This content provides a concise overview of the adrenal gland's function, detailing its hormonal regulation, the specific hormones produced by its cortex and medulla, and their physiological effects, including a key negative feedback mechanism.
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All right, ninjaers. So, we talked in
great detail about the adrenal gland,
right? We went over in a lot a lot of
specific details. What I want to do now
is I just want to get a quick overview
of the adrenal gland. What stimulates
it? What's its target organs and some of
the negative feedback mechanisms? Okay.
All right. So, where do we have to
start? We have to start in the
hypothalamus. Now there's a specific
nucleus located in the hypothalamus and
again uh it's the the nucleus that's
actually going to be in this area. If I
were to draw here's the actual neuron
here. It secretes what hormone? This
hormone that it secretes is called
corticotropen releasing hormone. What's
the nucleus that actually secretes? This
is the par ventricular nucleus. What
does the corticotropen releasing hormone
do? It circulates down through the
hypoicial portal system and stimulates
specific cells located in the anterior
pituitary. Those are called
corticotropes. And when the
corticotropin releasing hormone
circulates down through the
hypoasoportal system and stimulates this
corticotrope, the corticotrope secretes
two different chemicals. One we're going
to focus on and one we're not going to
talk about. One is alpha MSH because we
talked about that in the large detailed
video. And then the important one which is
is
adreninocorticotropic hormone. All
right. So now what's the function of
adreninocorticotropic hormone. Okay.
Adreninocorticotropic hormone can go to
this adrenal gland here. Right? So the
adrenal gland has two components that we
talked about. If you look at these blue
cells, these red cells and these green
cells. All of these three layers make up
what's called the adrenal cortex. And in
the middle of the adrenal gland is going
to be the adrenal medulla. So what does
adrenalcorticotropic hormone do? Let's
follow it to the adrenal cortex. So it
comes over here, circulates through the
blood and it acts on a bunch of
different receptors on these cells,
right? So let's go ahead and remember
these basic cells here. What was this
blue cell layer here called? This blue
cell layer here was called the zona
glomemeilosa. This red cell layer here
is called the zona
faciculada. And this green cell layer
here is going to be the zona
zona
reticularis. What the
adreninocorticotropic hormone does is is
it can act on all of these three cells.
So let's show that here. Look, it's
coming in here and it bifurcates and it
can act on these three cells. So it can
stimulate the zona reticularis. It can
stimulate the zonop facicula and it can
stimulate the zona glmeilosa. Now there
is other stimuli here. We'll talk about
that in just a second. What is the zonog
glomemeillosa responsible for
secretreting? It secretes chemicals and
these chemicals are controlling your
mineral balance. So they're called
mineral corticoids, right? What was the
main one that we talked about?
Aldoststerone, right? And we'll talk
about him in just a second and his
effects. Then what else? Acetal I'm
sorry adrenalcorticotropic hormone can
act on the zonop faciciculata and it can
stimulate the zonopiculata to control
certain types of metabolic activities
with respect to glucose right and these
gluccocorticoids. Now the specific one
that we talked about is
cortisol. Okay. And then it can also the
adrenal corticotropic hormone can
stimulate the zona reticularis to
produce things that are risk going to
affect your gonads of the ovaries and
the testes and these are called
gonadoc corticoids. Now we talked about
these already. We're just going to call
them androgens, right? But the specific
ones were androone dione and DHEA
dehydroepiendostrone. Okay, now that
we've done that, what is some other
stimuli here for the zona glomemeillosa?
Because I want to talk about him too.
It's not just the adrenal corticotropic
hormone because he was one of the big
ones, right? So again, what hormone is
stimulating this process here? We were
to follow it out here. It's the adrenal
corticoot tropic hormone, right? What is
it doing? It's acting on these zonos,
zona facicula and zon reticularis.
There's other signals here. What is
these other signals here? Other things
could be for the zona glomemeilosa could
be angio tensin 2. What is another
signal here? It could be low plasma
sodium ions and high potassium ions in
the plasma. Right? And this is
stimulatory. This is stimulatory. But
they can also receive another signal
here. It's not significant. It's from
atrial nectaratic peptide and it's
inhibitory. Now angotensin 2, we talked
about him already. He's important for
being able to increase your blood
pressure. These sodium ions are helping
to stimulate the production of
aldoststerone and atriatriotic peptide
is trying to inhibit the production of
eldoststerone and adreninocorticotropic
hormone can have an effect on the
zonoglossa to produce aldoststerone. All
right. So, we've made all of these
different types of sex hormones, uh,
gluccocorticoids and mineral corticoids.
One more thing is the adrenal medulla.
So, if you look here in the adrenal
medulla, we already talked about him.
He's actually made up of nervous tissue,
right? So, neural tissue. So, he has the
post gangleionic motor neurons in here.
And when it's stimulated stimulated by
the sympathetic nervous system, right,
through the thoracco lumbar output, it
can secrete what? What are the chemicals
it secretes? Epinephrine and
norepinephrine. And we talked about
these in great detail, right? They help
to be able to stimulate
gluconneogenesis, glycogenolyis, and
lipolysis, right? And increase your
blood pressure. Okay? So, what are these
guys' effects in whole? increase BP increase
increase uh
uh glyco
genois and they increase what's called gluco
neoenesis and they increase what's called
called
lipolysis. Okay, now we've done these
guys. What's the effect of mineral
corticoids? Let's look at it over here.
So what was that hormone that we talked about?
about?
Aldoststerone. He affects the kidney
specifically in the distal convoluted
tubule, right? And what's his overall
function? He helps to be able to create
sodium reabsorption. So pull sodium from
the kidney tubules into the blood,
right? And then he excretes out
potassium. But as a result of the sodium
moving in, who else follows? Water. So
what's the overall result here? you
increase blood volume and you increase
blood pressure. Okay? And you also
increase the sodium content. All right?
So you end up what's called hyper
hyper
nitreia. Okay? But this could you know
not necessarily
pathological. Okay. What was the other
thing over here? It was with respect to
cortisol. So here's our cortisol over
here. Right? So cortisol did a lot of
things. What did it do? It act on the
white blood cells, your immune system.
What does it do to the immune system? It
suppresses the immune system, right? By
inhibiting the release of a lot of different
different
cytoines. So, it suppresses the immune
system. What does it do to the muscles?
You remember it's actually a very very
chronic stress hormone, right? So, it
can assist in what's called protein
protein
catabolism. So, it can break down
proteins into amino acids. What can it
do here to the fat tissue? It can cause
the fat tissue to
undergo lipolysis, right? So, it breaks
down triglycerides into fatty acids and
glycerol. And it can stimulate the liver
to do what's called a very very
important process and that process is called
called gluco
neoenesis. Okay? Okay, so it can take
amino acids and convert amino acids into
glucose. It can take glycerol and
convert it into glucose. Tons of
different things here, right? And it can
also enhance the sympathetic nervous
systems effects, right? By increasing
the adinuric receptors. All right, so
that's cortisol. All right, so we talked about
about
cortisol, we talked about asterostrone,
we talked about epinephrine and nor
epinephrine. Let's finish up with these
gonatorticoids. They're nothing that
we're going to spend a lot of time on.
And the reason why is they're so
insignificant. They're very very weak. I
should actually put here very
weak. But what they do is they can these
androgens can act as precursors. So if
for example, if I wanted to go to the
female, it could be used to make
estrogen. If I take it to the male, the
male can use that to make it into testosterone.
testosterone.
But their overall functions of the
gonatocorticoids primarily if we were to
just kind of overly their entire
function is to control libido. So sex
drive. Okay. All right. So now now that
we know that we understand what cortisol
does, eldoststerone does and
gonadocorticoid does. Now real quickly
here with the cortisol, this is the one
I really want to talk about. If you're
making because what happens
adreninocorticotropic hormone stimulates
your zonopiculata to make cortisol. What
happens if your cortisol levels rise
really really high? They exert a
negative feedback mechanism. So let's
say here's our cortisol. It exhibits a
negative feedback mechanism. What do you
do? You make less corticotropen
releasing hormone. You make less
adreninocorticotropic hormone and then
that triggers the the zonopiculata to
not make as much cortisol. That's that
negative feedback mechanism. Now, if it
was the exact opposite, if there's less
cortisol, there's going to be less
inhibitory input, right? So, there's
going to be less of that negative
feedback mechanism there. It's going to
cause them to make what? More
corticotropen releasing hormone. More
corticotropin releasing hormone will
actually stimulate the antipituitary
gland to make more act. And more ACT
will stimulate the zonal physiculata to
make more cortisol. All right guys, so I
hope that made sense. In this video, we
covered a general overview of all the
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