0:09 all right ner so we talked about the
0:11 thyroid gland in super great detail we
0:13 covered things in so much detail that
0:15 what I wanted to do in this video was
0:17 just give us a nice little overview of
0:18 that entire video so let's go ahead and
0:20 Dive Right In so if you look here we're
0:22 going to start the hypothalamus so if
0:23 you remember in the hypothalamus there
0:26 was specific neurons right that were
0:30 actually releasing the specific chemical
0:31 and what was that chemical that they
0:34 were secreting that chemical was called
0:37 thyrotropin releasing hormone and if you
0:38 want the nucleus was called the par
0:41 ventricular nucleus right what was that
0:42 TR doing it was flowing through the
0:44 hypophysial portal system which was just
0:46 a vascular connection right here right
0:48 so here's a little vascular connection
0:50 it was flowing through that where down
0:53 into the anter pituitary and in the
0:55 anterior pituitary there was some
0:57 specific cells right there what were
0:58 these cells here called these were
1:01 called thyrotropes right and these
1:03 thyrotropes were responding to the TR
1:05 and what were they secreting they were
1:06 secreting what's
1:10 called thyroid stimulating hormone right
1:13 so the first step was TR Second Step was
1:16 TSH what's the next thing well now we
1:18 have the thyroid gland well what has to
1:20 happen is the thyroid stimulating
1:22 hormone is going to circulate down
1:24 through the blood to the thyroid gland
1:26 and then it's going to act on the
1:28 thyroid gland when it acts on the
1:29 thyroid gland if you remember we said
1:32 that the overall result of this was the
1:38 production of T3 and T4 which stands for
1:41 our thyroid hormone right and then we
1:42 said that it's transported in the
1:45 bloodstream through the thyroxine B
1:47 globulins right and exerts its effects
1:49 on various different Target organs which
1:50 we're going to talk about in a brief
1:52 second here what I want to do is so now
1:53 that we understand this what's called
1:58 hypothalamic pituitary thyroid axis
2:00 let's say something real quick about
2:01 what happens whenever you have too much
2:04 or too low how does this affect it so if
2:06 you think about it for a second let's
2:07 say that your TH levels are high your
2:09 thyroid hormone levels are high what
2:12 does that do so let's draw here in
2:15 red it can actually circulate back up to
2:17 the hypothalamus and exert what's called
2:20 a negative feedback mechanism what does
2:22 that mean it inhibits the
2:25 paraventricular nucleus from making TR
2:27 if you don't make a lot of TR what do
2:31 you not make a lot of TSH if the T TSH
2:33 levels drop do you make as much T3 and
2:37 T4 no okay so high T3 and T4 negative
2:41 feedback low TR low TSH and then as a
2:44 result low T3 and T4 what about the
2:47 opposite if you have low T3 and T4 what
2:49 is it going to do it's going to exert a
2:50 negative feedback mechanism on the
2:52 paraventricular nucleus cause excessive
2:56 amounts of TR produce excessive amounts
2:58 of TSH and then the high amounts of TSH
3:01 will stimulate the increase in T3 and T4
3:04 so simple as that all right now that
3:05 we've done that let's look at the
3:07 effects of T3 and T4 on these various
3:08 Target organs and like I said we've
3:09 already gone into all of them in great
3:11 detail so we're just going to get the
3:13 overall look what was its effects on
3:15 bone it just promotes normal bone growth
3:19 so it promotes normal bone
3:22 growth and
3:24 maturation so it helps with being able
3:26 to promote normal bone growth and
3:28 maturation guess what else it does it
3:30 promotes normal muscular system
3:33 development and function so it promotes normal
3:36 normal muscular
3:38 muscular
3:41 function and
3:44 development okay what about on just
3:46 normal body cells do you remember it
3:49 increased the basil metabolic rate by
3:51 increasing the sodium potassium ATP AC
3:53 so it increases your basil metabolic
3:56 rate it increases the oxygen
3:58 usage and then it actually can cause
4:00 more metabolism right what are some of
4:02 those metabolic pathways that it it does
4:05 so it can actually do what's called
4:07 lipolysis it can actually do what's called
4:09 called
4:11 glycolysis and it can even do another
4:15 process which is called glucon neo
4:17 genesis so it's actually a hyperglycemic
4:19 hormone right because it has the ability
4:21 to increase blood glucose levels via
4:23 gluconeogenesis and it can break down
4:25 substance because your basil metabolic
4:26 rat is increasing you want to break down
4:28 a lot of glucose so there's a lot of
4:31 glycolysis and helps to break down fat
4:33 oh one more that I want to mention here
4:34 which is really really important is
4:36 helps with what's called
4:40 LDL uptake so LDL is a cholesterol it's
4:42 called lipo density low density
4:44 lipoprotein and it actually is bad
4:46 cholesterol so if we what it helps to do
4:47 is get a lot of that bad cholesterol out
4:49 of the blood and into our liver cells
4:52 right so it helps to increase the LDL
4:54 uptake which helps to lower the actual
4:56 cholesterols within the
4:58 plasma okay so that's its effects there
4:59 what does it do on the Heart It promotes
5:07 normal
5:11 cardiac output right so cardiac output
5:13 and different types of other functions
5:15 right all right what about in the brain
5:18 it promotes normal nerve development so
5:19 it promotes the actual increase in the
5:21 synapsis so what does it do it increases the
5:32 myelination it increases the
5:34 dendrites so all of these things are
5:37 helping to do what increase the actual
5:38 nervous system development and function
5:40 so it helps to be able to promote these
5:42 activities what does it do on the GI
5:44 tract it promotes normal GI motility and
5:46 function so it promotes motility so
5:49 contractions so it promotes
5:56 motility and secretions of the GI
5:58 tract and then again what does it do to
6:00 the scan it promotes the normal
6:03 hydration of the skin so it promotes
6:05 promotes normal
6:07 normal
6:11 hydration of the skin okay so if we
6:12 understand this this is the basic
6:15 overall function of thyroid hormone so
6:17 what happens TR is regulating the
6:19 production of TSH by the anterior
6:21 pituitary TSH is acting on a thyroid
6:23 gland to produce thyroid hormone and
6:25 thyroid hormone can produce bone growth
6:27 and maturation normal muscular function
6:29 and development increase our basil
6:31 metabolic rate and oxygen usage and it
6:33 can undergo lipolysis mechanisms
6:35 glycolysis mechanisms gluconeogenic
6:37 mechanisms and it can increase the
6:41 uptake of ldls low deny Lio proteins
6:42 promotes normal cardiac output and
6:45 pumping functions increases the synapsis
6:47 and the myelination and the dendrites
6:50 within our central nervous system and it
6:51 helps to promote normal motility and
6:53 secretions of the gastrointestinal tract
6:56 and promotes normal hydration of the
6:59 skin tissue so in that in a n sh that
7:01 gives us the functions of thyroid
7:05 hormone and also again knowing what
7:06 happens when there's elevated levels of
7:08 thyroid hormone what does it do it works
7:11 through a negative feedback mechanism to
7:14 inhibit the paraventricular nucleus to
7:16 stop making TR but if the thyroid
7:18 hormone levels are low it'll work
7:19 through the negative feedback mechanism
7:21 to stimulate the pair of ventricular
7:25 nucleus to make TR and then more TSH and
7:28 then more thyroid hormone all right
7:29 engineer so this was an overview on the
7:31 thyroid hormone I hope this made sense
