv63k&feature=related
http://www.youtube.com/watch?v=Vn9crOgnGgs&feature=relatedhttp://www.youtube.com/watch?v=JYb-io13fOA&feature=related
http://www.youtube.com/watch?v=ACjAWYxHtHg&feature=fvw
Here are related topics and good sources for a better understasnding:
http://en.wikipedia.org/wiki/Thyroid_hormone
http://www.oxymega.com/thyroid_gland.html
http://www.endocrineweb.com/thyfunction.html
Principles of Anatomy and Physiology by Gerard Tortora
Photo credits:
http://www.steadyhealth.com/articles/user_files/4540/Image/thyroid1.jpg
http://etc.usf.edu/clipart/3200/3236/butterfly_3_lg.gif
