九成人都不知道的甲狀腺重要作用；教你如何看懂甲狀腺驗血報告 what exactly is the thyroid doing to our body?

as you may know thyroid diseases are very common eg hyperthyroidism and hypothyroidism are often encountered but if I ask you what is the function of the thyroid gland I reckon 90% of people would not be able to answer today let's talk about the thyroid gland and at the end of this video I'll tell you how to interpret a thyroid function test so make sure you watch until the end the thyroid gland is a butterfly shaped organ in front of the neck a little bit below the Adam's apple the thyroid gland is responsible for the secretion of thyroid hormones like many other substances in human body the thyroid hormone must be controlled within a certain level in order to allow normal functioning of the body too much too little can lead to serious problem as I said thyroid gland secrets thyroid hormone but it cannot control how much hormone should be secreted how much thyroid hormone is secreted is determined by a control centre in the brain this centre tells the thyroid gland how much thyroid hormone it should churn out in order to maintain a stable level in the blood for example if the level of thyroid hormone in the bloodstream is too high this is detected by the brain and the control centre on receiving this signal will tell the thyroid gland not to secret too much thyroid hormone ie a controlling hormone is produced by the brain to fine tune how much thyroid hormone is secreted by the thyroid gland eg if thyroid hormone is too high in the blood this is detected by the brain less controlling hormone is sent out from the control centre there is thus less stimulation on the thyroid gland resulting in less thyroid hormone secreted maintaining a balance now coming the the main question : what is the use of thyroid hormone in the human body? thyroid hormone is meant to control our metabolism did you get it? probably not. What is meant my metabolism? I reckon most people cannot answer this question you may have heard of the word metabolism for many times but still not knowing what exactly does it mean actually it's simple: metabolism refers to the process by which food is converted to energy to be used by the human body let me repeat metabolism is the process through which food is converted to energy it's just that simple if you understand this then it is easy to understand the diseases affecting the thyroid gland let's talk about hyperthyroidism or we may call it overactive thyroid if there is too much thyroid hormone what will happen? if there is too much thyroid hormone circulation in the body the result is all the cells would have a faster metabolic rate because in all these cells the process by which food is converted into energy is sped up a lot of extra energy is generated thyroid hormone has effects on many systems eg it control the rate of heat production in the body human beings are warm blood animals unlike tortoise fish etc we have to constantly consume energy to general body heat eg in this room the temperature is 10 degree Celsius and the optimal body temperature is 37 degree Celsius the body must use up energy to generate heat to maintain this temperature thyroid hormone can tell certain fat cells in the body to generate heat to keep the body at 37C on the other hand thyroid hormone can affect bowel movement when you eat your intestine would move to push the food forward for digestion if your thyroid hormone is too high the body will generate too much heat therefore the classic symptom of an overactive thyroid gland is heat indolence ie always feeling hot and sweat a lot even though it is not really hot and people around him/her don't share the same feeling and if too much thyroid hormone is acting on the gut the muscle in the bowel will contract excessively the result is the food being digested passes through the bowel very quickly and the typical symptom of hyperthyroidism is diarrhea as far as the heart is concerned if metabolism of the cells controlling heart rate is fast as a result of an overactive thyroid you will have the classical symptom of hyperthyroidism: palpitations now let us switch to hypothyroidism or low thyroid hormone what will happen if there is too little thyroid hormone it is simple it is just the opposite of hyperthyroidism again let's start with body heat generation a lack of thyroid hormone leads to ineffective heat generation it follows that people with low thyroid hormone tends to feel cold even when the surrounding is warm and this can happen in hot summer and coming to the bowel peristalsis or movement of the bowel would become sluggish when thyroid hormone is low propulsion of digested food in the bowel will become slow leading to constipation a word about the heart hypothyroidism will lead to slowing of the heart because the metabolism of cells in the conduction system has a reduced metabolic rate let's talk about interpretation of thyroid function test if you look closely a thyroid function test consists of a number of items first you have TSH: thyroid stimulating hormone: the hormone secreted by the Brain which tell the thyroid gland to secret more thyroid hormone this TSH is very important thyroid hormone is also measured in a thyroid function test there are 2 types of thyroid hormone with a bit of difference between them the first one is called T3 the second is T4 the letter T refers to thyroxine and thyroxine is the technical term of thyroid hormone how T3 is different from T4? their molecular structure is slightly different if you are of my age you may recall parents ask children to eat more fish to absorb more iodine ; if not there will be goiter( a swollen thyroid gland) in other words iodine is important in the health of the thyroid gland in a T3 molecule there are 3 iodine atoms in the T4 molecule there are 4 this is the major difference between the 2 functionally speaking, notice that only T3 is the active hormone which can speed up metablism T4 is an inactive hormone which has no effect on metabolic rate in a more detailed thyroid function test you may seee 2 items called FT3 and FT4 what are FT3 and FT4? F means free why do you call a hormone free? what is freedom have anything to do with T3/T4? here is the thing for both T3 and T4 not all of them are free floating in the blood many of these hormone molecules are bound to serum protein protein bound hormone and free standing hormone are both found in the bloodstream thyroid hormone have to enter the cells to exert its function of speeding up metabolism this is only possible if the hormone is free standing in the blood this is because protein bound hormone are too bulky to enter a cell therefore it is obvious that it is the free thyroid hormone which is responsible for the control of metabolism therefore if you opt for a cheaper thyroid function test where only TOTAL T3/T4 are measured ie the lump sum of the amount of protein bound hormone and free hormone you cannot tell how much is free hormone and how much is bound hormone ie it gives you no information what proportion of the hormone is active because as I said only free hormone is active what we really want to know is the level of ACTIVE hormone it is always better to test for FT4 and FT3 if they are available yet even if you measure FT3/4 because they have a very wide normal range they are not a sensitive markets of the actual thyroid hormone status say for example if you begin to have an overactive thyroid gland FT3/4 may still be in the upper side of the normal range and you may not think there is a problem however even at this early stage if you choose to look at TSH ie thyroid stimulating hormone It is a much more sensitive indicators of the real thyroid status at the beginning of hyperthyroidism even if FT3/4 may be normal the level of TSH under the negative feedback from blood thyroid hormone the level of TSH will be suppressed to a lower than normal level therefore in clinical practice even though FT3/4 is normal but if TSH is low/high that still means you may have hyperthyroidism/hypothyroidism therefore of all the items in a thyroid function test TSH is the best indicator for thyroid function if you have any other questions about thyroid gland please leave your comments today the number of subscribers of my channel has exceeded 300000 thank you all for your support over the last 4 years I've never imagined amateur videos like mine would come a long way until today thank you again and I'd like to remind you that the 3rd edition of my new book is being published if you have not bought one please consider buying one from Cosmos bookstore, Eslite Joint Publishing, Chung Hwa Bookstore and HKTV mall and for overseas readers from now on you may order my book from the Hong Kong Book City website please go and have a look you can buy the book and have it posted to your country thanks for watching and I'll see you soon bye

Channel: Dr. Rex 醫學幼稚園

Views: 145,730

Keywords: dr. rex, 甲狀腺, 甲狀腺亢奮, 甲狀腺低, 甲狀腺功能, 驗血報告, thyroid, thyroid function test, t3, t4, TSH, 劉榮幹醫生, 醫學幼稚園

Id: yThn7Y_C3Gs

Length: 11min 29sec (689 seconds)

Published: Thu Mar 21 2024