 You're walking in the woods and suddenly a bear comes out of nowhere and startles you What happens next? That's what we're gonna explore in this video. And when you're getting started, you know what's happening inside your body? Well, your brain immediately activates your adrenal glands via the nervous system. Adrenal glands are this tiny hat-shaped glands that are sitting on your kidneys. Since you have two kidneys, you have two adrenal glands. And if you look inside the adrenal gland, you'll actually see that there are two parts to it. You have the middle part, which is called the medulla. This is called the medulla. And I remember it as it's the middle part, middle medulla. And then you have this outer part, which is called the cortex. I remember this as covering, external covering, cortex, covering external. So that's how I remember these names. And your nervous system activates the middle section, the medulla. And in this video, we're going to focus only on what happens when the medulla gets activated. Well, the moment the medulla gets activated, well, this is a gland. Therefore, it's going to release hormones. That's what glands do. Now, the medulla releases two hormones. You are probably very familiar with one of them at least. I'm guessing it's called the adrenaline. And there is another hormone, which I like to think of it as a sister hormone, because its chemical composition is very close to that of adrenaline. It is so close. It looks so similar to it that we also call it pretty much like adrenaline, but we can't call it the same name. So we call it noradrenaline. And you know what these hormones do? Their job is to prepare your body for this fight or flight situation. Therefore, it's also called the emergency hormone. Its main job is to get you out of this immediate danger as quickly as possible. But how does it do that? Well, like any hormone, it will be going into the bloodstream. So this medulla starts releasing these hormones. They go into the bloodstream. And then once they enter into the bloodstream, since the blood is circulated throughout the entire body, you will find that these hormones are now everywhere in your body. And whichever organs, whichever cells has receptors to these hormones, all the hormones will bind to it and it will start affecting them. But what effect do these hormones have on your body? Well, let's try to figure this out logically. Remember, our goal is to try and either run away from this bear or to fight it. What would you need to do or what would you need, what your body need to get in order to do that? Well, the most important thing for your body is to get power. Power means ability to spend more energy per second. And that's basically what these hormones are going to help you do that. But how exactly? Well, we get energy by using oxygen to break down glucose. So if you want more energy, we want more oxygen. How do you get more oxygen? Well, you make yourself breathe faster. And therefore this is one of the effects of your adrenaline and non-adrenaline. They bind to the appropriate respiratory organs and they're going to help you breathe faster. Okay, what else is going to happen? Well, it's not enough just to get more oxygen in your body. You also need to supply more oxygen more quickly. That means the blood in your body needs to flow faster. The blood in your body needs to be at higher pressure so the oxygen can diffuse out and diffuse into the cells. So how do you do that? Well, to make your heart, you do that by making your heart work faster. So they also bind to your heart cells and it makes it beat faster. Okay, now your cells are getting a lot of oxygen. What else? Well, remember, you want more energy. So you also want more glucose because you want the oxygen to break down glucose. How do you get more glucose now? Well, think about it. Where do you get more glucose from? Hey, you get glucose from all the glucose reserves or glycogen that's there in your kidney. Sorry, not kidney, in your liver. So it also stimulates the liver, these hormones also stimulate the liver and make it give more glucose. It actually makes it break down glycogen faster into glucose and makes it glucose available for you. And so with all these three, now your cells start getting more oxygen, more glucose and they can now start working faster and provide more energy to you. But that's not it. Our body is way more efficient than this. You don't need all the parts of your body to start working harder, right? For example, why would you need your digestive system to work harder? You don't need that. Why would you need your reproductive system at this point in time to work harder? You don't need that. So our body is also very smart. So you know what this hormones do? They also ensure that they redirect the blood to the right cells. So they make sure that a lot of blood starts flowing to the skeletal muscles. The muscles that you need in your hands, in your legs, if you want to run or if you want to fight. So they also redirect the blood. Of course, the other cells are also getting the blood, but it'll make sure that more blood reaches over here. And they do that by constricting certain blood vessels and by dilating the other ones. And these hormones also make you a little bit more alert. For example, by dilating your pupils. In short, these hormones get your body into super mode. And now your body is prepared to either fight the bear or get out of there.