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Endocrine gland hormone review | Endocrine system physiology | NCLEX-RN | Khan Academy

October 15, 2019

Have you ever
thought about the way the different parts of
our body communicate? I think we often
consider the body to be this one complete
thing, this self. But really our body is
composed of lots of parts. There are lots of organ systems. And each of those has organs. And all of those organs
are made of tissues. And all of those tissues
are made of cells. And it’s crazy, but
there are 100 trillion– or at least roughly 100
trillion cells in our body. So it’s curious then how
do those 100 trillion different parts communicate? Well, one way is through
the nervous system and through the pre-laid
tracks of nerves. But not every part of the
body is connected by nerves. I mean how, for example,
would part of the brain go about communicating
with part of the kidney? Well, to talk about
that we’re going to have to talk about
the endocrine system. And the endocrine
system is a system of organs that
are called glands. And these glands secrete
little chemical messages that are called hormones. And they release those
little chemical messages called hormones
into the bloodstream so that they can circulate
from one part of the body to another part of the body in
order to initiate an effect. And there are many
parts of the body that use these hormones
to communicate. But certain organs
are really defined by this method of
communication and we call them endocrine glands. And so one of the
major endocrine glands is the hypothalamus. And the hypothalamus
is located right here. It’s a member of the forebrain. And as a member of the brain, it
receives a lot of those signals that we talked about
from the nervous system. So those nerve signals are
funnelling into the brain. And the hypothalamus
then, as a kind of dual member of
the endocrine system, funnels those signals
into the pituitary gland. And so because it
plays that dual role between the endocrine system
and the nervous system, it often gets taglined
as the control center of the endocrine system. In addition to stimulating
the pituitary gland, the hypothalamus actually make
some hormones itself also. And so it makes
ADH and oxytocin. And ADH is antidiuretic hormone. And it’s a main regulator of
our fluid volume in our body. And then oxytocin is a hormone
that stimulates the uterus to contract for females
during pregnancy. And so that’s the
hypothalamus, member of the brain and member
of the endocrine system where it all begins,
the control center. And then right below
the hypothalamus is the pituitary gland. And the pituitary gland
is located right here, dangling right below. And so the hypothalamus is
about the size of a grape. And the pituitary
gland is actually about the size of a green pea. But this little green
pea is so important that it’s called
the master gland. And it’s called the master gland
because the pituitary gland takes that stimulation
from the hypothalamus and it directs it to all of
the other endocrine glands, or at least almost all of
the other endocrine glands, such that their
function is ultimately dependent on the pituitary
gland to work well. And so that little green pea
is a really important part of the endocrine system. And so one of the
endocrine glands that the pituitary directs
is the thyroid gland. And the thyroid gland is
located right here in your neck. It wraps around your trachea. And your trachea
is your windpipe. And so you can feel this
thyroid gland on your neck as you swallow. If you hold your hands right
around your Adam’s apple and swallow, that meaty
thing moving up and down, that’s your thyroid gland. And one of its main
jobs is regulating your body’s metabolism. And it does that through the
thyroid hormones T3 and T4. And another name for
T3 is triiodothyronine. And another name
for T4 is thyroxine. But the thyroid uses these
hormones, the thyroid hormones, to stimulate the body’s
metabolism, which is crucial because that’s how
our body gets energy. And then right behind
that thyroid gland are four spots
known collectively as the parathyroid. And the main role
of the parathyroid is regulating our body’s
blood calcium level. And the level of
calcium in our blood is hugely important
because calcium does a lot of stuff
in our bodies. It’s involved in
muscle contraction. It’s involved in bone growth. And all of those functions are
really sensitive to the level of calcium that’s floating
around in our blood. And so the parathyroid
glands, those four spots on the back side of our
thyroid, regulate calcium through the parathyroid
hormone, or PTH. And then moving down the torso,
we have the adrenal glands. And the adrenal
glands are located right on top of
the kidneys here. And they’re called
the adrenal glands because they’re adjacent to
or right next to the kidney system, which is called the
renal system in medical speak. But we really need to further
divide the adrenal glands into two parts, the outer
part and the inner part. So the outer part is the
cortex and the inner part is the medulla. And the reason for
the distinction is that the inside and the
outside of the adrenal glands have two different functions. And so we’ll start with
the outside or the cortex. And that’s where the steroids,
the adrenal corticosteroids, are made. And two major
examples of steroids made in the adrenal cortex
are cortisol and aldosterone. And cortisol is one of the
body’s stress hormones. So it functions to increase
blood sugar in times of stress so we have energy. And it also has some
anti-inflammatory functioning. And then aldosterone is
one of the major regulating hormones of our
body’s blood volume and how much fluid is in
our veins and arteries. And so that’s the cortex. And then the medulla
makes a class of hormones called
catecholamines. And two major examples
of catecholamines are epinephrine
and norepinephrine. And I’m going to shorten
those as epi and norepi. And sometimes epinephrine
is called adrenaline. And that might be a little
bit more familiar to you. But these catecholamines
are really involved in our body’s fight
or flight response, that adrenaline response that we
have to a stressful or scary situation. And so the medulla
and the cortex make up the adrenal glands. But moving down the
list and down the body, we have the gonads. And in females, those
are the ovaries, and in males, the testes. And the gonads release
the sex hormones. And so in males, the testes
produce testosterone. And in females,
the ovaries produce estrogen and progesterone. But these sex
hormones are mainly involved in the development
of our secondary sex characteristics like pubic hair,
and larger frames in males, and breasts in women. But they’re also involved
in progressing us through those life stages
that accompany those sex characteristics, like
puberty and menopause. And then last, but not
least, we have the pancreas. And it’s located right here in
the upper part of the abdomen. And I saved the
pancreas for last because it isn’t
involved as directly with the pituitary glands as the
other endocrine hormones were. But it still uses those
hormones to stimulate an effect in a different part of the body. And the effect that
the pancreas stimulates is control over the blood sugar. And it does that through the
hormones insulin and glucagon. And the pancreas is
vitally important because without its hormones
insulin and glucagon, we can’t regulate
how much sugar is in the body’s blood
versus the cells. And that can lead to major
diseases like diabetes. And so with the
pancreas, we can conclude our list of major
endocrine glands. And so as we look at these
glands and at these hormones and we think about all of
the different effects that are being stimulated
in our body by them, it becomes pretty clear
that there aren’t just a few of these circulating
in our bloodstream. There are literally loads
of hormones circulating through our vasculature
at any given moment. And so that poses a
potential problem. If, say, that
you’re in the brain and you’re trying to tell
something to the kidney, you’re trying to
send him a message, and you put that
in the bloodstream and you just float
it down to him, how do you know that
it’s going to get there? I mean, isn’t that what
every other endocrine gland is trying to do? Well, it turns out that hormones
are a lot like radio waves. In your city or in your town,
there are many different radio stations and there are
many different songs being played at any given
time by those radio stations. And even maybe
from the next town over, there are radio waves
filling the air of your town. But unless you’re tuned in
specifically to that station, you’re not going to pick
up on the song that’s being transmitted. And in a very similar
way, a hormone is not going to be
received unless there’s a very specific receptor
on the target cell. And so the receptor
and its location are very important in
determining the hormone function. And we have classes that we
use to help us identify which hormones fall into
which function. And so the first class
are autocrine hormones. And the autocrine
hormones function at the cell that makes them. An example of this is the
T-cell in the immune system. It actually secretes
a hormone that it makes called an
interleukin, that signals the cell itself to
increase its effectiveness and its immune function. And then another
class of hormones are paracrine hormones. And paracrine hormones
function regionally. And an example of that might
be the hormones released by the hypothalamus that
direct the pituitary gland. And then last, but
not least, kind of the classic class of hormones
are the endocrine hormones. And these are the hormones
that function at a distance. And an example of this might be
the pituitary gland stimulating the gonads, way far away. And so we have
autocrine, paracrine, and endocrine
classes that help us determine how a
hormone functions. And so I know I just told you
a whole lot about hormones. But this is your introduction
into one of the most important ways that the 100 trillion
little tiny individual parts of your body communicate.

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  • Reply Sorin September 19, 2013 at 10:36 am


  • Reply jgmenator September 26, 2013 at 11:17 pm

    Yes, because obviously I'm watching this video to be entertained.
    Stop hating. Dude did a great job.
    Also: "boring" not "booring."

  • Reply jgmenator September 27, 2013 at 3:05 pm

    I see what you're saying, but realize: being able to even watch "many videos in a row" isn't a right. It's a privilege. You clicked on this specific video for a reason (to learn) and you're able to do so for free. Have some humility. Be humble. Say thank you to content creators for even MAKING the videos. If you don't like something, just close it.

    To wit: Ryan, thanks for the video! Helped me out a lot, and its clarity and conciseness allowed for easy note-taking. Appreciate it!

  • Reply Ryan Patton September 27, 2013 at 9:35 pm

    thank you all for the feedback!

  • Reply Ryan Patton September 27, 2013 at 9:35 pm

    thanks for the constructive criticism! keep it coming 🙂

  • Reply Matthew October 7, 2013 at 1:52 pm

    Are you Kenneth from 30 Rock?

  • Reply Rose LeAnn October 18, 2013 at 7:49 pm

    You have literally helped me Pass my last two Anatomy and Physiology exams through your videos. Please dont stop because I begin Nursing school in the fall and I will be Watching your videos!!!!!!!

  • Reply Edumus Cationes November 6, 2013 at 8:43 pm

    Great Job Rose Moore! Hope you fly through Nursing School. I am hopefully going to take my last pre-req in Physio next semester to apply to a Nursing program. Thank goodness for visual learning. Textbooks just puts me to sleep. This stuff is amazing!

  • Reply Edumus Cationes November 6, 2013 at 8:49 pm

    Khan Academy Medicine is AWESOME!! What takes me hours to learn either through dry textbook and dreadful power point lectures in school = only a few minutes in Khan Academy! And I actually understand it! You guys are AWESOME!! NEVER STOP!

  • Reply Taras Hrynchuk November 7, 2013 at 1:36 pm

    Another great great video! Thank you! Keep doing it!!!

  • Reply lalaa babhh November 23, 2013 at 3:14 pm

    great video, but why wasn't the thymus talked about? its still a part in the endocrine system.

  • Reply lalaa babhh November 23, 2013 at 3:25 pm

    what about the pineal gland?

  • Reply saryma hogan December 16, 2013 at 6:37 am

    Good job Rya

  • Reply Yashasvi Agarwal December 26, 2013 at 4:42 am

    How do you classify hormones from the heart such as atrial natriuretic factor (ANF) and from the kidney such as erythropoietin?

  • Reply Greg Balteff January 8, 2014 at 6:26 pm

    I love your little writing

  • Reply Guli Rozikova January 12, 2014 at 3:14 am


  • Reply vcc g February 19, 2014 at 2:24 am

    Very helpful, thank you very much.

  • Reply Emily Hughes March 3, 2014 at 1:30 am

    Not that it's a big deal, but just wanted to let you know that "Glucagon" is spelled with an "o" and not an "a" (glucagan is how you spelled it in the video) Thanks for all the awesome videos! I love Khan Academy 🙂

  • Reply Chris P. Bacon March 23, 2014 at 9:30 pm

    your writing is so cool wow i love it

  • Reply Nothing March 28, 2014 at 5:45 am

    I was under the impression that we only have 10 trillion human cells in our body, but 100 trillion bacterial cells.

  • Reply Katrina Williams May 3, 2014 at 5:58 am

    Thank you! for the easy break down.

  • Reply Zena Sklir July 2, 2014 at 11:33 pm

    Good ! Thank you .

  • Reply Jordan Sequeira July 13, 2014 at 11:55 am

    helpful… thnk you..

  • Reply cc021268 July 19, 2014 at 1:38 pm

    Very well explained. Thanks

  • Reply DALE thebelldiver July 28, 2014 at 5:12 pm

    All this is very well constructed but; I want to know what is the optimal medium which will promote best case for organ and glandular communication.  The conductivity must be as important at the actual ability to react to stimulus and respond with it's chemical or electrical stimulus to the proper degree.

  • Reply Carey Watkins September 10, 2014 at 1:21 am

    Very well explained!! Thanks

  • Reply Lula Zeta September 21, 2014 at 12:31 pm

    Bill Gates and his wife provided the funding for the creation of Khan Academy.  What a contribution!! and it is such perfect modality to educate anyone…for free.  God loves America and America (through its people) helps the world be a better place.  YouTube, is such a good channel.  Of course…the unscrupulous will use it to do harm.  The "good doers" must always outperform the bad ones.

  • Reply musiclife October 2, 2014 at 1:33 am

    The most helpful and great explaning video i have ever seen, thank You soooo much Mr. Awesomeee

  • Reply Barco E Kaitama October 31, 2014 at 3:42 pm

    well and easy to follow….great video

  • Reply Costa Gakidis November 7, 2014 at 2:15 pm

    Good video, however, I'd like if the video included the hormones released by the anterior and posterior pituitary glands. 

  • Reply Parinitha Maben December 6, 2014 at 1:56 pm

    That was so helpful! Thank you!

  • Reply Georgijana Balugo-Gilmore December 20, 2014 at 12:41 pm

    Whst happened to the Pineal Gland

  • Reply Rudrik Thakkar January 21, 2015 at 3:46 pm

    Great help! Thank you!

  • Reply Miranda Arms January 26, 2015 at 12:17 am


  • Reply Naleen del rosario February 15, 2015 at 7:36 am

    You forgot pineal gland.

  • Reply Nishat Karim February 25, 2015 at 1:27 pm

    Thankyou so much! makes learning so simple.

  • Reply Andrea Chavez April 1, 2015 at 5:52 am

    I thought ADH and oxytocin came from the anterior pituitary gland??

  • Reply Prashanth Raju May 2, 2015 at 7:42 am

    i think hypthalamus secretes only two hormones which controlle the function of pituitary gland. i.e, GHRH(growth hormone releasing hormone) and GHIH(growth hormone inhibiting hormone).

  • Reply Nate Manning May 12, 2015 at 12:39 am

    so.. what would happen if a guy had adrenal glands that were.. lets say.. mutated or evolved.. and were maybe 4x larger i guess.. .. would your kidneys or other body parts go out faster shortening their life span.. ?

  • Reply Ray Thandi June 9, 2015 at 6:28 am

    Thank you!!!

  • Reply shlomo goldbergstein June 13, 2015 at 4:58 pm

    How do you make a hormone? Don't pay her.

  • Reply femqu June 15, 2015 at 4:08 pm

    so much can be explained about the endocrine system that you can talk for dayssssss. I think this was a very good over view for some who is interested, non-medical student and has completely forgotten about high school biology or physiology. Thanks for your simply explanation on the endocrine system

  • Reply Simon Barton August 12, 2015 at 6:41 pm

    The captions are funny if you turn on the "auto-generated" version.

  • Reply White Dove September 16, 2015 at 8:34 pm

    Pineal and thymus?

  • Reply Oxxioney October 3, 2015 at 3:05 pm

    I came here to learn this for my big test at school…

  • Reply Danny Taylor October 19, 2015 at 9:26 am

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    ….Growth Sinerama Wmx Excellent product. Would recommend this to everyone… Search on Google ….

  • Reply иоѕиф Сталин November 6, 2015 at 3:11 am

    Thankssss my mom assigned me homework and I was like omg I'm screwed but it was fun and simple thanks man 🙂

  • Reply иоѕиф Сталин November 6, 2015 at 3:12 am

    Lol I'm 10 I didn't get like half of this

  • Reply Viktoria Mergler February 2, 2016 at 9:32 pm

    Awesome overview to help see how the endocrine system is set up and what hormones are produced where and how they work. Helped me. Thanks !

  • Reply pk dhaliwal February 5, 2016 at 6:14 am

    Helpful for everyone

  • Reply anthony bolson February 23, 2016 at 7:24 am

    Doesn't the oxytocin and ADH actually secrete from the posterior pituitary and not the hypothalamus?

  • Reply Ck Williams April 15, 2016 at 8:37 pm

    This guys voice is not as easy to listen to as others

  • Reply rakesh ranjan July 13, 2016 at 2:58 pm

    it helped me a lot in preparing

  • Reply rakesh ranjan July 13, 2016 at 2:59 pm

    for my exams ……….oh!!!!no but the video is incomplete OMG

  • Reply Angelica Rosa September 1, 2016 at 6:01 pm

    Hello, Thanks for you're research. I have Hypopituitarism and the Endocrinologist think it's Polyglandular Addisons. I've been on a high dose of Cortef for 17 years. Do you have any medical advice?

  • Reply Violet October 9, 2016 at 10:56 pm

    Great video thanks

  • Reply tenzin choekyi October 21, 2016 at 7:29 pm

    Isn't hypothalamus is the master gland? I read it in the Lewis med surg textbook…

  • Reply Habib Alrabaa December 2, 2016 at 3:32 am

    What about the thymus

  • Reply Brett Carter December 10, 2016 at 1:36 am

    ewww I'd like to hear a shrink's opinion on these people

  • Reply Stone Gyrl January 19, 2017 at 5:59 am

    I thought the master gland is the Pituitary gland?

  • Reply Burnett Fitness February 27, 2017 at 12:09 am

    Great video. Very helpful

  • Reply AHMED Ali April 18, 2017 at 12:16 pm

    Thank you very much I strongly appreciated what U think of us 🌹I v got lots knowledge never know before

  • Reply Gaurav Murali April 19, 2017 at 6:20 am

    useful…thumbs up!!

  • Reply BritneyFreak34812 June 5, 2017 at 12:19 am

    You sound like Norman Bates from Bate's Motel 😂

  • Reply sunny kem July 15, 2017 at 2:43 am

    you forgot about the THYMUS GLAND and PINEAL GLAND..?

  • Reply 0311campbelljk September 15, 2017 at 4:30 am

    This guy takes the Endocrine system to a whole new level

  • Reply Hana SJ October 12, 2017 at 4:30 pm

    Thank you so much Mr! 😊😊

  • Reply Parav Kumar November 10, 2017 at 4:05 am

    What about pineal body and thymus sir

  • Reply Neha Parveen November 12, 2017 at 2:54 pm

    How endocrine gland pour there secretion directly in blood…..bcz blood is present in a capallaries n arteries so there secretion enter directly in blood?

  • Reply Nafis Laskar November 13, 2017 at 1:16 pm

    I am thinking that what does men have in the place of the ovary? Is it blank there or not??

  • Reply PaulIvanish November 27, 2017 at 10:24 pm

    Glucagon. With an 'o'.

  • Reply random *idk what to put in this* January 22, 2018 at 2:08 pm

    BlameitonJorge, is that you?

  • Reply M J February 20, 2018 at 5:40 pm

    Hypothalamus is not a gland😱

  • Reply GoldenLuckyCharms April 4, 2018 at 11:01 pm

    This was really helpful, I tried a crash course video but he just goes too quickly through it all and it's hard to embed

  • Reply paul fears April 17, 2018 at 5:30 am

    why does that guy have a giant overy

  • Reply tracy scanlon May 16, 2018 at 9:22 pm

    Woman don't have an adams apple

  • Reply Benita Jones July 4, 2018 at 9:32 pm

    Hippos put those parakeets against great pancakes
    Hypothalamus, pituitary, thyroid, parathyroid, Adrenal glands, gonads, pancreas

  • Reply Taim26 July 8, 2018 at 2:36 pm

    سبحان الله

  • Reply D. V. August 18, 2018 at 11:10 am

    "If you hold your hand right around your Adam's apple…"
    Dude, seriously?!

  • Reply vinitha sekaran August 25, 2018 at 7:24 pm


  • Reply Isidora S October 21, 2018 at 8:24 pm

    Very useful!! thanks

  • Reply Daddy Thomas October 27, 2018 at 2:05 pm

    Don’t forget for the TEAS, the hypothalamus secretes dopamine, which regulates mood and behavior.

  • Reply ? November 4, 2018 at 8:18 pm

    This is a big help thanks

  • Reply STANJUNE STANJUNE February 2, 2019 at 9:11 pm

    Great video Man!

  • Reply caitlin oliver February 12, 2019 at 11:43 am

    Need to make video for teas pre exam

  • Reply James Goude February 14, 2019 at 1:34 pm

    I thought that the neurohypophysis secretes oxytocin & ADH

  • Reply Taylor Evans March 19, 2019 at 1:09 am

    has anyone studied from this for the TEAs test ?

  • Reply Sean Bradford April 11, 2019 at 6:20 pm

    Glucagan: It's an like Danky Kang.

  • Reply habibty habibty May 9, 2019 at 11:33 pm

    Thank you, you are life saver

  • Reply Just Jules June 5, 2019 at 4:09 am

    This helped with my Study thanxs 🙂

  • Reply Rain pop instagram MsCheddargetter June 8, 2019 at 12:55 pm


  • Reply Noobdestroyer 47 June 28, 2019 at 9:16 am

    It’s a me

  • Reply achteachte yo July 8, 2019 at 10:34 am

    Why is this guys pronunciations so weird?

  • Reply Treasure July 17, 2019 at 9:56 pm

    he sounds like gabe from the officec

  • Reply Arryanna 101 September 7, 2019 at 4:32 pm

    the pineal gland: releases melatonin for your circadian rhythm (internal clock).

  • Reply Divyam kashyap September 14, 2019 at 3:06 pm

    very bad English kuch to clear hi nhi ho rha h

  • Reply bethany Reiss September 16, 2019 at 6:35 pm

    This was soooo helpful, thanks for making my test 100 times easier to understand!

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