The thyroid gland, despite its small size, plays a critical role in regulating metabolism and energy utilization, significantly impacting various bodily functions from energy levels and weight to cardiovascular health and even sexual function.
Mind Map
Cliquer pour agrandir
Cliquez pour explorer la carte mentale interactive complète
you have a small gland in your body that
weighs about 20 to 30 grams yet despite
its small size it has some of those
powerful effects over your metabolism
and how you utilize energy let me give
you an idea here when this gland isn't
secreting hormones in the proper amounts
your metabolism can fall as much as 40
to 50 percent below normal but on the
flip side if it's secreting too many of
the hormones metabolism can go up as
high as 60 to 100 above normal so
clearly this gland packs quite the punch
and the gland in question here is the
thyroid gland so in today's video we're
going to talk about how this gland
influences metabolism and how this
affects things like energy levels fat
weight gain and weight loss how it
affects your muscle tissue and even your
heart and can this thyroid gland
actually even affect sexual function
well we're about to find out so let's
jump right into this anatomical awesomeness
awesomeness [Music]
[Music]
so let's start by taking a look at a
real thyroid gland on this cadaver
dissection so if you take a look here
look how amazing this small little gland
here it's such a small gland to have
such powerful effects on the human body
you can see its proximity to the trachea
or the windpipe and we say that it's
inferior or below the atom's apple and
the Adam's apple is truly called the
larynx so this point right here that I'm
tapping with the probe is the same point
on me right there on my neck so
hopefully that gives you a pretty good
idea of where this gland would reside
now if we were to zoom in to the thyroid
gland tissue we would see that it's
primarily made up of these cells called
follicular cells and these follicular
cells are going to be what produces and
secretes the main thyroid hormones but
let's kind of take a step back for just
a second before we get into what these
thyroid hormones do and talk about what
actually activates this gland to do that
we're going to take a look at the brain
so here's A sagittal cut through the
head and we're definitely going to take
a look at some of the structures in the
central core here but first I want to
mention that we are going to play a
little bit of this game called telephone
and what I mean by that is that we're
going to find that a structure called
the hypothalamus is going to tell the
pituitary gland to tell the thyroid
gland to turn on or activate and we're
going to use an analogy or a little bit
of a comparison to help us with this and
some of you may have even actually lived
this comparison because sometimes dads
don't love it when people mess with
their thermostats and therefore the
overall temperature of the house so
we're going to say Dad tells the
thermostat to tell the furnace to turn
on or activate and hopefully that'll
help us more fully understand how the
thyroid gland gets activated here so
back to the central core of the brain
right where the probe is you're going to
see is the hypothalamus now the
hypothalamus the central core of the
brain does many amazing things one of
which has helped to maintain homeostasis
throughout the body and one of the
things that helps with this is to
regulate the thyroid gland so this
hypothalamus is going to secrete a
hormone called thyrotropin releasing
hormone or trh now as trh is going to
immediately diffuse into tiny little
capillars or blood vessels right around
the hypothalamus and travel down this
little nervous system stock in the blood
vessels here right to the pituitary
gland now that trh from the hypothalamus
is going to tell the pituitary gland to
secrete another hormone called thyroid
stimulating hormone or TSH that TSH is
also going to diffuse into surrounding
blood vessels and then circulate
throughout the body and eventually make
it to
the thyroid gland and that TSH from the
pituitary is going to tell the thyroid
gland to activate when we say activate
that means start secreting and producing
those main thyroid hormones so if we go
back to that analogy with the furnace we
would essentially say Dad the
hypothalamus secretes the trh to tell
the thermostat the pituitary gland to
secrete TSH
to then tell
the furnace
the thyroid gland to turn on and
activate and release its hormones which
is a pretty good analogy I think because
when the thyroid hormones start being
secreted increasing metabolism will also
increase body temperature furnace body
temperature it works now like I
mentioned when the thyroid gland is
turned on or activated it will secrete
the main thyroid hormones and these main
thyroid hormones have incredibly
powerful metabolic effects on multiple
structures and tissues throughout the
body now these main thyroid hormones are
called and I promise I'm not going to
give you too many more names throughout
this video but these main hormones are
called T3 and T4 T3 stands for
tri-iodothyronine and T4 stands for
Tetra iodothyronine so we're just going
to call them T3 and T4 but for those of
you who are interested try iodothyronine
that name comes from that the hormone
has three atoms of iodine where Tetra
iodothyronine that hormone has four
atoms of iodine so if you have an iodine
deficiency or if you don't have any
iodine you can't actually synthesize
these hormones and having an iodine
deficiency could cause all sorts of
thyroid related functional problems now
if a kid has an iodine deficiency that's
even a bigger deal because the thyroid
gland really gets involved in growth and
development throughout childhood so that
can cause delays in that development
those important developmental stages
throughout the beginning years of life
now luckily we only need about 50
milligrams of iodine per year to support
thyroid function and in most developed
countries the salt is iodized meaning it
just contains iodine so most of us don't
really have an issue getting the proper
amounts of iodine now another thing I do
want to mention kind of as an FYI
because I know I've mentioned a ton of
different names like thyrotropin
releasing hormone thyroid stimulating
hormone and now T3 and T4 if you wanted
to kind of simplify that and really
focus on it from say like a clinical
perspective like as a clinician with my
patients when I order thyroid tests for
them I usually just get a TSH to see
what the pituitary gland's doing and a
T4 to see what the thyroid gland is
doing and I'll kind of play a little
game with you guys at the end to kind of
show you how to analyze what's going on
with too much or too little of these
different thyroid hormones so we can
kind of figure out what's going on but
one thing we also need to cover here is
how these hormones are regulated but
real quick I want to take a second to
say thank you to a major supporter of
this Channel and that's the sponsor of
today's video athletic greens athletic
greens is a nutrition company that makes
an amazing nutritional drink called ag1
ag1 has become a major staple of my
morning routine and it is completely
replaced my daily vitamin and this is
much more than just a greens powder it's
packed with 75 different ingredients
including vitamins minerals probiotics
superfoods and adaptogens now my morning
routine needs to be quick and efficient
and this definitely fits into that
because all you have to do is take one
smooth tube dump it in eight ounces of
water Shake It Up and drink it down and
as an added bonus it tastes great which
can create problems with your family
trying to take it from you sometimes
without you knowing so you might just
have to get some for them as well now
there are many potential benefits from
taking ag1 one of my personal favorites
is that it can help boost and maintain
energy levels throughout the day so if
you're not a big coffee drinker like
myself or maybe you're trying to reduce
the amount of coffee or caffeine that
you take on a day-to-day basis ag1 could
supplement and even potentially replace
this to help boost those energy levels
now athletic greens that name is a
pretty great name in my mind because I
know many athletes and Weekend Warriors
like myself take ag1 to help boost
athletic performance as well as help to
recover as quickly as possible between
workouts ag-1 is also NSS certified
which is extremely important to me
because that means what's on the label
is actually going to be found within the
product again this is something that I
have really enjoyed taking each and
every morning so if you're interested in
trying this go to athleticgreens.com
human anatomy and they'll give our
audience a free one-year supply of
immune supporting vitamin D3 plus K2 as
well as five free travel packets with
your first purchase we'll also include
that information in the description
below so back to the regulation of these
thyroid hormones regulation of thyroid
hormones and just regulation of hormones
in general is very important and when I
talk about hormone regulation with
students and maybe you've heard me
mention this in previous videos with
hormone regulation we want the
Goldilocks principle and what I mean by
that is that we don't want too few of
the hormones not too many of them we
want them in just the right range
throughout the bloodstream and we can
use that thermostat and firmness analogy
again to help us with this let's say
that the house temperature is 69 degrees
and then Dad sets the thermostat to 70
degrees we all have a pretty good idea
that the thermostat is going to kick on
the furnace and tell what happens until
the temperature gets up to 70 degrees
and then it's going to shut off let's
apply that same information to the
thyroid hormones let's say the thyroid
hormone levels in the blood are a little
low the pituitary and the hypothalamus
will detect this and kick on the thyroid
gland to secrete more of those thyroid
hormones until they get up to the proper
levels and then it will shut off and so
this is a really awesome way to tightly
regulate these thyroid hormone levels so
you don't have a ton of fluctuations
because we all know that if we had a
really crappy heating system let's say
we set the temperature again to 70
degrees but the thermostat didn't kick
on the furnace until it was all the way
down to 50 degrees or the opposite end
of the spectrum it didn't shut off until
it was up to 80 or 90 degrees that would
not be a fun situation because the
temperature throughout the house would
be fluctuating like crazy but instead we
tightly regulate the house temperature
just like we would tightly regulate
those thyroid hormone levels so I think
we set the stage well enough now to
where we can finally start talking about
some of the specific functions of these
thyroid hormones now we've strongly
implied that the thyroid hormones helped
to regulate metabolism or in other words
help to increase metabolism but what
does that really mean and how should we
approach this well I think we should
start at the cellular level because if
we can figure out how these thyroid
hormones influence the metabolism of the
cells we can apply apply that to how the
cells process things like carbohydrates
and fats and even apply that to larger
structures like how does that affect
adipose or fatty tissue muscular tissue
and other tissues and structures
throughout the body and keep in mind
that your overall metabolic rate or your
basal metabolic rate is the totality of
the metabolism or how all the cells
throughout your body are processing
energy so looking at it from the
cellular standpoint or the cellular
perspective first kind of makes sense
and these thyroid hormones influence or
affect the majority of the cells
throughout the body and one of the
things that they do is help to activate
or turn on multiple genes and what we're
going to see is that the cell will start
building things it'll start building
things like protein enzymes structural
proteins transport proteins and other
substances and so if you look at it from
this perspective when the cell is
building all these different proteins
and other substances that's going to
require energy which will raise
metabolism of the cell if we take that a
little bit further
a lot of those proteins like the enzymes
and the transport proteins often require
energy to perform the work of the cell
that will also require energy and
therefore also increase the metabolism
of the cell another awesome thing that
the thyroid hormones do within the cell
is that they increase the size and
number of mitochondria and those of you
who know what the mitochondria is we
often nickname it the PowerHouse of the
cell because this little organelle helps
to utilize carbohydrates and lipids to
process ATP which is the energy currency
of the cell and if we're increasing the
metabolic rate of the cell we want more
ATP to support that increased metabolism
thyroid hormones have powerful effects
on carbohydrates it will increase the
rate at which cells bring in
carbohydrates it will also enhance
glycolysis which is when the cells take
glucose a type of carbohydrate and
utilize that to produce more ATP it also
enhances gluconeogenesis this primarily
happens in the liver and this is where
the liver produces more carbohydrates it
will also increase the rate at which the
carbohydrates are absorbed across the
gut and into the bloodstream so in
summary these thyroid hormones pretty
much stimulate or enhance almost all
aspects of carbohydrate metabolism not
only do these thyroid hormones help to
enhance the utilization of carbohydrates
they also help to enhance the
utilization of fats and what we'll see
is that the thyroid hormones will help
to pull fat from the fat storage in the
form of free fatty acids and these free
fatty acids can then circulate
throughout the blood and then be
utilized for energy by the cells now if
we're pulling fat from the fat storage
that will help facilitate weight loss or
at least help to maintain a healthy
weight when we have those normal levels
of the thyroid hormone now another cool
thing that the thyroid hormones do is
they will actually lower or bring down
cholesterol and triglyceride levels in
the blood and if you've ever had your
cholesterol tested you have a pretty
good idea that we don't want our
cholesterol levels to get too high so
let's have a little checkpoint here
because many of you are probably
thinking about the potential drawbacks
of having something called
hypothyroidism which is having too low
of the thyroid hormone and if we use one
of our previous examples if somebody
were too low with the thyroid hormones
their cholesterol levels could go up and
that could increase their risk of
certain cardiovascular conditions now
some of the obvious drawbacks is
metabolism is going to go down we're not
going to utilize carbohydrates as well
not going to utilize fats as well and
you'll often see weight gain with people
who have hypothyroidism now with many of
our students my patients and even in our
YouTube videos we often will talk about
diet and exercise and how much that can
influence weight gain or weight loss now
we definitely have some level of control
with weight gain and weight loss but
somebody who has hypothyroidism that
makes it even that much more difficult
to lose weight just with diet and
exercise so a lot of times when my
patients have a low level of thyroid
hormone they really like it when their
levels get to those normal ranges
because it makes it easier to shed some
of that weight now many people will
focus on the drawbacks of hypothyroidism
and they'll think just give me those
thyroid hormones increase my metabolism
and everything's going to be great but
remember the Goldilocks principle not
too few not too many just right there
are health conditions and drawbacks to
being hyperthyroid or having
hyperthyroidism and so it's not like
when somebody's hypothyroidism we just
jack up the thyroid levels to these
astronomical levels we get them to
within the normal ranges so as we go
throughout these other examples kind of
think of it from the perspective of okay
what would happen if I went too high
with the thyroid hormone versus if I
went too low the thyroid hormones also
have an effect on cardiovascular
structures as well as the heart due to
the increased metabolic activity many of
the blood vessels to the tissues will
vasodilate or open up delivering more
oxygen to accommodate that increased
metabolism as well as to be able to pull
waste products from the cells
metabolizing and creating those waste
products the heart will also contract
more forcefully as well as increase in
strength heart rate tends to go up with
thyroid hormone as well but again coming
back to our balance here if we had
hypothyroidism that would create less
contractility of the heart maybe
decreased strength also heart rate would
be lower if we had too much heart rate
would be too high and if you think of
somebody who had hyperthyroidism for
years and years and years and it wasn't
controlled eventually the heart can
start to break down the proteins within
The myocardium which is the heart muscle
will start to break down and you can
actually get things like myocardial
failure respiratory rate or breathing
rate will also increase with thyroid
hormones which makes sense to help
facilitate getting more oxygen into the
bloodstream to help accommodate the
increased metabolism we'll also see that
the gut motility how much the guts are
Contracting and moving food along
increases with thyroid hormone and so
somebody who actually has hypothyroidism
their gut motility will actually slow a
bit and things don't pass through as
quickly so they tend to actually get
constipated whereas somebody with
hyperthyroidism their guts are
Contracting more frequently and
forcefully and things are passing
through too quickly and they often will
get diarrhea thyroid hormones also
affect skeletal muscle tissues and with
slight increases of thyroid hormones
we'll see that the skeletal muscles will
contract a little bit more quickly and
vigorously but again with excessive
levels we we can have a problem with
hyperthyroidism because the skeletal
muscles can actually weaken due to
protein breakdown now with
hypothyroidism the muscles will actually
contract more sluggishly and react more
slowly and you're probably not going to
be surprised that thyroid hormones have
an effect on the nervous system and
normal levels of those thyroid hormones
have a positive effect on cerebral
function but excess amounts can cause
things like anxiety agitation kind of
feeling fidgety even some people have
experienced things like paranoia now if
they're too low or hypothyroid we can
get things like somnolence which is
feeling tired lethargic and just kind of
feeling blah and what about sexual
function of course the thyroid hormones
are also going to affect sexual function
so you're probably again not going to be
that surprised to hear me say we want
those hormones within the proper ranges
so that our genital structures in our
reproductive physiology works properly
now let's say a male has hypothyroidism
that could affect things or at least
cause decreased sex drive in libido
whereas hyperthyroidism could cause
impotence in a male impotence would be
an inability to get an erection with
females with hypothyroidism you could
also see a decrease in libido and sex
drive hyperthyroidism would tend to have
irregularities in the menstrual cycle
but you can also have irregularities in
the menstrual cycle with hypothyroidism
in females so looking at the menstrual
cycle alone is not a really good
indicator of hyper versus hypothyroidism
so hopefully that gave you a lot of cool
information on just how powerful the
thyroid gland in its hormones are and
how it affects multiple tissues and
structures throughout the human body now
as I mentioned earlier when I'm checking
for thyroid conditions on patients I
really focus just on two hormones when I
do a blood draw I usually draw the TSH
which is the thyroid stimulating hormone
released from the pituitary gland and I
really focus on the T4 which is one of
the main thyroid hormones secreted from
the actual thyroid gland now let me give
you a couple of scenarios to help you
kind of assess with these blood levels
like might mean let's say I have a
patient and I get the blood levels back
in the T4 from the thyroid gland is
really low but the TSH from the
pituitary is really high what that's
telling me is that we have a problem
with the thyroid gland because it's not
responding to the TSH telling it to turn
on and that would be called primary
hypothyroidism because we have the
problem with the thyroid itself let's
say in another scenario I have low T4
from the thyroid but also I have low TSH
from the pituitary gland that implies
that there's a problem with the
pituitary gland because the pituitary
gland isn't telling the thyroid gland to
actually turn on and do its thing the
thyroid's over here waiting like hey
pituitary I'm ready but the pituitary
isn't secreting the proper TSH to
activate the thyroid gland and that
would be called secondary hypothyroidism
let's go to another scenario let's say
the T4 from the thyroid gland is really
high but the TSH from the pituitary is
really low that would imply a problem
with the thyroid gland that the thyroid
gland is kind of Behaving on its own
without the TSH it's over secreting the
pituitary is like I'm not going to tell
you to turn on even more because we
already have too much of this thyroid
hormone that's almost like having your
thermostat set at 70 degrees for heat
but the temperature is already 85
Degrees your thermostat isn't going to
tell your furnace to kick on even more
in that scenario let me give you one
other scenario let's say the thyroid
gland or the T4 from the thyroid is
really high but the TSH is also very
high that's implying a problem with the
pituitary gland over secreting TSH and
then the thyroid gland is just following
suit being told what to do a lot of
times that's a pituitary tumor that's
secreting too much too much TSH that
scenario is kind of like you set the
thermostat in your house to 85 degrees
and the furnace is just kicking on to
obey the thermostat that so hopefully
that gives you some cool scenarios to
think about if you've ever got a thyroid
blood draw and hopefully you guys
learned some amazing things from this video
video
if you feel the need like always like
And subscribe leave some comments below
if you're interested in athletic greens
we'll also have that information in the
description below and of course we'll
see in the next video [Music]
Cliquez sur n'importe quel texte ou horodatage pour accéder directement à ce moment de la vidéo
Partager :
La plupart des transcriptions sont prêtes en moins de 5 secondes
Copie en un clicPlus de 125 languesRechercher dans le contenuAller aux horodatages
Collez une URL YouTube
Entrez le lien de n'importe quelle vidéo YouTube pour obtenir la transcription complète
Formulaire d'extraction de transcription
La plupart des transcriptions sont prêtes en moins de 5 secondes
Installez notre extension Chrome
Obtenez les transcriptions instantanément sans quitter YouTube. Installez notre extension Chrome et accédez en un clic à la transcription de n'importe quelle vidéo directement depuis la page de lecture.
