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  • Hi. It's Mr. Andersen and welcome to the Endocrine System podcast. If you look

  • way up there at that guy, his name is Robert Wadlow and that guy, I have not idea what

  • his name is because he's not Robert Wadlow. Robert Wadlow is the tallest man that we have

  • in modern day. He was something like 8 feet 11.5 inches at the time of his death and he

  • was that tall because he was a pituitary giant. In other words, he had a tumor, we now know,

  • that was pushing on his pituitary. It was making it produce a hormone called growth

  • hormone which made him get as tall as he eventually was. And so that wasn't normal. It does put

  • pressure, and he died young just mostly I think due to circulation problems. He started

  • to get blood clots. And so basically it talks a little bit about the endocrine system. When

  • I'm talking about the endocrine system, the other system that's really important to talk

  • about is called the nervous system. So the nervous system remember is basically going

  • to be made up of neurons. So you have all these dendrites that come into the cell bodies.

  • So the cell body looks like this and then you have an axon that comes way down here

  • and then you're going to have another neuron down here that's connected with a bunch of

  • dendrites to a cell body and it's going to move here. Now this distance right here, or

  • excuse me, the separation between the two is called a synapsis. A synapsis is going

  • to be a gap between neuron 1 and neuron 2. Now why is the synapse important? Well, we

  • get control over the chemicals that we send. But this podcast isn't about the nervous system

  • and the reason why is that nerves just travel in one direction, from this neuron to another

  • neuron onto another neuron. They just go in one direction. And so my analogy is it's like

  • Gmail. When you send an email from one person to another person or they send it from one

  • person to another person, that's like the nervous system. You're sending a message from

  • one person with a clear destination and that's the nervous system. It goes really fast and

  • it's going to target a specific cell. And so when do we use the nervous system? When

  • he have to do something really quick. So if somebody were to throw something at me and

  • I were to dodge it, that would be my nervous system that is acting. So the endocrine system

  • is more like Facebook. If I were to post to my Facebook status update that I am working

  • on a cell communication podcast by myself. Ironic. And I just put it out there, there's

  • going to be a delay. There's going to be time before other people look at it and dislike

  • it or like it or respond to it. And so that's going to be more like the endocrine system.

  • I'm sending it out to everybody and whoever wants to respond to it can. And so basically

  • keep that in the back of your mind. What are some terms that you should understand? First

  • of all anything that is going to send out these messages in the endocrine system is

  • called a gland. And we'll go over ten important glands. The chemical that they send out is

  • called a hormone. And then it's going to target cells or not. It may target certain cells

  • or it may not target other cells. And so we could send for example follicular stimulating

  • hormone from the pituitary. It's only going to effect the ovaries and the testes, but

  • if we send out growth hormone that's going to effect all the cells in your body. So what

  • do those hormones do? They simply diffuse throughout your body. They're going to spread

  • throughout your body. And so they are going to bump into cells or not. They're going to

  • spread throughout your whole body and that's why if you've ever felt like adrenaline, you

  • almost get in a car accident, you just feel like almost something coursing through your

  • body, that's going to be your endocrine system. Now when they find cells one of two things

  • can happen. If they are a water soluble hormone, an example could be epinephrine or adrenaline,

  • they're water soluble, basically what they're going to do is they're going to dock with

  • a protein on the surface of their cell. Since they're water soluble they can't gain entry

  • to the cell. And so usually what they'll do is they'll set up some kind of signal transduction

  • pathway to have some kind of an action out here or have another action inside the nucleus

  • where we could make certain specific genes or certain proteins, transcribe certain genes.

  • But that would be water soluble. We also have what are called lipid soluble. Testosterone's

  • an example of that. Basically since it's lipid soluble it's going to move right through that

  • lipid by layer that is the cell membrane and it also can target with the cell and move

  • right into the nucleus, because again there's going to be a lipid by layer here as well.

  • And so lipid soluble hormones are going to move all the way into the cell. Water soluble

  • are just going to dock with the receptor protein on the surface. And so here's our endocrine

  • system. The endocrine system is not as tightly linked together like the circulatory system,

  • but again it doesn't have to be because it's sending hormones through out the whole body.

  • And so basically we've got glands going all the way up to the top from the pineal gland

  • all the way down to the ovaries and testes on the bottom. And so basically what I want

  • to do is I've chose ten glands in the endocrine system, ten that I think are pretty important.

  • There are more than that. And then I've just chosen one hormone for each of these and we're

  • going to talk about that. So let's talk, let's start at the top. The first one is going to

  • be the pineal gland. The pineal gland is right here. Basically what the pineal gland is going

  • to secrete is a chemical called melatonin. It does that only when it's night time. And

  • so if your eyes are open during the day you're not going to be secreting melatonin. But when

  • you close your eyes at night, it's going to start giving off melatonin. And so basically

  • what that does is that it allows our brain to tell what time of the day it is and it

  • also allows us to figure out what season it is. And so basically we can set up what's

  • called our circadian rhythm. So it's basically our internal clock and it's pineal gland doing

  • that. Next let's move down here. This part of our brain is actually called the hypothalamus.

  • And the hypothalamus is kind of the connection between the brain and the endocrine system.

  • And so it can secrete hormones as well, but we're going to say it's influencing the pituitary.

  • We're going to talk about what the pituitary does. Pituitary basically, if we were to look

  • at it like this, the pituitary let me blow that up a little bit, so the pituitary is

  • going to go down like this and so it's going to have two lobes to it. It's going to have

  • the anterior, anterior means towards the front or towards the head, and then it's going to

  • have the posterior. Posterior is going to be towards your rear end is the best way to

  • think about it. And so what is the anterior pituitary give off? Well it gives off growth

  • hormone. It gives off a number of other things, it gives off endorphins, it gives off follicular

  • stimulating, it gives off all these different hormones, but one that we're going to talk

  • about is growth hormone. What's growth hormone going to do? Growth hormone again is going

  • to float throughout the rest of your body. It can do that in the circulatory system or

  • through the interstitial fluid and basically it's going to cause the cells to grow. So

  • they're going to get bigger. If we talk about the next one, anterior, or excuse me, posterior

  • pituitary, it gives off oxytocin but the one important hormone we are going to talk about

  • is anti-diuretic hormone or ADH. And so anti-diuretic hormone, well you know what "diure" is, so

  • what is anti-diuretic? Anti-diuretic is going to be a hormone that holds on to fluids inside

  • our body. Where is that going to go? It's going to go to our kidney because our kidney

  • is in control of osmoregulation. What's the next one. The next one as we work our way

  • down is going to be the thyroid. So we're going to move all the way down here this would

  • be the thyroid gland. It sits right in here. Basically it does two things that are important.

  • It gives off what are called T3 and T4. Those hormones and the numbers relate to the number

  • of iodine atoms that are found within it. And so basically maybe you've heard of a goiter,

  • when you get an inflamed thyroid. Basically what our thyroid does is it regulates metabolism.

  • And so it's going to give off these two chemicals T3 and T4 and that's going to speed up metabolism

  • inside our body. And so if you have a hyperactive thyroid you have high metabolism. If you have

  • an inactive thyroid then you're going to have really slow metabolism. And so basically it's

  • control of that. And the other thing that it does is it secretes something called calcitonin.

  • And again endocrine system's really important in feedback loops. And so the calcium that

  • we have in our blood, the level that we have is super important. Especially in nerves and

  • in muscle firing. If we don't have the correct amount of blood calcium, we're going to die.

  • And so basically what the thyroid does, is that when you secrete the thyroid, it's going

  • to lower the calcium. Where's the calcium going to go? It's going to go back into the,

  • we're going to secrete some through the kidneys, but it's going to go back into the bones.

  • And so there's another hormone that kind of goes with that and so this looks like a butterfly,

  • but there are going to be these tiny little hormones in here called the parathyroid. They

  • sit right within the thyroid. And their going to secrete something called parathyroid hormone.

  • What does that do? Well, if the blood calcium level goes too low, it's going to raise the

  • blood calcium. And so these two, the thyroid and the parathyroid are going to work together

  • to basically keep the blood calcium level correct. It's the same way that insulin and

  • glucagon work in the pancreas. Speaking of which, let's go to the next one. And so the

  • pancreas is kind of hard to see in this diagram. But the pancreas is going to sit right here,

  • it's again behind the stomach and it's going to empty right here into the duodenum. So

  • it's going to empty enzymes in here, but it's also on its surface it's got beta and alpha

  • cells that are going to secrete insulin and glucagon. Insulin is going to be secreted

  • if we ever need to lower the blood sugar and glucagon if we ever need to raise the blood

  • sugar. So basically what insulin does is when it's secreted it allows our cells to take

  • in that blood sugar, that glucose. And glucagon, when we release that it's going to release

  • more of that glucose from the glycogen that's found right here in the liver. So that's the

  • pancreas. On the top of our kidneys, so these would be our kidneys right here, on the top

  • of them we have our adrenal glands. The adrenal glands have two parts to it. The adrenal cortex

  • is going to be on the outside. The adrenal cortex is basically what it does is secretes

  • glucocorticoids. And so if you ever have an injury and you get huge amounts of inflammation

  • in it, they secrete anti-inflammatories. And so if you've ever taken an anti-inflammatory,

  • an example would be like Advil, basically the glucocorticoids are going to do the same

  • thing. They don't need to act right away, and so these are actually connected by hormones

  • to the pituitary so the message can come from the brain, we have an injury down to the pituitary

  • and eventually to the adrenal cortex. But that's not what you're familiar with in the

  • adrenal gland. You're familiar with adrenaline. So there's a nervous connection from the brain,

  • all the way down here to the center of the adrenal gland. That's called the adrenal medulla.

  • Basically what it's going to have it do, it's going to secrete epinephrine. Epinephrine

  • is adrenaline. It's going to go throughout your body and it's going to trigger that fight

  • or flight response. And so again, if you almost get into a car accident, nervous system is

  • going to allow you to kind of not get in that car accident, but after that you're going

  • to feel this adrenaline coursing through your body. Your metabolism is going to speed up.

  • You're to suppress like your digestive system. You're going to become more alert. And that's

  • all a result of the adrenal medulla. Next we've got, down at the bottom, we just have

  • the sex hormones and the sex glands. We've go the ovaries, and so this would be in females,

  • and then the testes if we're talking about males. Ovaries are going to give off estrogen.

  • Testes are going to give off testosterone among other things. But basically those are

  • responsible for your female and male sex characteristics. Now when you go through puberty, before you

  • go through puberty they're not really cranking out a lot of estrogen and testosterone. But

  • once you go through puberty, they're getting a signal from the pituitary gland that says

  • now it's time to make these sex hormones and then we get those secondary sex characteristics.

  • Okay, so how did you do? Can you remember the ten glands? Can you remember the hormones

  • that they secreted? And what they did? Well, let's try. Okay. So as we go through this

  • . . . Testes - Where are they found? They're found right down here. What do they do? They

  • give off . . . testosterone, that's right. What about the ovaries? Where are they found?

  • Ovaries are going to be found right here. What do they give off . . . estrogen, that's

  • right. Sorry for the awkward pauses. It's like Dora the Explorer. Next we've got the

  • adrenal medulla. Where's that found? Yeah, that's the green. What do they give off . . . that's

  • right, epinephrine. Let's got to the next one, adrenal cortex. Where is that? It's going

  • to be the yellow part remember around the adrenal gland. What do they give off? I bet

  • you've forgotten this, those are glucocorticoids. They're going to be anti-inflammatories. What's

  • next? That's going to be the pancreas. Pancreas is found right here. What's it give off . . . insulin,

  • glucagon. Those regulate blood sugar. Let's go to the next one. It's the parathyroid.

  • That's right, that's going to be within the thyroid. They used to actually when people

  • get goiters, they cut parts of the thyroid out and then person would immediately die

  • because they didn't understand what the parathyroid did. So a parathyroid is going to be inside

  • here. What's it going to secrete . . . parathyroid hormone, that's right. And that's going to

  • raise blood calcium. Right above that we've got the thyroid. Thyroid is going to give

  • off two things. Can you remember those . . . It's going to give off calcitonin, that's going

  • to lower blood calcium and it's also going to give off T3 and T4. Okay. Let's go to the

  • next one. Posterior pituitary. So that's going to be way up here. What does that give off

  • . . . anti-diuretic hormone. That's right. That's going to keep our body holding on to

  • water, retaining water. And then we've got the anterior pituitary in the front. That

  • gives off a lot of things. Do you remember what it gives off . . . thinking back to Robert

  • Wadlow . . . right, it gives off growth hormone. That's going to cause our cells to grow. And

  • finally we've got the pineal gland. Pineal gland, close your eyes, you're going to start

  • secreting . . . melatonin, that's right. And that allows us to sync up our circadian rhythms.

  • So these are the top 10 glands, top 10 hormones and I hope that's all helpful.

Hi. It's Mr. Andersen and welcome to the Endocrine System podcast. If you look

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B2 US hormone pituitary thyroid endocrine endocrine system adrenal

The Endocrine System

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    Wayne Lin posted on 2015/06/28
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