Hello, hello, my dear anatomy students! How are they? Welcome to a new anatomical video on this channel, Easy Anatomy, by Juan José Sánchez.
Today I bring you the video of the generalities of the endocrine system, this wonderful system that is very unknown to most, but that plays a very important role in our body. Since this endocrine system produces a series of substances that are essential for life, essential for development. Ok, then, well, come with me then to see this wonderful system.
What is the endocrine system? Surely you may have heard it, but you don't know what it is, what it does. Well, the endocrine system, like any system or device, but I haven't read it as much as the endocrine system.
Although it would be good from a semantic point of view, let's say that it is the set of organs, every apparatus system is a set of organs, as I have told you in the previous videos, that this set of organs are called glands and that these glands produce a series of substances that are released directly into the bloodstream. These substances that are released by the endocrine glands, in this case, are called hormones. Then, the set of organs that is responsible for releasing substances that go directly into the blood are called: the organs of the endocrine system as such.
And you will say, why do they release substances into the blood, for what purpose? Well, I explain to you, these substances that are released into the blood are called hormones. A hormone is nothing more than a chemical messenger, it is the way in which the different organs of the human body can communicate with each other through substances.
Why is it released into the blood system? because through blood, like blood in the circulatory process, it will go around the entire organism. If I send a substance directly into the blood, I can probably communicate with the entire body through that substance.
So, see how wonderful this communication system is that the endocrine system and many organs of our body have that function only if another tells them what to do, when to do it and how to do it. So, the endocrine system is this, it is the stimulation that an organ can give to some cell or to some other organ that is very far away from it to tell it to do an action or even to stop doing an action. That is very important.
Now, for what purpose do we study the endocrine system or why does the human body have an endocrine system? Well, from what I am explaining to you, imagine that I am the growth hormone that is secreted by a gland called the pituitary gland. I give you an example at the level of the brain and this growth hormone has to stimulate the growth of all the other structures of the body.
So, the way the body has to be able to tell all the cells, all the bones, all the muscles, all the organs, that you have to grow, is through this substance called growth hormone. So, see that they are messengers, we absolutely depend on the endocrine system for our proper functioning. Now, glands in general, when we look for the concept of gland, it is said that a gland is any organ that is responsible for creating and secreting a substance.
Now, according to this, we can divide glands into endocrine glands and exocrine glands. What is an endocrine gland? Good!
An endocrine gland is that gland, see, that the cellulite that forms more or less so that, so you can see, the endocrine glands are those glands whose secretion product goes directly into the blood and is called a hormone, the product directly into the blood. When an organ secretes a substance and this substance goes into the blood, it is considered an endocrine organ. Okay, now exocrine glands are those glands that also have secretion products, see the example here.
This is an example of a sweat-producing gland, for example, sweat, but the secretion product of this gland does not go into the blood but goes through a duct. Generally through a duct to the outside, such as the pancreatic juices of the pancreas, such as the bile ducts, such as the ducts of the salivary glands, such as the ducts of the sweat glands. Ok, they are substances that do not go into the blood but rather go outside or into some body cavity.
That is the difference between endocrine and exocrine gland. The only ones that are part of the endocrine system are the endocrine ones, of course, the exocrine ones are not part of the endocrine system. Let's see then, what are the organs and more or less their function, those that make up the endocrine system?
But first, no, don't take off from the video. [Music] It is vitally important that you subscribe to the channel! Down here, where you see that it says subscribe, you click on it and you are subscribed to the more than 325 anatomical videos that are there.
If there is one that you don't find on the channel, write it to me in the comments. Don't forget to tell me from which country you are watching me, from which university, so I can have an overview of where my audience comes from. So, well, we had been talking about the organs of the endocrine system, more or less what the system consists of.
So we are going to go from top to bottom, from the most cephalic to the most caudal. Let's start first with the central, literally the central of the endocrine system, which is the hypothalamus. The hypothalamus is an organ found within the brain, which is the one that commands the entire endocrine system, or rather most of it.
There are certain glands that escape the control of the hypothalamus, but the hypothalamus is in charge. It is a small structure that is located at the level of the diencephalon and that, apart from having nervous functions, has the function of creating hormones. OK?
That stimulate the gland that is just below it, which is the pituitary gland. Ok, there is another set of hormones that are from the hypothalamus that do not stimulate the pituitary gland, but can directly stimulate other body organs, but in itself, the hypothalamus is in charge. It is like a military hierarchy, the endocrine system, as if this were the general and he commands the captain who has less command than him, that the captain would be the gland that is just below, which is the pituitary gland.
How do you send it? Because it releases hormones that, since they are very close to each other, are communicated by a blood plexus, a blood vessel, I mean. These hormones, leaving the hypothalamus, directly stimulate the pituitary gland below.
Ok, and the pituitary gland, also called the pituitary, is second in command, so to speak. It is also located at the level of the brain, it receives orders from the hypothalamus so that it can release another hormone in turn, which is the hormone that will stimulate the rest of the glands in the body. So, the hypothalamus, for example, if it wants to tell the thyroid gland to secrete thyroid, the hypothalamus cannot tell the thyroid gland directly.
The hypothalamus has to tell him, since he is the general, he has to tell the captain, who is the pituitary gland, and the pituitary gland, please tell the thyroid gland that I need you to secrete thyroid hormone. Then, the pituitary gland listens to it and releases a hormone that finally tells the thyroid gland to release thyroid hormones. And thanks to the stimulation of the pituitary gland, for example, the thyroid gland begins to produce hormones.
So, see that it is always a command mechanism, that is, one gland commands the other. So, the two that are most in charge, let's say those of the military high command, are those in the brain, which are the hypothalamus and the pituitary gland. So, since we have the glands under the neck, we are going to have the thyroid gland first.
This thyroid gland, a single central gland, as well as the hypothalamus and the pituitary gland, which is located in the anterior part of the neck, embracing the trachea, is responsible for producing thyroid hormones, which are T3 and T4, mainly . These two also produce other hormones, but those are the two most important ones, which are responsible for accelerating the metabolism in general, which are hormones that are responsible for increasing the metabolic rate in a general way. It is controlled by the pituitary gland and in turn the pituitary gland by the hypothalamus.
There are glands that are behind the thyroid, which are the parathyroid glands, small, they look like lymph nodes. This gland is parathyroid or parathyroid, they release a hormone called PTH, pth is the abbreviation of parathyroid hormone or parathyroid hormone, this parathyroid hormone is the one that has an important role in the metabolism of calcium and phosphorus at the level of bones and its excretion at the renal level. Now, these parathyroid glands have a peculiarity in that they are not governed by the hypothalamic-pituitary axis, but rather the parathyroid governs itself.
They regulate calcium and phosphate levels in the blood. OK, it is not controlled by the hypothalamus and the pituitary gland. They escape your control.
The next important gland is already found at the level of the abdomen, which is the pancreas in the retroperitoneum. This pancreas has a very important function from a digestive point of view because it secretes pancreatic juices, but from an endocrine point of view it produces two main hormones. There are several, I repeat, but there are two that matter to us: one is insulin and the other is glucagon.
Insulin is a hormone that has to do with lowering blood glucose or blood sugar levels , however you want to say it. While glucagon does the opposite, glucagon is responsible for increasing blood sugar levels. So, it has to do with carbohydrate metabolism.
This pancreas is the organ that is, for example, affected in cases of diabetes mellitus. Well, then we have the adrenal glands, which are a pair of glands that are on top of the kidney, but have nothing to do with the kidney. They are simply located there, they gave it that name because it is there, but they are not part of the kidney.
This adrenal gland produces quite important hormones. First, in its most central portion, which is the spinal cord, they produce the famous catecholamines, which are adrenaline and norepinephrine. Remember that these are hormones that have functions from a general point of view: they increase the heart rate, increase the respiratory rate, increase the force of cardiac contraction, the famous adrenaline.
And they also produce other hormones such as aldosterone and cortisol. Aldosterone has to do with the regulation of body fluids and cortisol is a steroid that we have endogenously, it has many, let's say, bodily functions. Then, we have the testicles.
Something I forgot to tell you is that the adrenal glands are controlled by the hypothalamus and the pituitary gland, but not the pancreas. Only the pancreas and the parathyroid are the only two large glands that are not governed by the hypothalamus and the pituitary gland. Only the pancreas and parathyroid are not governed by the hypothalamus or pituitary gland.
The testicles, for their part, are controlled by the hypothalamus, the pituitary gland. They are unique to males, they are housed in the scrotal testicles and are responsible for secreting a hormone called testosterone, which is a hormone that has to do with the appearance of secondary sexual characteristics in men. While the woman, instead of a testicle, has a pair of ovaries that are in the abdomen.
These are responsible for secreting two main hormones. One is estrogen, which stimulates the formation of secondary sexual characteristics in women, and also produces progesterone, which has several functions in the body. One of them is to maintain the pregnancy.
So, very good. This would be a general outline, let's say, anatomical-physiological of the endocrine system.
