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AnatomyEndocrine — Transcript

by Dr. Naveen Jalota, M.D. · 11,366 words · 2,015 segments · language en · Watch on YouTube

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0:01Hello and welcome.
0:03Let's discuss today
0:08endocrine system.
0:17So, let's discuss endocrine system.
0:19Now, when we go through and we discuss
0:21endocrine system,
0:24very good. Not a centric ring system.
0:28So, here when we go through and we
0:29discuss endocrine system, this is
0:31covering chapter 18 in this book here.
0:34Now, when we go through and we talk
0:35introduction to the endocrine system,
0:38first here let's go through and let's
0:39talk a couple of terms that I'd like you
0:41to be familiar with. And the first term
0:43here is endocrinology.
0:46Now, when we go through and we talk
0:48endocrinology, endocrinology is going to
0:50be
0:51the study of hormones.
0:54It will be the study of hormones
0:58and endocrine organs. So, it's the study
1:01of hormones and endocrine organs.
1:06Now, when we go through and we talk
1:09function of this endocrine system, we'll
1:12see the function of this endocrine
1:14system is to influence the metabolic
1:18activity.
1:19It is to influence the metabolic
1:21activity
1:23of the body
1:27via hormones. It's to influence the
1:31metabolic activity of the body by means
1:35of hormones, via hormones.
1:41Next is the method of control. How does
1:45this endocrine system control the
1:47metabolism? It does this via the
1:48endocrine glands, one of those
1:50components. And we talk endocrine
1:51glands, I'd like you to know endocrine
1:54glands are ductless glands.
1:58Endocrine glands
2:01are ductless glands.
2:06Endocrine glands produce hormones. They
2:09produce hormones
2:13and they release these hormones that
2:15they produce
2:17into
2:18the surrounding
2:20tissue fluid.
2:28So, endocrine glands
2:30will secrete hormones into the
2:33surrounding tissue fluid.
2:35From there, it'll make its way, the
2:36hormone, well, into the bloodstream and
2:39travel
2:41to wherever it needs to go.
2:47I keep using the term hormones. You must
2:49be thinking what is this thing he keeps
2:52mentioning, hormones. Hormones are going
2:54to be chemical substances. They are
2:56chemical substances.
2:59You can think of them as messengers that
3:02are secreted into the bloodstream.
3:07So, chemical messengers, chemical
3:09substances that are secreted by certain
3:12cells
3:13that are secreted by certain cells into,
3:16we said, the surrounding tissue
3:20and eventually making their way into the
3:22bloodstream
3:25or even the lymph
3:28to travel to distant regions.
3:34So, chemical substances that are
3:36secreted by certain cells into the
3:39surrounding tissue, eventually making
3:41their way into the blood or the lymph.
3:43Most commonly, blood is what we'll check
3:44out and we'll talk
3:46to travel to distant
3:49organs
3:54to influence
3:55the metabolic function of other cells in
3:58the body.
4:04We compare and we contrast
4:07endocrine organs and endocrine glands to
4:11exocrine glands.
4:13Now, when we talk exocrine glands, we
4:14have talked about exocrine glands
4:16before, and so you make sure you've got
4:19the difference down now between exocrine
4:21glands and endocrine glands. Right? We
4:23said first they're ductless
4:25when we talk endocrine glands.
4:27And they secrete internally.
4:29We saw the exact opposite with exocrine
4:32glands.
4:34Now, when we go through and we talk
4:36endocrine system, endocrine glands,
4:39endocrine organs, this system
4:42is going to be compared to the nervous
4:43system. The reason why these two systems
4:45are compared to one another is because
4:47endocrine system, when it elicits an
4:49effect, well, first of all, the reason
4:51why they're compared is because they
4:52both control other systems. Right?
4:55Nervous system controls, we've seen
4:57muscular system. Okay? Here you can see
4:59this endocrine system is going to
5:00control a lot of other activities in the
5:02body. So, number one, endocrine systems
5:05effects tend to be slower.
5:07And they are more sustained compared to
5:09nervous system. Right? Nervous system,
5:11look how fast
5:12those reactions are. And they're not as
5:14sustained.
5:15Now, endocrine messengers, they can
5:18affect a wider variety of more distant
5:21organs. Right? There we had just our
5:26effector organs we described.
5:29Now, these two systems, not only are
5:30they compared to one another, but they
5:32also coordinate responses.
5:37And when they coordinate responses,
5:39this helps to again keep the body in
5:41homeostasis.
5:44Now, we have some cells in the body that
5:46are going to be referred to as
5:47neuroendocrine cells. The reason why is
5:50because they're going to have dual
5:51function. Not only are they going to be
5:52functioning for the nervous system,
5:54doing their tasks there, but they're
5:56also going to have a job here when it
5:57comes to endocrine system as well.
5:59So, neuroendocrine cells, which make up
6:02neuroendocrine organs, we can say there
6:04as well. We'll see a lot of organs are
6:06going to have dual function. Here we're
6:08saying neuro. Okay? The stomach is going
6:10to be releasing hormones, it also has
6:11another job. Same thing with the gonads.
6:14Same thing with the thymus. Same thing
6:16with lots of other organs we'll go
6:17through and we'll check out and we'll
6:18see here when it comes to the endocrine
6:21system.
6:23So, we talk means of travel. Means of
6:25travel. How do hormones travel? We said
6:27hormones are going to travel through the
6:28bloodstream.
6:30They will travel through the
6:31bloodstream.
6:34Now, when we talk target cells,
6:36target cells.
6:38Now, when we talk target cells, target
6:39cells are going to be the cells on which
6:42these hormones elicit their effect.
6:46They're the cells on which these
6:47hormones will elicit their effects.
6:51The target cells
6:53are capable of responding to hormones
6:57because they bear receptors
7:00for the hormone.
7:03It's like saying we all have keys.
7:07However, my key doesn't open your locks.
7:10Your keys don't open my locks.
7:12Or we have garage door openers.
7:14Right?
7:16Or even key fobs. Right? We all have
7:19them. However, they're all doing
7:20different tasks.
7:23So, target cells
7:24are going to be the cells on which the
7:26hormones will elicit their effects. So,
7:28the hormone can't just go and elicit an
7:30effect on any and every single cell.
7:32Right? Same thing with your key. Just
7:33because you have a key, you can't say,
7:34"Oh, I'm just going to go and open up,
7:35you know, my neighbor's door and I'm
7:36going to go inside their house." Well,
7:37you have a key, however, is that key the
7:40right key that's required to open up
7:42that lock? So, the same thing here when
7:43it comes to hormones. You can't say,
7:45"Oh, growth hormone is going to make its
7:47way over to where thyroid stimulating
7:49hormone works and it'll just cause an
7:51effect what TSH was supposed to be
7:53doing." That's not how it goes. Okay?
7:55So, there's target cells there. You got
7:57to make sure you remember that.
7:59Now, the speed of control. Very
8:01important here. When we talk speed of
8:02control, we'll see when we go through
8:04and we classify our hormones, our
8:05hormones are going to get classified
8:06into two main categories. They'll be
8:08classified into being either
8:10water soluble hormones or into being
8:12lipid soluble hormones. So, when we talk
8:14speed of control, you'll see some
8:16hormones have the ability to provoke
8:18target organ responses almost
8:20immediately.
8:23Others, like steroid hormones,
8:27they require hours
8:29or even days sometimes to elicit their
8:31effects.
8:34The water soluble hormones are going to
8:36work a little bit faster.
8:38So, we talk speed of control, that will
8:40all depend on which hormone we're
8:42talking about.
8:47Here you can appreciate all the organs
8:50that make up this endocrine gland that
8:52make up the endocrine system. So,
8:55they're all endocrine glands. Now, this
8:57system is also a little bit different
8:58compared to other systems. This system,
9:00you see the organs, they're all spread
9:01around everywhere throughout the body.
9:04When we talk gastrointestinal,
9:05gastrointestinal, we'll see they're
9:06going to be confined to a certain area.
9:08You're not going to find
9:09you know, those components in different
9:11parts. So, same thing reproductive,
9:13you're going to find in just one area.
9:15Okay? So, you can see how everything is
9:16going to be classified into their
9:18specific regions. But with endocrine
9:20system, you see these organs are going
9:22to be found scattered over the entire
9:23body.
9:26Now, when we go through and we talk
9:27about endocrine organs, here you can see
9:29various organs. Here they're showing us
9:31the pineal gland. When we zoom in on
9:32this area here, here we can appreciate
9:34the hypothalamus and we have the
9:35pituitary gland. And then down here we
9:37have the thyroid gland. And on the
9:39dorsal aspect of the thyroid gland, you
9:40can appreciate the parathyroid glands
9:42there. And then down here you can
9:43appreciate a few glands we're going to
9:45get into. And then moving down to the
9:47gonads. Male testes, females we're
9:51talking ovaries when we use the term
9:52gonads. So, that's why they're depicting
9:54both here. All a part of
9:56endocrine system because also have
9:58endocrine functions there as well. Very
10:00good.
10:03Next in here you can see all of these
10:04various organs again. Nice picture here
10:07depicting to us all the various organs.
10:09So, like we mentioned, some of these
10:11organs are going to be pure endocrine
10:13organs, while others are going to have
10:14dual functions. So, here you can see
10:16some of them as well.
10:24So, here let's go through and actually
10:26let's talk about each of these endocrine
10:27glands then. Now, when we go through and
10:29we talk each endocrine gland, the first
10:31gland I'd like you to know about and I'd
10:32like to mention is going to be our
10:34pituitary gland. Now, this pituitary
10:36gland is also known as the hypophysis.
10:38AKA hypophysis. It's a very tiny gland.
10:43It secretes about nine hormones we're
10:45going to go through and we're going to
10:46check out. It will secrete nine hormones
10:48we're going to go through and we're
10:49going to check out. This gland is going
10:51to get divided up into two lobes. So, it
10:53becomes it's considered to be bilobed.
10:57It's considered bilobed. Now, let's talk
10:59location. Location, you'll see it's
11:01securely seated. This gland is securely
11:04seated
11:05in
11:06the sella turcica
11:08of the sphenoid bone. In the sella
11:10turcica of the sphenoid bone.
11:12Now, when we go through we said we
11:14divide this gland up into two lobes.
11:16That's one way we could see there, but
11:18we'll move ahead and we'll see kind of
11:19how that happens further as well. This
11:22slide here is depicting to you how your
11:24steroid hormones will function. The
11:26reason why they take a little bit longer
11:28to function is because their receptors
11:29are found located inside the cell. So,
11:31here you could see that hormone actually
11:34has to penetrate the cell, make its way
11:36into the cell, and then look for that
11:38receptor and bind to the receptor. And
11:40when you have that receptor and hormone
11:42bound to one another, you form this
11:43receptor hormone complex. So, here then
11:46you can see that receptor hormone
11:48complex makes its way into the cell and
11:49can even initiate protein synthesis as
11:51we see taking place right inside of
11:53here. So, we're talking water soluble,
11:55water soluble, their receptors are going
11:57to be found located right on the
11:59membrane.
12:00So, here they're inside of the cell when
12:03it comes to lipid soluble hormones.
12:06Very important you understand that, too.
12:10So, here we can see that pituitary
12:12gland, two divisions we've got there.
12:14Now, here when we go through and we
12:15check out the two divisions, here we can
12:17appreciate both of them there very
12:20nicely.
12:22So, here we can see how this gland is
12:24divided up into two different lobes. And
12:26as we continue forward, we'll be able to
12:28appreciate the same thing through these
12:30images here as well. So, here you can
12:32see they're depicting the anterior and
12:34the posterior.
12:35Let's go through
12:38and let's check out first
12:41Let's do the anterior pituitary. Let's
12:43do the anterior pituitary. Now, we talk
12:45the anterior pituitary gland, the
12:47pituitary gland in itself I told you is
12:49going to be known as the hypophysis, the
12:51hypophysis.
12:52So, let's talk
12:54anterior pituitary. Now, we talk
12:55anterior pituitary gland, the anterior
12:57pituitary gland we are talking now about
12:59what we refer to as the adenohypophysis,
13:02the adenohypophysis.
13:04Now, when we talk adenohypophysis, the
13:06adenohypophysis of the anterior
13:08pituitary gland is composed of glandular
13:10tissue. It is composed of glandular
13:12tissue. And this to this gland, the
13:15adenohypophysis, it's going to
13:17manufacture and it's going to release a
13:19number of hormones. We're going to go
13:21through each and every one of them and
13:22we'll check them all out.
13:23This gland is under the control of the
13:27hypothalamus.
13:28The hypothalamus is going to be
13:30responsible for releasing, releasing,
13:33and inhibiting hormones.
13:35So, here when these releasing or
13:39inhibiting hormones are going to be
13:40released into the bloodstream, they're
13:42going to make their way over to the
13:43anterior pituitary to where they can
13:44either stimulate or they're going to
13:46inhibit those hormones from being
13:48secreted.
13:51So, it's important you understand
13:53each and every hypothalamic hormone that
13:55you have there and how it will control
13:59the anterior pituitary.
14:01So, first hormone we're going to talk
14:03about is going to be growth hormone. We
14:05talk about growth hormone, growth
14:06hormone is also abbreviated GH.
14:11Growth hormone is produced by the cells
14:15that are called the somatotrophs.
14:19So, growth hormone is produced by the
14:21somatotrophs of the anterior pituitary.
14:25The target organs, you'll see the major
14:28targets are going to be the bone and
14:31skeletal muscle. Will be the bone and
14:33skeletal muscle. These are the major
14:35organs like I said. However, we're going
14:36to see they can affect this hormone can
14:38affect a lot of different
14:40organs as well. We'll go through and
14:41we'll check all that out. The function
14:43now, the function of growth hormone is
14:45to stimulate your body's cells to
14:49increase in size and divide.
14:53It stimulates your body's cells
14:57to increase in size and divide. Growth
14:59promoting and you can say metabolic
15:02actions.
15:04It's got growth promoting and metabolic
15:06actions.
15:08So, here when we go through and we check
15:09out how growth hormone functions, you
15:12can see that here very nicely. So, you
15:15need to understand this thoroughly and
15:17you need to understand how growth
15:18hormone gets released by the anterior
15:22pituitary in response to growth hormone
15:25releasing hormone, which came from the
15:27anterior pituitary uh which came from
15:29And you also have growth hormone
15:30inhibiting hormone there as well.
15:33So, when we talk growth hormone
15:34inhibiting hormone, it's going to do
15:35exactly what its name says. It'll
15:36inhibit the release of growth hormone.
15:39So, when growth hormone is released,
15:40growth hormone is going to affect lots
15:43of different organs you can see here.
15:46Now, on our fat and carbohydrates, it's
15:49going to have a direct action. It will
15:52have a direct action where it will
15:55increase fat breakdown and release.
15:58With fat and non-carbohydrates, it's
16:01involved with carbohydrate metabolism.
16:03Here what it does is it's going to
16:04increase blood glucose and other
16:06anti-insulin effects. Now, when we talk
16:09liver and other tissues, now liver and
16:10other tissues it's not going to have a
16:11direct action like we saw with the
16:14indirect actions if with growth hormone
16:15there. Now, here it's going to produce
16:19insulin-like growth factors when it
16:21makes its way over to certain organs
16:23like the liver and other tissues. So, it
16:25makes its way over to those organs,
16:27those tissues, and it knocks on the door
16:28basically saying, "Hey, I'm here." And
16:30now what happens is those organs and
16:32those tissues are going to produce IGFs,
16:36insulin-like growth factors. These IGFs,
16:38insulin-like growth factors, now are
16:40going to have effects of their own. And
16:42here then you can see their effects that
16:45you'll be responsible for knowing about
16:46there as well.
16:50Now, too much or too little growth
16:51hormone.
16:53Too little,
16:54we have then
16:56what we call pituitary dwarfism.
16:59Too much,
17:01too much in the child before the growth
17:03plates close,
17:05patient can suffer from
17:07gigantism.
17:09If you have too much growth hormone
17:12before growth plates close, gigantism.
17:14Here the patient's going to have linear
17:15growth. They're usually taller like NBA
17:17players.
17:18Now, in uh
17:20acromegaly now, in acromegaly the growth
17:23hormone surge occurs after these growth
17:26plates have closed. And so there you
17:28don't see a linear growth, you have a
17:31widening
17:32of these various skeletal structures.
17:35So, these patients will come in
17:36complaining of their hat not fitting
17:38anymore, their shoes not fitting
17:39anymore.
17:41And then what you'll do to diagnose it
17:43is you'll ask them for pictures from
17:45previous years
17:48and try to compare the two and look at
17:50and they're usually in their
17:52late you know, maybe
17:5440s, 50s, even 30s. And so, you'll
17:57compare
17:58you know, the different decades
18:00and try to understand what you have
18:02going on there.
18:05And then there you have a female of
18:06normal stature, normal height.
18:10Next in here we can move on and we can
18:12move on and here we're going to be able
18:14to see our next hormone. Our next
18:16hormone is thyroid stimulating hormone,
18:18TSH,
18:20thyroid stimulating hormone. TSH also
18:23known as thyrotropin, also known as
18:26thyrotropin.
18:30So, here we've got TSH under the control
18:33of TRH coming from the hypothalamus.
18:36You've got right inside of there.
18:38Thyrotropin releasing hormone. Very
18:39good.
18:41So, we talk TSH also known as
18:43thyrotropin.
18:46Thyro-
18:48tropin.
18:51Now, organs, target organs.
18:54Now,
18:55TSH, TSH is going to target
18:59our thyrotrophs.
19:01It will target the thyrotrophs
19:08of our thyroid gland. It will target the
19:11thyrotrophs of our thyroid gland.
19:16All right, so coming back here. So, TRH,
19:20okay, let's clarify this. TRH is going
19:22to make its way from the hypothalamus
19:23making its way over to the anterior
19:24pituitary. So, it's going to stimulate
19:26the thyrotrophs of the anterior
19:29pituitary.
19:30It'll stimulate the thyrotrophs of the
19:31anterior pituitary to release TSH. TSH
19:36then is going to make its way over to
19:38the thyroid gland. And then we'll see
19:40what it does at the level of the thyroid
19:41gland. It's going to stimulate the
19:43normal secretory activity of the thyroid
19:45gland. So, thyrotrophs are going to be
19:47cells of our anterior pituitary.
19:52Now, when talk function, the function of
19:55TSH, again, is to stimulate the normal
19:58development and secretory activity of
19:59our thyroid gland.
20:02Of our thyroid gland.
20:05Next thing we have ACTH,
20:06adrenocorticotropic hormone, ACTH,
20:10aka corticotropin.
20:13Corticotropin. Now, ACTH is going to get
20:16released in response to
20:18CRH, which is coming from the
20:19hypothalamus. So, CRH
20:23makes its way
20:24over to
20:27the corticotrophs.
20:29Makes its way over to the corticotrophs,
20:31stimulates the corticotrophs
20:33of the anterior pituitary to release
20:35then ACTH.
20:37ACTH
20:39is going to target the adrenal glands.
20:41More specifically speaking, it will
20:42target the cortex of the adrenal glands,
20:45and even more specifically speaking,
20:47we'll see exactly which part of the
20:48cortex that it will target when we get
20:50to that gland itself.
20:53Now, when ACTH makes its way over to the
20:55gland, it's going to stimulate the
20:57adrenals to release
21:01corticosteroid hormone.
21:05Stimulates your adrenals to release
21:07corticosteroid hormone.
21:09Most important corticosteroid that
21:11you'll have to know about is going to be
21:13cortisol. It will be cortisol.
21:20Next thing we have our gonadotropins.
21:24Now, when we talk gonadotropins,
21:25gonadotropins will include
21:29FSH
21:31and LH. FSH and LH. FSH stands for
21:37follicle-stimulating hormone. LH stands
21:39for luteinizing
21:41hormone.
21:43Now,
21:44ACTH, we saw there under the control of
21:47CRH. Now, FSH and LH are gonadotropins
21:50are going to be under this
21:52hormone from the hypothalamus known as
21:54GnRH, gonadotropin-releasing
21:57hormone.
21:58So, when we talk gonadotropin-releasing
21:59hormone, gonadotropin-releasing hormone
22:02then is going to be responsible for
22:04releasing FSH and LH. Now, when we talk
22:06FSH, FSH, I'd like you to know it
22:09targets the ovaries and the testes. It
22:12will target the ovaries and the testes.
22:16Its function is to stimulate gamete
22:19production. Its function is to stimulate
22:22gamete production.
22:25Are you talking sperm or you're talking
22:26eggs?
22:30Next is luteinizing hormone. Luteinizing
22:32hormone, its target organs will include
22:35the ovaries and the testes. It will
22:37include the ovaries and the testes.
22:39And the function now of luteinizing
22:41hormone,
22:42its function will start with first in
22:43the males. In males, the function is to
22:46stimulate our interstitial cells. It
22:49functions to stimulate our interstitial
22:51cells in our testes
22:54so they can produce testosterone.
22:56So, in males,
23:02luteinizing hormone in males is
23:05responsible for stimulating
23:13It's responsible for stimulating
23:18So, when we go through and we talk about
23:21this hormone in males, again, you can
23:24see now luteinizing hormone is going to
23:26be again targeting the ovaries and the
23:28testes.
23:30And in the males, it's going to be
23:31stimulating the interstitial cells of
23:33the testes to produce testosterone. Now,
23:35in females, in females and women, it
23:37will trigger ovulation. It will trigger
23:40ovulation and it's going to help the
23:42ovarian follicles to mature, and it will
23:45help the ovarian follicles to mature.
23:49Next hormone we have then is prolactin.
23:51Prolactin. Now, when we talk prolactin,
23:53you can see prolactin is
23:56going to be controlled also by the
23:57hypothalamus. Now, prolactin is
24:00abbreviated PRL, you can see there, and
24:03it's a protein hormone that's
24:05structurally similar to growth hormone.
24:09And you'll see prolactin is controlled
24:11by an inhibiting hormone.
24:14It's controlled by an inhibiting
24:16hormone, and that inhibiting hormone is
24:18prolactin-inhibiting
24:20hormone, you see there from the
24:21hypothalamus, PIH, or dopamine, it's
24:25also known as.
24:26So, dopamine is increased, you'll see
24:28prolactin levels will be decreased.
24:31So, it's controlled by an inhibitory
24:33hormone,
24:34dopamine.
24:36And what is the function of prolactin?
24:38First, prolactin is going to target
24:41the breasts. It will target the
24:43secretory tissue of the breast.
24:46And its function is to stimulate milk
24:49production. Its function is to stimulate
24:52milk production.
24:55So, this helps us to then take care of
24:57this anterior pituitary. Now, here you
24:59can appreciate
25:01this superior hypophyseal artery here.
25:03This is the hypophyseal portal system.
25:06And again, here's the hypophyseal portal
25:08veins. So, here you can see these
25:10releasing hormones get released into the
25:12bloodstream. They take off, make their
25:14way into
25:16basically the bloodstream and on their
25:17way over to the anterior pituitary. So,
25:19from here then, you can see they'll take
25:21off like they're showing us into the
25:22blood, and from the blood, these
25:24hormones will go wherever they need to
25:25go like we described, and
25:28elicit their response there from these
25:30target cells.
25:33Next, let's move to the posterior
25:35pituitary now. So, anterior pituitary we
25:37took care of. Posterior pituitary now,
25:39we'll move back a couple of slides, is
25:42highlighted here. You can see very well
25:44now. When we talk about this posterior
25:46pituitary, this this posterior pituitary
25:48is also known as the neurohypophysis.
25:51Also known as the neurohypophysis.
25:54It's not a true endocrine gland.
25:57Basically, it's considered a storage
25:59unit, this posterior pituitary.
26:01And the reason why is because these
26:02hormones are going to be produced in the
26:04nuclei as we mentioned. That's why I
26:05told you you'll be responsible for
26:06knowing these various nuclei. You can
26:08see you got your paraventricular and
26:10supraoptic nuclei, and they're going to
26:11be responsible for then producing and
26:13then
26:14releasing these hormones. So, here we
26:17can see then we've got the axon
26:18terminals in that posterior pituitary,
26:20and then you can see you've got
26:22basically our blood vessels here. Here's
26:24the inferior hypophyseal artery, okay,
26:26compared to the superior we saw before,
26:29and you can see how then those hormones
26:31will get released into the bloodstream
26:33there. So, let's talk neurohypophysis.
26:35We talk posterior pituitary. First
26:37hormone that we have here is oxytocin.
26:39Oxytocin. We talk oxytocin, oxytocin is
26:43going to target the uterus and the
26:46breasts. So, its target organs are
26:48uterus and breasts.
26:50Now, the function. When we talk about
26:52the function, the function you'll see is
26:54to stimulate
26:56Oxytocin is responsible for stimulating
27:00uterine contractions.
27:03And it's involved with milk ejection
27:07from the breasts. And it's involved with
27:09milk ejection from the breasts.
27:13So, stimulates uterine contractions.
27:16Now, here what happens is the uterus,
27:18when the baby makes its way into the
27:20true, basically the pelvis, and is ready
27:23for delivery, as the baby moves
27:26positions, this gets that uterus to
27:28start to kind of expand, and then this
27:31is going to start sending signals to,
27:33you can see these nuclei to release
27:36oxytocin. Oxytocin makes its way out
27:38then, and oxytocin is going to stimulate
27:41uterine contractions. So, those
27:42contractions
27:44by the baby moving into the uterus, into
27:47this last segment of basically, you can
27:49see that uterus right before it's going
27:50to be making its way out. So, when it
27:52starts to change positions in there,
27:53this will get that uterus to start to
27:55contract and start to move, which
27:56stimulates oxytocin's release. Oxytocin
27:59is going to do what? Cause the uterus to
28:00contract. So, now when oxytocin gets
28:02released, it's going to cause the uterus
28:03to contract. When the uterus contracts,
28:05it causes oxytocin to be released. When
28:07oxytocin gets released, it causes the
28:08uterus to contract. And so, you can see
28:11this is going to continue. This is an
28:13example of a positive feedback
28:15mechanism.
28:17In a positive feedback mechanism, what
28:18happens is you can see you have a a
28:21waterfall type effect
28:23of the hormones.
28:26So, this hormone is going to keep
28:27getting released until when? Until the
28:30stimulus is no longer there.
28:32So, that's what happens in positive
28:33feedback mechanisms. So, now, how do we
28:36get rid of the stimulus? When the baby
28:37is
28:38basically born. When the baby is born,
28:40the uterus now is not going to contract.
28:42So, without it contracting, now we'll
28:45see that stimulus for oxytocin's levels
28:48to be increased aren't going to be as
28:50much as we would have with the baby
28:53causing that oxytocin to be increased.
28:56So, oxytocin is going to be responsible
28:57for milk ejection as well, right? Milk
28:59ejection. So, you can see the baby is
29:02basically born, and what's the first
29:04thing the baby's going to want besides
29:06the mom or, you know, the primary
29:08caregiver there? It's going to be milk.
29:14Next, then let's move. Let's move to
29:16antidiuretic hormone, ADH.
29:19Now, when we talk antidiuretic
29:21hormone, you'll see antidiuretic hormone
29:24will target the kidneys. The target
29:27organs are the kidneys.
29:29Now, here the function of antidiuretic
29:32hormone is to prevent wide swings.
29:38It is to prevent wide swings in our
29:42water balance.
29:45It's to prevent wide swings
29:48in our water balance.
29:50Helping the body to avoid dehydration
29:53and or water overload. Helps the body to
29:57avoid dehydration
30:00and or water overload.
30:03Antidiuretic
30:05hormone. So first let's talk the word
30:07diuretic. Diuretic is something that
30:09causes diuresis. What is diuresis?
30:12Diuresis is the removal of basically
30:14water from the body in the form of
30:15urine. So a diuretic,
30:18usually a drug, that is going to help
30:21remove water from the body.
30:24So here when we talk antidiuretic,
30:27so diuretic, I told you now antidiuretic
30:29is going to do the opposite. It won't
30:31allow fluids to be removed from the body
30:33in the form of urine.
30:36So it prevents wide swings in water
30:38balance, helping the body to avoid
30:40dehydration and water overload.
30:47Antidiuretic hormone.
30:50Now I'm just telling you right now here
30:51targets the kidneys, but but as we
30:53progress, you'll know exactly where in
30:55the kidneys it's going to be targeting.
30:57Or you could know that now here it's
30:59best to kind of go through that and get
31:00that taken care of here at this level as
31:02well.
31:05So ADH will prevent, again, wide swings
31:08in our water balance.
31:10It helps us to avoid dehydration and
31:12water overload.
31:14Let's move then from antidiuretic
31:17hormone. Let's move on to the thyroid
31:18gland. Now when we talk about the
31:20thyroid gland, I like you to know that
31:22the thyroid gland itself is a
31:24butterfly-shaped
31:26gland. It is a butterfly-shaped
31:28gland. This gland, the thyroid gland, is
31:31going to be found
31:33located in the anterior neck region. It
31:36is found located in the anterior neck
31:39region. And when we talk about this
31:42thyroid gland, it's basically made up of
31:45two lateral lobes. It's made up of two
31:49lateral lobes. Let's move over to the
31:51picture. Here you can see one picture
31:53where they're depicting that gland with
31:55other hormones being involved. But let's
31:57actually move to just that picture in
31:59itself. So here we could see very nicely
32:01same thing here very nicely, two lateral
32:04masses that are going to be connected by
32:06this median
32:08tissue. By this median tissue, it's
32:10called the isthmus. It is called the
32:13isthmus.
32:15This median tissue helps to connect the
32:18two lateral lobes.
32:20Next in here we've got what we call
32:24basically um
32:27the isthmus. So the isthmus is what we
32:29have there. You want to make sure you
32:29got that down there as well. So now here
32:32what we could see is we could see that
32:34gland in basically the macroscopic view.
32:39And we can see that gland then in a
32:41microscopic view here off to the side.
32:44Now here when we go through and we talk
32:46about this thyroid gland, this thyroid
32:47gland is found on the anterior neck on
32:50the trachea
32:52just inferior to the larynx. Just
32:56inferior to the larynx.
32:59So again, it's going to be found located
33:01in the anterior neck area just inferior
33:05to the larynx. Just inferior to the
33:07larynx.
33:10On the trachea. On the trachea. And you
33:11can see that here very well. Here's the
33:13larynx. You've got right inside of here.
33:15And here you can see
33:22So here we can appreciate the thyroid
33:24gland, again, macro and microscopically.
33:27Now here when we talk about this gland,
33:29this gland under the microscope, you can
33:32appreciate it here very nicely here on
33:34the right. And you can see this gland is
33:36made up of a whole bunch of different
33:38follicles. We've gone through, we've
33:39talked about these follicles before in
33:40the beginning of the semester when we
33:41talked about epithelial tissue.
33:44Now here we can appreciate each of these
33:45follicles. Now look at these individual
33:48follicles are made up from all these
33:51different follicular cells. So these are
33:54follicle cells that make up the
33:56follicle. I mean, I know how much easier
33:58we could make that there.
33:59Now each of these follicles
34:02has this colloid material inside. And
34:06that material is coming from these
34:08cells. These cells will make that stuff
34:10and basically accumulate it right inside
34:11of here. So let's go through and let's
34:13look at these follicle cells. These
34:14follicle cells can be cuboidal or even
34:17sometimes squamous
34:19in shape. They can be cuboidal to
34:22squamous in shape sometimes.
34:25These follicle cells are going to be
34:26responsible for producing thyroid
34:29hormones.
34:30Thyroid hormone. So here when we go
34:32through we talk thyroid hormones, these
34:33thyroid hormones are secreted by the
34:35thyroid follicles.
34:37Those hormones are made in the follicle
34:39by thyro- by thyroglobulin and iodine.
34:44They're made from thyroglobulin and
34:47iodine.
34:49Now when we go through and we'll talk
34:50about that whole process there as well
34:52and we'll check out that whole process
34:53of hormones being produced. Now the two
34:56thyroid hormones that you have to know
34:58about are going to include T3
35:02which stands for triiodothyronine.
35:09Triiodothyronine.
35:11Next we have T4. T4 stands for
35:14thyroxine.
35:19Now the target organs, the target organs
35:22for thyroid hormones, the target organs
35:26for thyroid hormones will include,
35:29you'll see they affect just about every
35:34single cell in the body. So when we go
35:36through and we talk about thyroid
35:37hormones, thyroid hormones are going to
35:38affect just about every cell in the
35:40body. Now what is the function of
35:42thyroid hormones? You'll see the
35:43function of thyroid hormones is to
35:45increase
35:47your basal metabolic rate. It's to
35:50increase your basal metabolic rate.
35:56To increase our basal metabolic rate.
35:59And also we'll see here
36:01so increasing basal metabolic rate
36:04body heat production body heat
36:07production.
36:09Thyroid hormone also helps to maintain
36:11blood pressure. Also involved with
36:13helping to maintain blood pressure.
36:17And it's responsible, you'll see, for
36:19regulating tissue growth. It's
36:22responsible for regulating tissue
36:24growth. It's responsible for regulating
36:27tissue development as well.
36:31Now when we talk skeleton nervous
36:33system, you'll see it's also involved
36:35with skeleton nervous system development
36:38and maturation.
36:40Thyroid hormone is involved in nervous
36:43system skeletal system development and
36:47maturation. And we'll see thyroid
36:49hormone is going to be responsible for
36:52reproductive capabilities as well. It's
36:54involved with reproductive capabilities.
36:59Now here we can appreciate the thyroid
37:01gland.
37:03And here you can see again
37:04microscopically and microscopically.
37:06So along with the follicular cells, we
37:08have here also C cells or you can refer
37:12to them as para, right? The prefix para
37:15means next to. Parafollicular cells. So
37:18the cells next to the follicular cells.
37:21Next in here we can appreciate the
37:23actual process of thyroid hormone
37:25formation. So here in this process of
37:27thyroid hormone formation, here you can
37:30see number one, iodide is going to be
37:33required. Without iodide, we're not
37:36going to be able to make functional
37:38thyroid hormones. So iodide comes
37:41through our diet. We get it from our
37:44salt, right? Our government has ensured
37:46that our salts have iodide in them.
37:48Along with the salt, we can also see
37:51iodide in
37:52shellfish, I believe it is as well.
37:55So here iodide comes in and iodide is
37:59going to get picked up and it is
38:01actively transported, right? Active
38:04transport, you should remember from
38:05biology. You've gone through active
38:07transport, you've seen that. So that's
38:08exactly what they're talking about here.
38:10Iodide gets actively transported. Now
38:13you can see into those thyroid follicle
38:17cells.
38:18Now within the cell then you can see
38:20iodide now move over to the opposite
38:23side.
38:24Moves over to the opposite side where it
38:27can exit now out of the cell and make
38:29its way then into the center of the
38:32follicle where the colloid is at.
38:35Now here as iodide passes through
38:38iodide, you can see here now becomes
38:42oxidized. When it becomes oxidized, it
38:44gives rise to iodine.
38:46Now at the same time here we have
38:49thyroglobulin being synthesized.
38:52Thyroglobulin protein, protein
38:54synthesis, right? You've seen all that.
38:56You should know this whole process
38:57through the rough ER, the Golgi
38:59apparatus, and then it gets packaged for
39:01basically modified packaged and and
39:04exocytosed. So here you could see
39:07thyroglobulin making its way out. Now
39:10thyroglobulin after having undergone all
39:12these different processes, thyroglobulin
39:14becomes tyrosine. So tyrosines are part
39:16of the thyroglobulin molecule. Now these
39:18tyrosine molecules that we have created
39:21are able to attach with iodine. Now when
39:24these molecules all start to come
39:26together, they form for us DIT or di
39:32because of two, diiodothyronine.
39:36And here we have monoiodothyronine.
39:39So the difference, one iodine
39:43attached to the tyrosines.
39:46So, here then you can see now when we
39:47get two DITs and we put them together,
39:50then we form
39:52T4.
39:53We get a DIT and one MIT and put them
39:57together, we have T3.
40:00So, you can see the difference between
40:01T3 and T4, one molecule iodine.
40:07Now, T3 and T4
40:09are going to get endocytosed. You can
40:11see here they make their way into the
40:13cell.
40:14And then from here, they're going to
40:17encounter lysosomes within the cell.
40:19Lysosomes now are going to
40:23basically come in and cleave T3 and T4.
40:26Once they come in and cleave T3 and T4,
40:28you can see here now at the opposite end
40:31of the cell now, we've got functional
40:34basically thyroid hormones here. These
40:35thyroid hormones now are going to make
40:37their way into the bloodstream and like
40:39we said, the rest is history.
40:43So, here we talk about increasing basal
40:46metabolic rate. We're talking increasing
40:47your metabolism.
40:49Right? When we talk metabolism, what are
40:51we talking about? We're talking about
40:52all the various chemical reactions that
40:55are taking place within our bodies. All
40:57the chemical reactions taking place
40:59within the body. So, increasing basal
41:01metabolic rate. Second then we said body
41:04heat production. If you look at the two,
41:05the two go hand in hand. Whenever we
41:07start having more chemical reactions
41:09take place, what's one byproduct of the
41:11chemical reaction?
41:13Heat production.
41:14So, heat production you can see is going
41:16to occur.
41:19Now,
41:20too much thyroid hormone. Too much
41:22thyroid hormone, we have increased
41:25metabolism. So, what's going to happen
41:27to the patient's size? Their
41:29patient will look a little bit
41:31overweight. Okay, but does that always
41:36stick with this
41:38hyperthyroidism here? No, because what's
41:40going to happen is once this patient's
41:41metabolism increases, this is going to
41:43cause them to become hungrier.
41:48Okay. So, let me go back. So, hyper if
41:51we have too much thyroid hormone. If we
41:53have too much thyroid hormone, we're
41:55going to have more chemical reactions
41:58taking place within the body.
42:00So, if we have hyperthyroidism, too much
42:02thyroid hormone, and normally speaking
42:04thyroid hormone is going to main
42:06basically it increases metabolism. So,
42:09if you have too much thyroid hormone,
42:11what's going to happen? This person's
42:12metabolism is going to be increased. So,
42:15when this metabolism increases, this is
42:17going to cause their figure to become
42:19thinner.
42:20They'll be skinnier.
42:22With too much with too much thyroid
42:24hormone, this will cause their
42:26metabolism to increase. With the
42:27metabolism increase, it's going to cause
42:29all the chemical reactions to occur
42:30faster and it's going to cause their
42:32body frame to look a bit thinner. But
42:34like I said, that's not always going to
42:36be the case. The reason why is because
42:38now with an increased metabolism, you're
42:40going to tend to eat more as well. So,
42:43now when you eat more, what's that going
42:44to do? It's going to indirectly increase
42:46that weight on the body.
42:48So, we can't say every single patient
42:51that has hyperthyroidism is going to be
42:54skinny. No, that's not the case always.
42:58So, body heat production. So, how are
43:00they going to feel? They will be feeling
43:03hot all the time. These are people who
43:06are sitting there turning the AC on in
43:07like the the winter.
43:12Maintains blood pressure.
43:14So, you should be able to go through and
43:16understand basically what is happening
43:18when you have too much
43:20and also if you don't have enough
43:22thyroid hormone. So, in hyper and hypo,
43:24you should be able to figure out there
43:25as well.
43:28Next then are the parafollicular cells.
43:30So, when we talk parafollicular cells,
43:33here you can appreciate those
43:34parafollicular cells. These
43:35parafollicular cells, they are also
43:37known as the C cells as we can see there
43:40of that thyroid gland. And their job is
43:43to produce calcitonin. Their job is to
43:46produce calcitonin.
43:48Calcitonin is a polypeptide
43:52hormone. It's a polypeptide hormone.
43:55Calcitonin is going to target
43:58the skeleton.
44:00Targets the skeleton and has a
44:02bone-sparing
44:04effect on the skeleton. It has a
44:06bone-sparing effect on the skeleton.
44:09When I say has a bone-sparing effect,
44:11because it's job is to lower your blood
44:13calcium levels.
44:15Lowers your blood calcium levels
44:17antagonizing the effect of parathyroid
44:19hormone.
44:21Antagonizing the effect of parathyroid
44:23hormone.
44:29Next then here we've got
44:31parathyroid glands. Now, we talk about
44:33our parathyroid glands, they are tiny,
44:36yellow to brown glands.
44:40So, here you can see all the when I was
44:42telling you target organs, target cells,
44:44you've got to be able to go through all
44:45of these different systems here and
44:47understand how this hormone is going to
44:49be affecting those systems. So, you can
44:51see thyroid hormone has got a very
44:53important job in our bodies.
44:57Before we jump on to those glands here,
44:59I want to mention to you guys a couple
45:00of conditions parathyroid glands here. I
45:02forgot to mention goiter.
45:04This young man here on the left-hand
45:06side has a goiter. Goiter can happen
45:07from hyper- or hypothyroidism.
45:12And then here we can see this young lady
45:14here has exophthalmos
45:17where you have the protruding of the
45:19eyes from basically their sockets. And
45:22this is usually due to too much protein
45:24deposition towards the the in the back
45:26of the eye and it causes the eyes to
45:28have that appearance there,
45:29exophthalmos. It's quite common in
45:31patients with Graves' disease as well.
45:36So, here are the parathyroid glands. You
45:38can appreciate uh
45:39those glands there and like we said,
45:42parathyroid glands usually four.
45:44However, the quantity can vary anywhere
45:46from two to four. We can have three to
45:48four.
45:49Uh but four is usually what we see
45:51average. The location of these basically
45:54glands, these glands are going to be
45:55found on the posterior aspect of the
45:57thyroid gland. Found on the posterior
45:59aspect of the thyroid gland.
46:02Yep, one time, you know, there was a
46:03time where we didn't even know that they
46:04existed there.
46:08So, here when we go through, we talk
46:09about the parathyroid glands. Here now
46:11is what they'll look like
46:13macroscopically, but then we throw them
46:15under the microscope, we've got a nice
46:16image here depicting both for you.
46:18So, here under the microscope, we can
46:20appreciate those glands. Now, when we
46:21throw them under the microscope, first
46:23cell here that we have is the chief
46:25cells. The chief cells are very numerous
46:28in quantity.
46:29They are numerous in quantity and they
46:31are small. They're small cells and they
46:35secrete PTH. They are very small cells
46:37and they secrete PTH. PTH or parathyroid
46:41hormone.
46:43It is also known as parathormone.
46:48Parathormone.
46:53Now, when we talk about
46:57thyroid parathyroid hormone, parathyroid
46:59hormone, its target organs are going to
47:01include number one,
47:03we can see here we've got the skeleton.
47:09Number two, kidneys and number three,
47:12the intestines. So, here at the level of
47:14the skeleton, what it's going to do is
47:16it's going to stimulate osteoclast.
47:19And what osteoclast are going to do is
47:21they're going to break down bone. So,
47:23when we break down bone, this increases
47:25the levels of calcium and phosphates
47:27into the blood.
47:28So, the function of parathyroid hormone
47:31is the opposite of what we saw with
47:33calcitonin.
47:37Calcitonin removed this excess calcium
47:40from the blood and deposited into the
47:42bone. Here we're low in calcium and
47:45we're going to remove it from the bone.
47:46So, once a bone gets broken down because
47:49of the osteoclast, this helps to release
47:51the calcium into the blood.
47:54Then we talk kidneys. Kidneys, PTH makes
47:57its way over to the kidneys as well. PTH
47:58is going to act on the kidneys by
47:59increasing calcium reabsorption.
48:03Right? From those kidneys' tubules.
48:06ADH, I think we have to go back and
48:09remember ADH, I told you guys to know
48:10where ADH works at as well. ADH is going
48:13to work, so we can't just say kidney,
48:15kidney, kidney, right? You're going to
48:17start knowing kidneys themselves are
48:18made up of certain part, the nephron
48:20that we talked about in the beginning,
48:22the first day of class.
48:24A lot of you guys weren't familiar with
48:25that.
48:27Even those of you coming from bio 107,
48:28so you got to make sure you're familiar
48:30with that nephron. It's a very important
48:32structure in relation to that kidney.
48:34So, when we talk ADH, ADH was going to
48:36work at the distal convoluted tubule
48:39and the collecting ducts.
48:41Now, here when we talk PTH, PTH you'll
48:43see now is going to be working on the
48:45loop of Henle. It works on the loop of
48:48Henle. And what does PTH do? PTH is
48:50going to increase calcium's reabsorption
48:53in by the kidneys' tubules or in those
48:56kidneys' tubules.
48:59So, PTH makes its way over to the
49:00kidneys. It makes its way over to the
49:01loop of Henle. Specifically speaking,
49:03even more specifically speaking, you're
49:04going to know there's a couple of
49:06different parts in the loop of Henle and
49:07where exactly it's at.
49:10And here again, it's going to increase
49:12calcium reabsorption.
49:14So, if PTH isn't in the picture, what
49:16kidney would do is it would remove any
49:17excess calcium that it doesn't need. But
49:20however, when PTH comes into the
49:21picture, that's going to be telling us,
49:23"Hey, we need to absorb more calcium."
49:26And so then that's what the kidneys will
49:27do instead of dumping it out in the
49:30urine.
49:31Third then here we can see the
49:32intestines. Now, how does this work?
49:34Here, PTH is going to promote the
49:37kidneys activation of vitamin D.
49:40Now, which then increases the calcium
49:43absorption from our food. So, here you
49:45have an indirect
49:47action taking place.
49:53So, the function of PTH is to increase
49:56calcium levels.
49:58Increase calcium levels in the blood. To
50:01increase calcium levels in the blood.
50:03Next in are the adrenal glands. The
50:05adrenal glands. Adrenal glands are found
50:07as a pair.
50:09They are pyramid-shaped
50:11glands.
50:13And they are enclosed in a fibrous
50:15capsule. And they are enclosed in a
50:18fibrous capsule.
50:21Along with that fibrous capsule, they're
50:23going to be protected or cushioned
50:27by fat. So, first you have a capsule
50:30surrounding them, and then surrounding
50:31that capsule is going to be fat. It's
50:33going to be adipose.
50:38Here you can appreciate that now very
50:39nicely. You've got the capsule.
50:42And then we've got the rest of that
50:43gland. We'll go through and we'll check
50:44out.
50:46So, when we talk about this adrenal
50:47gland, the adrenal glands found as a
50:49pair as we said. So, right and a left
50:51adrenal gland. They're pyramid-shaped.
50:53And they're going to be found located on
50:55top of each kidney.
50:57On top of each of the kidneys. So,
50:58suprarenal
51:00glands they are also known as.
51:07Now, the target organs. When we talk
51:08about the target organs. Now, here we're
51:10getting into the adrenal cortex. So, the
51:13cortex of the
51:15of the adrenal gland. Now,
51:17we're going to see the hormones that are
51:18going to be released from here. Where
51:19are they going to go and target? So,
51:21when we go we go through and we talk
51:23about the zona glomerulosa. The zona
51:25glomerulosa is one of the three
51:27divisions of that cortex. So, the cortex
51:29gets divided up into three parts. You
51:31can see that here very well.
51:32You've got the zona glomerulosa, zona
51:34fasciculata, and then here we've got the
51:35zona reticularis.
51:37So, all three of those divisions make up
51:39the cortex. And then internal to that
51:40cortex we've got the medulla.
51:43Then we have the medulla.
51:44Now, when we go through and we talk,
51:46let's talk first zona glomerulosa. When
51:49we talk zona glomerulosa, the zona
51:50glomerulosa is going to be the most
51:53superficial layer of all the layers. You
51:57can see it's right at the border with
51:59the capsule.
52:01So, when we talk zona glomerulosa, it's
52:04the most superficial layer. And this
52:06zona is important because it's going to
52:07be producing mineralocorticoids. It
52:10produces mineralocorticoids.
52:13Mineralocorticoids now, their function
52:15is to regulate electrolyte
52:17concentration.
52:19Their function is to regulate
52:21electrolyte concentration.
52:23And then the most important
52:24mineralocorticoid that you'll be
52:25responsible for knowing about is going
52:27to be good old aldosterone.
52:31Aldosterone.
52:33I like to call big Al. Aldosterone is
52:36very important.
52:39So, what does aldosterone do? It
52:41regulates electrolyte concentration.
52:45Aldosterone is going to target the
52:47kidneys. Again, we're saying kidneys.
52:48More specifically speaking, it will be
52:50you'll see the distal tubules.
52:53They will be the distal tubules.
52:56Now, when we go through and we talk
52:59aldosterone, its function is to increase
53:02blood levels of sodium.
53:05Its function is to increase blood levels
53:07of sodium.
53:14So, here when we talk
53:17aldosterone, it's important we mention
53:19and we talk about the RAAS system. When
53:21we talk about the RAAS system, the RAAS
53:22system is a system we have in the body.
53:24It's made up of various components that
53:27are going to help maintain blood
53:29pressure.
53:30So, now the RAAS system, here what
53:32happens is if you have low
53:36Let's see here.
53:38Okay. So, let me see. Can I go here?
53:42Maybe right here would be better.
53:44So, here we could see now we've got the
53:46kidneys and we have the adrenal glands.
53:48Now, if for some reason in our bodies
53:51our sodium level was to come down
54:02right? Or our water volume is low.
54:05Our water pressure is low inside the
54:07body.
54:13Here what's going to happen is
54:16we've got this one
54:19basically uh you'll see this one hormone
54:22making its way from
54:25the kidneys.
54:26Here we're going to see now we've got
54:29renin. We're going to go through and
54:30we're going to talk about. That's this
54:32whole name of this whole system. This is
54:33the RAAS system. R A A S. I wish this
54:38was a little bit better for the writing.
54:41So, renin
54:45renin
54:46angiotensin-aldosterone
54:48system is what we're looking at. So,
54:50here now if you have these two signals
54:52appear, what's going to happen is now
54:55this will basically activate renin.
55:00Renin, what it does it's going to
55:02convert angioten
55:05sinogen.
55:06It will convert angiotensinogen.
55:09We'll
55:10put AG there. Into
55:13angiotensin
55:15one.
55:24It will convert.
55:27So, if sodium levels fall, blood our
55:29water pressure goes down.
55:31Renin uh renin will come in and it will
55:34activate. It'll activate angiotensinogen
55:38into angiotensin one.
55:40Angiotensin one
55:42then gets converted to angiotensin
55:46two.
55:48Thanks to
55:50we'll see ACE.
55:52ACE stands for angiotensin
55:56converting
55:58enzyme. So, what's it going to do?
56:01Like the saying says, angiotensin
56:02converting enzyme, it's going to convert
56:03angiotensin one to angiotensin two.
56:06ACE converts angiotensin one to
56:08angiotensin two. ACE stands for
56:10angiotensin converting enzyme. ACE comes
56:13from
56:14the endothelium of your lungs.
56:16Comes from the endothelium of your
56:18lungs. You've got to know what
56:19endothelium is. We discussed that so
56:21about 2 months ago.
56:22So, ACE comes in and it converts
56:24angiotensin one to angiotensin two.
56:26Angiotensin two then is going to make
56:29its way over to
56:31the zona
56:32glomerulosa.
56:34Where it will then stimulate the release
56:37of
56:38aldosterone.
56:39Right? Big Al we said.
56:41And what does aldosterone do?
56:43Aldosterone then is going to make its
56:45way over to the kidneys we said.
56:47And exactly.
56:49Exactly.
56:50So, here aldosterone comes into the
56:52picture. And aldosterone we said is
56:55going to be responsible for increasing
56:57blood levels of sodium. So, here it
57:00makes its way over to
57:03the kidneys I told you.
57:05Makes its way over to the kidneys, it's
57:07going to help increase that reabsorption
57:10of sodium.
57:13So, when sodium comes in now, the
57:15kidneys pick up sodium. Guess what
57:17follows sodium?
57:18Water. Very good. Water.
57:22So, here now with aldosterone coming
57:24into the picture, what does aldosterone
57:26do? Increases
57:28our sodium.
57:33Look at the original signal.
57:37Okay? And it increases
57:40with sodium goes water.
57:42Then we increase that water intake.
57:45What's this doing to
57:47our blood pressure?
57:49All of this is going to increase
57:51your blood pressure.
57:54That's why you got to know this.
57:57For blood pressure.
58:04Your RAAS system.
58:06Next thing we have the zona fasciculata.
58:10The zona fasciculata.
58:13Now, when we go through and we talk zona
58:14fasciculata, that's going to be the
58:16layer right after them this zona
58:19we saw here now, the zona glomerulosa.
58:21Now, we talk zona fasciculata, zona
58:24fasciculata is found just deep to the
58:27zona glomerulosa.
58:29We talk zona fasciculata, the zona
58:31fasciculata is the second layer, so we
58:32can say there. The zona fasciculata now
58:35is going to be responsible for
58:37manufacturing and releasing an important
58:39glucocorticoid that you'll have to know
58:41about. The important glucocorticoid that
58:43you have to know about is going to be
58:46cortisol. Now, we talk about cortisol,
58:48cortisol's target organs are most body
58:51cells.
58:53Its function is to influence the energy
58:56metabolism. It's to influence our energy
58:59metabolism and also help us to resist
59:02stressors. And to help us resist
59:04stressors. And how will it do that? By
59:06increasing glucose levels. By increasing
59:09glucose levels.
59:12Right? You're stressed out. One thing we
59:14need glucose. Why? What is glucose going
59:16to do for us?
59:19Very good. You know my two favorite
59:20words.
59:22Cellular respiration.
59:26So, here when we go through and we talk
59:28adrenal glands and after the zona
59:30fasciculata, right? So, you have to be
59:32able to talk about that during stress
59:33and get that zona fasciculata taken care
59:35of there.
59:36So next then after the zona fasciculata
59:38then we've got zona reticularis, this
59:39third layer. And then we talk zona
59:41reticularis, the zona reticularis is
59:43going to be important because it's
59:46going to release hormones here as well.
59:48It's a deepest layer of the three.
59:52And then when we talk zona reticularis,
59:53the zona reticularis produces a small
59:55amount of adreno sex hormones. It
59:59produces a small amount of adreno sex
1:00:02hormones. So one way to remember this
1:00:04gland is the deeper it gets the sweeter
1:00:07it gets. I usually joke with my students
1:00:08and I tell them that. The deeper it gets
1:00:10the sweeter it gets, right? You start
1:00:13off with salt,
1:00:14glucose, and then sex hormones. Yeah, I
1:00:18don't know. It's something nobody ever
1:00:21forgets. I was taught that in school and
1:00:24uh it's in most of our books as
1:00:26mnemonics and you'll be able to see that
1:00:27there as well.
1:00:29So that takes care of then our zona
1:00:32reticularis. Next then let's move into
1:00:35the medulla from the cortex then. So
1:00:37let's move into the medulla from the
1:00:38cortex. Now when we talk medulla,
1:00:40medulla is the most deepest part. The
1:00:42medulla is more like a knot of the
1:00:45nervous system than a gland. It's a also
1:00:48a part of you'll see the sympathetic
1:00:50system.
1:00:51And the reason why is because we're
1:00:53going to see produced and released here
1:00:55are catecholamines,
1:00:57catecholamines. And catecholamines
1:01:01you'll have to know about are going to
1:01:02include epinephrine and norepinephrine.
1:01:05And catecholamines,
1:01:08their function
1:01:09or their target organs is going to be
1:01:12the same target organs
1:01:15as
1:01:16the sympathetic nervous system. The same
1:01:19target organs as the sympathetic nervous
1:01:21system because it's going to have the
1:01:22same effects.
1:01:23So if you understood sympathetic nervous
1:01:25system, we went through all the
1:01:26different functions, we talked about
1:01:28that, that's exactly what you're
1:01:29relating this to
1:01:31bronchodilation,
1:01:33right? Pupillary dilation.
1:01:35Okay, we went through and we talked
1:01:37about all of that there as well.
1:01:40So adrenal medulla. That
1:01:43then
1:01:45So when we talk functions again,
1:01:47functions of catecholamines it's going
1:01:48to mimic your sympathetic activation.
1:01:50It's important you understand that.
1:01:51Increasing heart rate there as well, so
1:01:53we can keep going on and on.
1:01:55Next then let's move to the pancreas.
1:01:58Let's discuss the pancreas. Now when we
1:02:00talk pancreas,
1:02:03here before we jump off to pancreas,
1:02:04here we could see some of these uh
1:02:07cortical hormones. You've got these
1:02:09tables here giving you basically the
1:02:10idea of what's happening there.
1:02:12And same thing happening you can see
1:02:14here.
1:02:17And then here we have some uh other
1:02:19organs that are going to be responsible
1:02:20for producing some hormones. You have to
1:02:21know those and we'll go through those.
1:02:23We'll check uh basically you go you'll
1:02:25be able to go through and check those
1:02:25out there
1:02:27uh on your own as well. But I have a
1:02:28list for you. I'll go through those and
1:02:29I'll mention those for you guys at the
1:02:30end.
1:02:32Next then we have the pancreas. So when
1:02:33we talk pancreas, pancreas is going to
1:02:38All right, so let's continue with
1:02:40our pancreas.
1:02:44Excuse the hat. I went to the gym, took
1:02:46a shower, didn't feel like uh
1:02:48uh
1:02:50you know.
1:02:55All right, so like I was saying, sorry,
1:02:57I went to the gym.
1:02:58Didn't feel like doing my hair and
1:02:59stuff, so bear with the hat. All right,
1:03:01so let's talk pancreas then. Now when we
1:03:03talk pancreas, here we're talking about
1:03:05a very soft, triangular,
1:03:08mixed gland. Triangular shaped mixed
1:03:12gland when we talk pancreas. Now what
1:03:14we'll do is we'll move over to
1:03:17this image here where you can actually
1:03:18see the pancreas in its entirety. But
1:03:20let's actually move back to the original
1:03:22picture of all the endocrine glands and
1:03:24let's look at the pancreas here in
1:03:27relation to then all the other organs.
1:03:30So here you can see it better.
1:03:32Uh the reason why I say better because
1:03:33here you can see you've got the small
1:03:34intestine there as well.
1:03:36And you're able to appreciate the small
1:03:37intestine, so the digestive structures
1:03:39are in there as well.
1:03:40And um here the stomach would basically
1:03:42be found right in here. If I was to
1:03:44actually let's continue that. Let's draw
1:03:45it in. So if I was to draw it in, you
1:03:47would have something kind of like this
1:03:48coming up into here
1:03:51and then making its way around like
1:03:53this. Uh
1:03:54Kind of something like that coming
1:03:56around like this.
1:04:00And then making its way up.
1:04:02You've got like not exactly, but uh
1:04:05so what we could do best with here. So
1:04:07you would have the stomach there. Now
1:04:08you can appreciate that uh
1:04:10the small intestine and then the
1:04:11pancreas. So moving back, it's a small,
1:04:14soft,
1:04:16triangular
1:04:18shaped mixed gland.
1:04:20Now when we talk uh
1:04:22pancreas, pancreas is going to be a
1:04:23special gland. The reason why the
1:04:25pancreas is a special gland because the
1:04:26pancreas is considered to be a mixed
1:04:27gland. Now when we say that the pancreas
1:04:29is considered to be a mixed gland, here
1:04:31now we're going back to the point we
1:04:33were making in the beginning when we
1:04:34were talking about endocrine and
1:04:35exocrine glands. So this is where you'll
1:04:37see that's going to come into play.
1:04:39Next then here when we move through,
1:04:41here we're going to be able to see
1:04:43uh the the location. So when we talk
1:04:44location now you can see it's found in
1:04:46the abdomen, partly behind the stomach.
1:04:50So in the abdomen, partly behind the
1:04:52stomach.
1:04:53And you can see that here it's found
1:04:56right next to that small intestine. And
1:04:59more specifically speaking, we can say
1:05:01it's found right next to the duodenum.
1:05:04This is the duodenum of that small
1:05:07intestine. So getting more specific, you
1:05:09can see this is the duodenum it's going
1:05:10to be found in relation to that
1:05:12duodenum. Close proximity to the
1:05:13duodenum. Sometimes what happens is this
1:05:16pancreas
1:05:17grows extra tissue right here on the
1:05:19outside as well.
1:05:21And the tissue basically you can think
1:05:22of in circles.
1:05:24So with that extra tissue being grown
1:05:25there, it encircles that duodenum and it
1:05:27can cause it to be blocked as well and
1:05:29they refer to that as annular pancreas,
1:05:32annular pancreas.
1:05:34So here then moving
1:05:36down then here we're going to be able to
1:05:39go back and see. Now when we talk
1:05:40pancreas, so that's the pancreas
1:05:42macroscopically. Microscopically is what
1:05:44you're seeing right on the right. But in
1:05:46order to appreciate that, what we'll do
1:05:47is we'll move over to this image here
1:05:48where you can see it microscopically
1:05:50much better. So now microscopically
1:05:52speaking is what we want to talk about.
1:05:54Here what we see again we're going to be
1:05:56talking endocrine because that's all
1:05:57we're talking about right now. And we'll
1:05:58talk digestive we'll go through the
1:06:01exocrine component. Okay? So here when
1:06:04we go through we talk pancreas uh
1:06:06it's got these pancreatic islets you see
1:06:08there. A whole bunch of pancreatic
1:06:09islets. And these pancreatic islets,
1:06:11they're tiny cell clusters. They are
1:06:14tiny cell clusters and you say um what
1:06:18type of cells? We're going to go through
1:06:19those types of cells there as well.
1:06:22So they're they're tiny cell clusters
1:06:24that are going to produce pancreatic
1:06:26hormone.
1:06:27That will be responsible for producing
1:06:28pancreatic hormones.
1:06:30Now let's go through the different cell
1:06:32types. You have two main cell
1:06:33populations here. You have alpha cells
1:06:35and you have beta cells. Alpha cells and
1:06:39beta cells. First we talk alpha cells,
1:06:41our alpha cells are going to be
1:06:43responsible for producing glucagon as we
1:06:46can see here. They are they are our
1:06:49glucagon producing cells. Now the target
1:06:52organ for glucagon is going to be we'll
1:06:55see the liver.
1:06:56The reason why is because it's going to
1:06:58promote
1:07:00at the level of the liver it's going to
1:07:01promote
1:07:03glycogenolysis.
1:07:08Glycogenolysis.
1:07:15Where we're going to break down
1:07:17glycogen.
1:07:19So glycogenolysis.
1:07:21And when we break down glycogen this
1:07:23forms for us new glucose. So that
1:07:26process is called gluconeogenesis.
1:07:30All right, just break down each of those
1:07:31words and you've got everything figured
1:07:33out there.
1:07:34So
1:07:35it'll target the liver where it's going
1:07:36to promote glycogenolysis where you
1:07:39break down glycogen. Glycogen we all
1:07:41learned in bio,
1:07:42right? Is the storage form of glucose.
1:07:45And where do we find it stored?
1:07:48You see how it all makes sense now?
1:07:51Now when we go through and we talk
1:07:53functions, so the function of glucagon
1:07:55is to release glucose
1:07:57into the blood.
1:07:59So glucagon is going to release
1:08:01glucose into the blood by breaking down
1:08:04that glycogen.
1:08:07Next then are the beta cells. Beta
1:08:09cells.
1:08:10Beta cells are going to be responsible
1:08:13for producing insulin. Insulin.
1:08:19Now the beta cells produce insulin.
1:08:20Insulin is going to target most body
1:08:23organs. It will target most body organs.
1:08:26And the main function here that I'd like
1:08:28you to know about is going to be that
1:08:30it's going to lower blood glucose
1:08:32levels. It will lower blood glucose
1:08:34levels.
1:08:38It's also going to influence
1:08:41protein and fat metabolism. It will also
1:08:44influence protein and fat metabolism.
1:08:48Insulin is very important in neuronal
1:08:50development.
1:08:55It's also involved in our feeding
1:08:57behaviors.
1:09:00Also in learning and memory.
1:09:04So very very important. Main function
1:09:06you're going to be seeing it for and
1:09:06you're going to be using is going to be
1:09:08lowering blood glucose levels.
1:09:12Right, patients' glucose levels are too
1:09:13elevated, uh their body doesn't do what
1:09:15it needs to do, we call in then the big
1:09:16guns.
1:09:20Next let's move to the gonads. Let's
1:09:22talk gonads.
1:09:24Now when we talk gonads, we're talking
1:09:25testes or ovaries depending on which sex
1:09:27we're talking about. So, here first
1:09:30let's talk gonads. Gonads are Let's talk
1:09:32ovaries first. I'm sorry, the female
1:09:33gonads. When we talk female gonads, the
1:09:35ovaries, they're found as a pair.
1:09:37They're going to be found as a pair.
1:09:39There are two of them.
1:09:42They're found as a pair. They're going
1:09:44to be found located
1:09:46in the females abdominal pelvic cavity.
1:09:49So, the ovaries are found as a pair.
1:09:51They're small oval organs.
1:09:54Small oval organs found in the females
1:09:57abdominal pelvic cavity.
1:10:01Now, they're going to be responsible for
1:10:03basically you'll see producing and
1:10:05releasing estrogen. They'll be
1:10:06responsible for producing and releasing
1:10:09estrogen.
1:10:17So, here when we go through and we talk
1:10:19estrogen in relation to the female
1:10:21gonads, I want you guys to know the
1:10:24target organ
1:10:25that estrogen is going to target now
1:10:28when it gets released from basically the
1:10:30ovaries, it will target the female
1:10:32reproductive organs. And its function
1:10:35Its function is that it's responsible
1:10:38for the maturation of the reproductive
1:10:41organs.
1:10:42It's responsible for the maturation of
1:10:44the reproductive organs and also for the
1:10:47appearance of secondary sex
1:10:50characteristics of females at puberty.
1:10:53So, it's responsible for the maturation
1:10:54of the female
1:10:56reproductive organs
1:10:58and the appearance of the secondary sex
1:11:00characteristics
1:11:02in females at puberty. So, we talk
1:11:04secondary sex characteristics, we're
1:11:06talking
1:11:07enlargement of the genitalia, the
1:11:09appearance of pubic hair, basically
1:11:12that's what we talk when we get into
1:11:13appearance of secondary sex
1:11:14characteristics.
1:11:17Next then we've got progesterone. Next
1:11:19hormone here with relation to the
1:11:20ovaries, we've got progesterone. When we
1:11:21talk progesterone, progesterone, you'll
1:11:23see it's going to target also the
1:11:24females reproductive organs. And its
1:11:26function is that it promotes breast
1:11:28development. It will promote breast
1:11:31development.
1:11:32And also it's involved in the cyclic
1:11:34changes in the menstrual cycle. It's
1:11:36also involved in the cyclic changes in
1:11:38the menstrual cycle.
1:11:43Progesterone's involved in pregnancy. It
1:11:46supports gestation. It's involved with
1:11:49pregnancy and it supports gestation.
1:11:53And it's involved in embryogenesis.
1:11:55And it's important in embryogenesis.
1:12:00Next then we've got our testes. When we
1:12:03talk testes, here we can appreciate the
1:12:04testes in the bottom picture. We'll look
1:12:06at them in greater detail when we get to
1:12:08each of the when we get to the
1:12:09reproductive system, we talk each
1:12:11respective reproductive system there as
1:12:12well.
1:12:13Now, when we talk testes, testes
1:12:16they're going to be found located in the
1:12:18anterior side. They are in
1:12:21the anterior side
1:12:26of the male body in an extra-abdominal
1:12:30skin pouch. They are found on the
1:12:32anterior aspect in an extra-abdominal
1:12:36skin pouch that we refer to as the
1:12:38scrotum.
1:12:40So, they're found in an extra-abdominal
1:12:43skin pouch called the scrotum.
1:12:45And again, we'll talk about that in
1:12:46greater detail when we get to male
1:12:48reproductive. So, let's talk then
1:12:50testosterone here. Testosterone
1:12:51Testosterone is going to target male
1:12:54reproductive organs. When we talk
1:12:56testosterone, testosterone I want you to
1:12:58know during puberty.
1:12:59During puberty here now it's going to
1:13:01initiate maturation of the male
1:13:03reproductive organs.
1:13:05Here it's going to be involved
1:13:08in the appearance of
1:13:10the males secondary sex characteristics.
1:13:14So, testosterone during puberty
1:13:16initiates maturation of the male
1:13:18reproductive organs and the appearance
1:13:21of secondary sex characteristics
1:13:24in the male as well.
1:13:28And the appearance of
1:13:33So, involved in the appearance of
1:13:35secondary sex characteristics
1:13:37during puberty it initiates
1:13:39the maturation of the male reproductive
1:13:41organs
1:13:42and it's involved with we spoke about
1:13:44earlier
1:13:45normal sperm production as well.
1:13:49Next then let's talk pineal gland. Let's
1:13:51talk pineal gland. Now, when we talk
1:13:53pineal gland
1:13:55this pineal gland
1:13:58is going to be found as a part of the
1:14:01epiphysis.
1:14:03I'm sorry,
1:14:04we went through we talked thalamus,
1:14:06hypothalamus and epithalamus. It's going
1:14:08to be a part of the epithalamus. Pineal
1:14:11gland is also known as the epiphysis
1:14:12cerebri.
1:14:14Also known as the epiphysis cerebri. So,
1:14:16at the roof
1:14:17you can see of the third ventricle where
1:14:19we saw the epithalamus.
1:14:21Even the posterior end of the corpus
1:14:22callosum, if you recall.
1:14:24Now, secretion peaks from age basically
1:14:281 to 5 years of age. And this gland then
1:14:31shrinks by about 75% at puberty.
1:14:34So, when we go through and we talk about
1:14:35this gland, this gland is a tiny pine
1:14:38cone-shaped gland.
1:14:41So, location we've gone through we've
1:14:42just mentioned.
1:14:43And it secretes melatonin.
1:14:46And the target organs for melatonin,
1:14:48you'll see is going to be basically
1:14:50different parts of the body.
1:14:52Let's talk function. Now, when we talk
1:14:54function the function is not fully
1:14:56clear.
1:14:58However, we believe that melatonin is
1:15:00going to function as a very powerful
1:15:03antioxidant.
1:15:05It functions as a very powerful
1:15:07antioxidant.
1:15:10And
1:15:13that melanin
1:15:15melatonin is going to be involved
1:15:19in our circadian rhythms. It's involved
1:15:21in our circadian rhythms.
1:15:25So, basically what happens is it
1:15:26receives signals from our visual pathway
1:15:30about dark and light cues.
1:15:35So, then it's involved in basically
1:15:36sleep. We could say that we could say
1:15:38there. And it's also involved in our
1:15:41mood
1:15:42as well.
1:15:44So, plays a role in
1:15:47our moods.
1:15:49Next then here we have the thymus.
1:15:52When we talk thymus, thymus is large and
1:15:55conspicuous.
1:15:57And then it diminishes
1:15:59in adulthood.
1:16:01So, it's large and conspicuous
1:16:05and then it diminishes in adulthood.
1:16:09And it gets replaced by fat and
1:16:10basically fibrous connective tissue. It
1:16:13gets replaced by fat and fibrous
1:16:15connective tissue.
1:16:18Now, when we go through and we talk
1:16:19about
1:16:20the thymus, the thymus is going to be
1:16:23found located deep to the sternum. So,
1:16:26it's found located deep to the sternum
1:16:28in the thorax
1:16:31on top of the heart and in between the
1:16:34lungs.
1:16:38Now, when we talk about the thymus, I'd
1:16:40like you to know about thymosins
1:16:44thymopoietin and thymulin.
1:16:48Now, these hormones
1:16:49they're going to be involved in the
1:16:51normal development. They're involved in
1:16:54the normal development of lymphatic
1:16:56organs
1:16:58and T cells.
1:17:01Our T lymphocytes.
1:17:04Our T lymphocytes actually come to the
1:17:06thymus to mature we say. That's kind of
1:17:09like
1:17:10the thymus is high school for
1:17:13our T lymphocytes.
1:17:18High school for our T lymphocytes.
1:17:25Next then here I've got a list at the
1:17:27end of your note taker of other hormone
1:17:31producing organs. So, I'd like you to go
1:17:33through each of those from your note
1:17:36taker and make sure you've got the
1:17:37hormones found in relation to them
1:17:40understood as well. So, you got the
1:17:42hypothalamus, you got the heart, the GI
1:17:44tract, placenta, kidneys, skin, adipose
1:17:47and skeleton.
1:17:52So, go through them
1:17:55as well
1:17:56and get those checked off.

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